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Enabling Applications for Grid Computing with Globus

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1. Figure 2 5 Grid portal on an application server Application enablement considerations Portal Whatever the user interface might be to your grid application ease of use and the requirements of the user must be taken into account As with any user interface there are trade offs between ease of use and the ability for advanced users to provide additional input to the application or to specify run time parameters unique for a specific invocation of the job By utilizing the GRAM facilities in the Globus Toolkit it is also possible to obtain job status and to allow for job management such as cancelling a job in progress When designing the portal the users requirements in these areas must be understood and addressed Developing a portal for grid applications is described in more detail in Chapter 8 Developing a portal on page 215 2 2 Non functional requirements The following sections describe some additional considerations related to the infrastructure These considerations come under the heading of non functional as they do not relate to a specific functional unit of the grid such as job management broker and so on Chapter 2 Grid infrastructure considerations 35 2 2 1 Performance When considering enabling an application to execute in a grid environment the performance of the grid and the performance requirements of the application must be considered The service requester is interested in a quality of
2. see javax servlet http HttpServlet void javax servlet http HttpServletRequest javax servlet http HttpServletResponse public void doPost HttpServletRequest req HttpServletResponse resp throws ServletException IOException performTask req resp public void performTask HttpServletRequest request HttpServletResponse response throws ServletException req request res response res setContentType text html res setHeader Pragma no cache res setHeader Cache control no cache try out res getWriter catch IOException e System err print In Application getWriter e Read and validate user input initialize 226 Enabling Applications for Grid Computing with Globus try Which button selected submit req getParameterValues submit getresult req getParameterValues result getstatus req getParameterValues status logout req getParameterValues logout Which application was selected appselect req getParameterValues appselect if submit null amp amp submit length gt 0 submitApplication submit Application else if getresult null amp amp getresult length gt 0 getResult get run result else if getstatus null amp amp getstatus length gt 0 getStatus get Application status else if logout null amp amp logout length gt 0 doLogout logout else invalidInput
3. h And Wait for i 0 i 8 i if Current CanPlay i job i gt Wait worse case 1 100000 Here we are reading the eval files All the jobs has been completed so we should have all the results Appendix B C C source code forexamples 335 in the eval file ifstream results eval while results eof results gt gt k gt gt s get the best one if s gt 1 1 s store its value toplay k remember the column to play h 5 results close nothing in the file that means we cannot play so it is NULL if 1 100000 cout lt lt NULL lt lt endl break E AI plays here and checks if it won Current Play toplay WHITE if Current HasWon toplay WHITE Current Display break E h finished stop everything StopGASSServer SmallBlueSlave C include lt iostream gt using namespace std include GAME C main int arc char argv GAME Current XSIZE YSIZE Current FromDisk which column should we simulate int col atoi argv 1 int start Current Value col WHITE Current Play col WHITE int 1 0 s k for k 1 k XSIZE 1 k s Current Value k BLACK 336 Enabling Applications for Grid Computing with Globus h if s gt 1 15s start 1 send back the information to the server cout col start endl GAME Class include string include lt iostream gt include lt fstream gt
4. we submit jobs in the background get their process id and uses the wait command to wait for their completion 350 Enabling Applications for Grid Computing with Globus this method is also used for the jobs submission echo Transferring executable files for i in 1oop do gsissh p 24 Nodes i d TMP mkdir TMP amp ProcessID i done for i in 1oop do wait ProcessID i gsiscp P 24 GenerateDraws Nodes i TMP amp ProcessID i done for i in 1oop do wait ProcessID i gsissh p 24 Nodes i chmod x TMP GenerateDraws amp ProcessID i done file should be made executable fon all the execution nodes echo Jobs submission to the grid for i in 1oop do wait ProcessID i echo Nodes i EXE cd TMP GenerateDraws n grep param amp amp echo GOT IT on HOSTNAME gsissh p 24 Nodes i EXE amp ProcessID i done for monitoring we copy locally the Monitor files created on each compute nodes This file content the percentage of tested draws Each files is suffixes by the nodes number statusnum is actually the sum of all the percentage Monitor files devided by 100 When it equals the number of nodes that means that we have finished echo Monitoring statussum 0 while statussum NodesNumber do echo sleep 5 we poll every 5 seconds statussum 0 for i in 1oop do gsiscp q P 24 Nodes i TMP Monitor Monitor i
5. amp resourceManagerContact host1 executable amp resourceManagerContact host2 executable amp resourceManagerContact host3 executable _ globusrun is a blocking shell command that will wait for the completion of the jobs Consequently we run globusrun in the background so that the submission script SubmitGlobus in this example can continue running and acts as a non blocking command The wait command can be used to wait for the completion of this command However in the example it is not really required Example 9 3 Building a multi request query for globusrun echo Jobs submission to the grid rsl for i in 1oop Chapter 9 Application examples 255 256 do echo Nodes i rs1 rs1 amp resourceManagerContact Nodes i rsl rs1 executable GLOBUSRUN_GASS_URL PWD GenerateDrawsGl obus sh arguments TMP n param subjobStartType loose barrier file stage _in GLOBUSRUN_GASS_URL PWD GenerateDrawsG lobus GenerateDrawsGlobus TMP file_clean_up GenerateDrawsGlobus TMP environment LD LIBRARY PATH GLOBUS_LOCATION 1ib done echo rs1 start the commands in the background to be non blocking globusrun s o rs1 amp Note subjobStartType loose barrier must be used in the RSL commands to avoid premature ending of the sub jobs that do not terminate at the same time as the others because they run slower Job submi
6. body out printIn htm1 238 Enabling Applications for Grid Computing with Globus private void submitGene String title Submit gene application out printIn html out printIn head out printIn title title lt title gt out printIn lt head gt out println body bgcolor cfd09d text 000099 gt out println hl align center gt title lt h1 gt out printIn body out printIn html1 private void submitTest String title Submit test application out printIn html out printIn head out printIn title title lt title gt out printIn head out println body bgcolor cfd09d text 000099 gt out printIn lt hl align center gt title lt h1 gt sendResult doProxy jspBean addJobId doSubmit mdsHost testApp out printIn body out printIn html1 private void submitDemo String title Submit Demo application out printIn html out printIn head out printIn title title lt title gt out printIn lt head gt out println body bgcolor cfd09d text 000099 gt out println hl align center gt title lt h1 gt out printIn body out printIn html1 private void getStatus String myJobIds String t
7. e eee eee 73 4 1 2 Shared data access eee 74 4 1 3 LOCKING ocu EER 75 4 1 4 Temporary data spaces selle 76 4 1 5 Sizeofdata nee 76 Enabling Applications for Grid Computing with Globus 4 1 6 Network bandwidth LL 77 4 1 7 Time sensitive data llle 77 4 18 Data topology ii 4e noe EXTR ole LR mone whe e DSa 77 41 9 Data tyD6S 15 ere oth RE acta da pde GE cand anes ene 79 4 1 10 Data volume and grid scalability 020002000 80 4 111 Enetypted data oae EE CER RR curn Be 84 4 2 Data management techniques and solutions 85 4 2 1 Shared file system 85 4 2 2 Databases er ee 86 4 2 3 Replication distribution of files across a set of nodes 86 4 2 4 Mirroring ues i e tie ae WOES ser EU Dn RR eaves ROI RIS 87 4 25 CACHING as vientos DRE Ih dana Lea TETTE PUR Bu D 87 4 26 Transfer agent censere PR PRSE e ee Ee ud 88 4 2 7 Access Control System 88 4 2 8 Peer to peer data transfer 88 4 2 9 SANADOXIAG oni dr Bee dah edie s Ga hee dale 89 4 2 10 Data brokerlng eorr cR eem el ate a 90 4 2 11 Global file system approach 90 42 12 SAN approach io aevum ARE et ER efe PUR etg oae 93 4 2 13 Distributed approach 95 4 2 14 Database solutions for grids LL 98 4 2 15 Data brokering leise 100 4 3 Some data grid projects in the Globus community 102 4 3 1 EU DataGrid osc hae ede ee Re EAR RE x 102 4 3
8. gt globus url copy will be used to copy the Monitor file from the execution nodes to the submission nodes gt globus gass server will start a GASS server on the execution nodes that will be used to copy the Monitor file generated by GenerateDrawsGlobus and used to monitor the status of the job All the programs used in the previous example are slightly modified but are still used for the same purpose The modified versions for this example are renamed with the suffix Globus for example SubmitGlobus is the submission script and GenerateDrawsGlobus is the program generating random numbers See GenerateDrawsGlobus C on page 352 and SubmitGlobus script on page 353 The sample broker developed in ITSO broker on page 327 will be used as in the previous example to obtain execution host names 254 Enabling Applications for Grid Computing with Globus node 1 draw Monitor globusrun pu gassserver Sa rode 2 Submit 1 2 20 31 12 za Monia onitor 1 7 Monitor 2 777 NC uml Monitor n e 77 C gasssever gt Figure 9 2 Lottery example using Globus commands node n SI Monitor Submitting the jobs The tag ressourceManagerContact will be used for the RSL string to specify a multi request query Each resourceManagerContact indicates one execution node The structure of the query is
9. job getStatusAsString if job getStatus GramJob STATUS DONE synchronized this notify Again we enhance the RSL string so that the output will be rerouted to our client and finally we run the application Example 6 36 Interactive GASS example 3 of 3 private synchronized void runJob Chapter 6 Programming examples for Globus using Java 159 RSL String to be executed String RSL amp executable bin 1s directory bin arguments 1 String gRSL null Resource Manager Contact String rmc t2 itso tupi com gRSL a RSL substring 0 RSL index0f amp rsl substitution GLOBUSRUN GASS URL gURL RSL substring RSL index0f amp 1 RSL length stdout GLOBUSRUN_GASS_URL dev stdout JobID stderr GLOBUSRUN GASS URL dev stderr JobID PUn Instantiating the GramJob with the RSL GramJob job new GramJob gRSL job addListener this try Gram ping rmc catch Exception e System out print n Ping Failed e getMessage System out print n Requesting Job try job request rmc catch Exception e System out println Error e getMessage wait for job completion synchronized this try wait catch InterruptedException e System out println Error e getMessage public static void main String args System out println Starting GRAM amp GASS interactiv
10. globus gass cache The Globus Toolkit 2 2 provides command line tools globus gass cache as well as a C API that can be used to perform operations on the cache The operations are gt add Add the URL to the cache if it is not there If the URL is already in the cache increment its reference count delete Remove a reference to the URL with this tag if there are no more references remove the cached file gt cleanup tag Remove all references to this tag for the specified URL or all URLs if no URL is specified gt cleanup url Remove all tag references to this URL gt list List the contents of the cache The GASS cache is used when a job is submitted via the GRAM sub system The count entry in the RSL parameters allows control of how long the program will stay in the cache When forgotten the file will remain forever A common problem is to rerun a program in the cache after you have modified it locally amp executable https m0 itso maya com 20000 home globus Compile On the execution host the binary will be tagged as https m0 itso maya com 20000 home globus Compile If modified on MO it will not be modified on the cache Consequently the wrong program will be run on mO You can check the cache on the remote server with globus gass cache list Use globus gass cache clean up to remove all the entries in the cache The way to avoid this problem is to use count 1 in the RSL commands Count specifies tha
11. CICS 58 CoG 5 54 66 cog properties file 135 CoGs 134 command line interface 57 Common Component Architecture 67 CommonC library 282 Community Authorization Service 88 comodity grid kit CoG 66 compiler settings 55 computational grids 3 condition variables 106 Condor G 29 30 consumers 46 CORBA 5 66 credentials 7 137 D datacaches 73 data encryption 17 84 data grid 4 39 40 data input output 57 data management 5 9 14 25 75 163 considerations 28 data producer and consumer 46 data store 57 data topology 40 data topology graph 78 data types 79 Database Access and Integration DAI 99 Database Access and Integration Services 86 DFS 91 digital certificates 16 distinguished name 15 distributed by design 67 distributed by nature 67 DLLs 55 dumprsl 21 113 DUROC 18 21 dynamic libraries depedencies 281 Dynamically Updated Request Online Coallocator see DUROC 373 E encrypted sockets 171 European DataGrid Project 102 extended block mode 202 F factories 292 Federated Databases 99 federated databases 74 file staging 167 flavors 107 FLEXIm 64 G GAF4J 67 GASS 26 27 134 163 178 257 API 155 178 example Java 155 server 113 gatekeeper 18 21 GCE 66 General Public License 64 GFS 95 GIIS 23 25 125 GIS 14 23 Globus cache management 192 Globus common 106 Globus module 109 Globus Project 4 Globus Toolkit contents 5 overview 4 Version 2 2 4 Version 3 4
12. GLOBUS NULL purpose unknown server ez opts callback c function or GLOBUS NULL otherwise GLOBUS NULL or GLOBUS NULL otherwise if err GLOBUS SUCCESS cerr lt lt Error initializing GASS lt lt err lt lt lt lt endl exit 1 char gass server url globus gass transfer listener get base url listener cout lt lt we are listening on lt lt gass server url lt lt end wait until it is finished that means that the put requests to the URL https host dev globus gass client shutdown 1TS0 CB implements the symchronization mechanism by using a mutex and a condition variable callback Wait shutdown callback stop everything globus gass server ez shutdown listener globus module deactivate GLOBUS GASS SERVER EZ MODULE Checking credentials Here is a quick example of how to check if your credentials are valid in a C or C program These credentials are generated via the globus proxy init shell command include globus gss assist h include lt iostream gt main gss cred id t credential handle GSS C NO CREDENTIAL OM uint32 major status OM uint32 minor status major status globus gss assist acquire cred amp minor status GSS C INITIATE or GSS C ACCEPT amp credential handle Appendix B C C source code for examples 357 if major status GSS S COMPLETE cout lt lt unable to authenticate lt lt endl else
13. GLOBUSRUN_GASS_URL PWD GenerateDrawsGlobus sh argum ents TMP n V paramV subjobStartType loose barrier file stage in N GLOBUSRUN GASS URL PWD GenerateDrawsGlobus GenerateDrawsGlobus TMP file clean up GenerateDrawsGlobus TMP environment LD_LIBRARY_PATH V GLOBUS LOCATION lib done echo rs1 globusrun s o rs1 amp for monitoring we copy locally the Monitor files created on each compute nodes This file content the percentage of tested draws Each files is suffixes by the nodes number statusnum is actually the sum of all the percentage Monitor files devided by 100 When it equals the number of nodes that means that we have finished echo Monitoring rm f Monitor statussum 0 while statussum NodesNumber do echo 260 Enabling Applications for Grid Computing with Globus sleep 5 we poll every 5 seconds statussum 0 for i in 1oop do if s gass server i then contact cat gass server i globus url copy contact Monitor TMP file PWD Monitor i status cat Monitor i statussum status statussum echo Nodes i Monitor cat Monitor i fi done statussum statussum 100 done fStop the gassserver for i in loop do contact cat gass server i globus gass server shutdown contact done mds is the broker executable described in Broker example on page 127 It must be in the PATH because it is invoked by the SubmitGlobus sc
14. Job description in RSL language request_callback job contact url e provides Figure 5 2 Job submission using non blocking calls Note The documentation of the globus gram client API is available at http www unix globus org api c globus gram client html index html We only cover non blocking calls in this chapter as they are the more complicated from a programming perspective but often more desirable from an application perspective Non blocking calls allow the application to submit several jobs in parallel rather than wait for one job to finish before submitting the next Job submission The ITSO GRAM JOB class provided in itso gram job C on page 321 provides an asynchronous implementation in C of a job submission It is derived from ITSO CB ITSO GRAM JOB wraps C Globus GRAM API functions in its methods Its implementation is based on the C example available in Submitting a job on page 358 The first step is to create the GRAM server on the execution node that will monitor the status of the job and associate a callback with this job This is 118 Enabling Applications for Grid Computing with Globus achieved by calling the function globus_gram_client_callback_allow In the Submit method of the class ITSO GRAM JOB we find globus gram client callback allow itso gram job callback func void this amp callback contact The ITSO GRAM JOB object derived from ITSO CB
15. Secure char scheme https unsecure char scheme http globus_gass_transfer_listenerattr_t attr globus_gass_transfer_listenerattr_init amp attr scheme we want to listen on post 10000 globus_gass_transfer_listenerattr_set_port amp attr 10000 At this point the GASS server can be started The GLOBUS_GASS_SERVER_EZ_MODULE must already be activated The Wait method of ITSO_CB uses a mutex condition variable synchronization to ensure thread safety GASS server example Below is a GASS server example Example 7 18 Starting GASS server include globus_common h include globus_gass_server_ez h include lt iostream gt include itso_cb h main Never forget to activate GLOBUS module globus module activate GLOBUS GASS SERVER EZ MODULE Now we can start this gass server globus gass transfer listener t listener globus gass transfer requestattr t reqattr 7 GLOBUS NULL purpose unknown int err globus gass server ez init amp listener amp attr scheme 190 Enabling Applications for Grid Computing with Globus GLOBUS_NULL purpose unknown server ez opts callback c function or GLOBUS NULL otherwise if err GLOBUS SUCCESS cerr lt lt Error initializing GASS lt lt err lt lt lt lt endl exit 1 char gass server url globus gass transfer listener get base url listener cout lt lt we are listening on lt lt gas
16. String subCmd echo mOuser grid proxy init pwstdin try String cmd bin su c subCmd mOuser cmdResult doRun cmd catch IOException e System out print n doProxy e return cmdResult Chapter 8 Developing a portal 233 Submit grid application for execution Example 8 7 shows sample code to submit a job to the grid for execution The mdsHost is a fully qualified host name where the application will be submitted A valid grid host may be found from the output of the grid info search command The stage parameter is required if the application resides on the submission machine and not on the execution machine The jobld is returned after successful submission as shown in the tip below Tip The job ID is returned by the globus job submit command as shown below This job ID will be used to get the status and run the result as shown in the next section https al itso apache com 41418 2772 1049325984 Example 8 7 Sample code to submit a job from Web portal public String doSubmit String mdsHost String cmdResult null String subCmd globus job submit mdsHost stage home mOuser test sh try String cmd bin su c subCmd mOuser cmdResult doRun cmd catch IOException e System out print ln doSubmit e return cmdResult 0 Get application status The sample code in Example 8 8 shows how to retrieve the job status The jo
17. define HOWMANY 4 define WHITE 1 define BLACK HOWMANY 1 define XSIZE 8 define YSIZE 10 using namespace std class GAME char data int xsize int ysize int get int amp i int amp j return data i 1 j 1 xsize E int getl int amp i return data i 1 void set int amp i int amp j int who data i 1 j 1 xsize char who int available int col if getl col 0 return 0 int j for j ysizesget col j 0 j return j E bool test int i int j int amp col int amp line int amp player int k x y for int decalage 0 decalage HOWMANY decalaget int r 0 for k HOWMANY 1 k 1 k x i k decalage co y line j k decalage if x lt 1 Gexsize y gt ysize y lt 1 break E Appendix B C C source code for examples 337 if player get x y rt 1 h if r HOWMANY return true h return false h int calculate int i int j int amp col int amp line int res 0 k 0 x y for int decalage 0 decalage HOWMANY decalaget int r 0 for k HOWMANY 1 k 1 k x i k decalage col y line j k decalage if x lt 1 x gt xsize y gt ysize y lt 1 r 0 break h r get x y h Special if r HOWMANY r 2000 else if r HOWMANY BLACK r 1000 rest r h return res Ms public GAME GAME amp newgame xsize newgame getxsize ysize newgame getysize data char calloc xsize ysize l memcpy data new
18. lo void ITSO GRAM J0B SetRequestDone const char j job contact const_cast lt char gt j request_cb setDone void ITSO GRAM JOB Submit string res string rsl E failed false globus gram client callback allow itso gram job callback func void this amp callback contact int rc globus gram client register job request res c str rsl c_str GLOBUS_GRAM_PROTOCOL_JOB_STATE_ALL callback contact GLOBUS_GRAM_CLIENT_NO_ATTR itso gram job request callback void this if rc 0 if there is an error printf TEST gram error d s n rc translate the error into english globus gram client error string rc return void ITSO GRAM JOB Wait ti request_cb Wait ITSO CB Wait Free up the resources of the job contact as the job is over and the contact is now useless globus gram client job contact free job contact request cb Continue ITSO CB Continue void ITSO GRAM JOB Cancel int rc printf tTEST sending cancel to job manager n if rc globus gram client job cancel job contact 0 printf tTEST Failed to cancel job n printf tTEST gram error d s n Appendix B C C source code for examples 323 rc globus_gram_client_error_string rc else printf tTEST job cancel was successful n h void ITSO GRAM JOB SetFailed failed true bool ITSO GR
19. low to high efforts Data easily separable gt some solvable data interdependenc ies gt data inseparable Small amount of I O data per job gt large amount of data handled by single jobs Simple job topology job node data gt complex job topology Simple data topology data job node gt complex data topology High upper limit in scalability graph gt low upper limit All permissive gt all restrictive Appendix A Grid qualification scheme 303 Qualification criteria Weight factors H M L Com ment Range Effort Skills show low to high stoppers efforts special care base values Billing Not required gt service simple direct billing gt complex billing including thrid parties Single Not required gt user standard UI gt interface integrated common UI 304 Enabling Applications for Grid Computing with Globus C C source code for examples This appendix contains C C source code for various modules that were referenced throughout this publication It should be noted that this source code is provided as is Though it was compiled and executed in our specific environment it has not been thoroughly tested and is meant to provide guidance and examples of how to accomplish certain tasks Copyright IBM Corp 2003 All rights reserved 305 Globus API C wrappers The following examples show some C wrappers for some common Globus services IT
20. 444444444444444444444444444444444 we need to run this script to load all correct environment variables The configure script will failed otherwise 44444444444444444444444444444444 bash profile tar zxf commoncpp2 1 0 8 tar gz d tmp mkdir tmp cd commoncpp2 1 0 8 44444444444444444444444444444444444444444 We use HOME instead of here because make install will failed to create directory otherwise 44444444444444444444444444444444444444444 configure prefix HOME tmp amp amp make install 4444444444444444444444 Stay clean 44444444444444444444 44 rm fr commoncpp2 1 0 8 The dynamic library is installed in tmp lib on the remote host We use the LD LIBRARY PATH variable under the Linux operating system to specify the location of the dynamic libraries to the HelloServer executable This way we are not intrusive to the remote system we do not have to be root and install a binary on the system and this library will not affect applications other than ours LD LIBRARY PATH is set automatically during the GRAM invocation by using an environment declaration in the RSL string amp executable https m0 itso maya com 20000 home globus HelloServer environment LD_LIBRARY_PATH HOME tmp lib count 1 arguments 1804289383 t0 The CommonC library source is stored locally in tmp in mO We use the ITSO GASS TRANSFER class to transfer the file from one GridFTP server to the remote serve
21. Avaki Data Grid provides a solution for sharing files across Wide Area Networks Its two main features are gt It provides an NFS interface for applications that can therefore transparently access files stored in the Avaki files system For security reasons the Avaki Data Grid is usually mounted locally NFS client NFS client NFS client I I I Avaki DataGrid Avaki DataGrid Avaki DataGrid Access Server Access Server Access Server Avaki Data Grid Figure 4 8 Accessing Avaki Data Grid through NFS locally mounted file system Bycreating an Avaki share you can map local files on a node into the Avaki Data Grid This way the files become available to all nodes connected to the Avaki Data Grid The synchronization between the local files and their Avaki DataGrid copies occurs periodically based on a configuration option For example every three minutes 92 Enabling Applications for Grid Computing with Globus NFS client NFS client I Avaki DataGrid Avaki DataGrid Access Server Access Server local cache copy Avaki Data Grid am logical view Avaki Share Server peri synchronization Figure 4 9 Avaki share mechanism Avaki also provides complete user management and Access Control List policies For applications Avaki maps Avaki user authorization with local operating syst
22. Job Finished on https t0 itso tupi com 58421 7869 1047519211 Job Finished on https t3 itso tupi com 55121 29325 1047519244 Job Finished on https t3 itso tupi com 55117 29324 1047519244 Chapter 9 Application examples 12345678 9 3 Hello World example Let us consider the following cases of client server applications or Web applications Video streaming Game serving File downloading Etc YYY Yy A classical approach for providing a scalable solution is to distribute the application workload across a set of distributed servers that run the same application An edge server or network dispatcher or front end server is the entry point for the application but does not run the application itself The other servers located on the same LAN handle the workload and answer the client application or client browser 278 Enabling Applications for Grid Computing with Globus servers farm Figure 9 6 Cluster model A grid approach extends the concept of clustering by enabling the deployment of servers not only on the same LAN but on a WAN infrastructure The edge server becomes a broker server that will start the applications on remote servers to handle the workload The broker can use different criteria to manage this workload Use the server located at the nearest location from the client Use servers according a certain service level agreement with the customer Use new servers provided by a resou
23. Parallel data transfer using multiple TCP streams to improve the aggregate bandwidth It supports the normal file transfer between a client and a server It also supports the third party data transfers between two servers gt Striped data transfer that partitions data across multiple servers to further improve aggregate bandwidth gt Partial file transfer that allows the transfer of a portion of a file gt Reliable data transfer that includes fault recovery methods for handling transient network failures server outages and so on The FTP standard includes basic features for restarting failed transfer The GridFTP protocol exploits these features and substantially extends them gt Manual control of TCP buffer size allows achieving maximum bandwidth with TCP IP The protocol also has support for automatic buffer size tuning gt Integrated instrumentation The protocol calls for restart and performance markers to be sent back GridFTP server and client Globus Toolkit provides the GridFTP server and GridFTP client which are implemented by the in ftpd daemon and by the globus ur1 copy command and related APIs respectively They support most of the features defined for the GridFTP protocol 26 Enabling Applications for Grid Computing with Globus The GridFTP server and client support two types of file transfer Standard and third party The standard file transfer is where a client sends or retrieves a file to from the remote
24. Tuecke Cluster Computing 1 1 95 107 1998 ftp ftp globus org pub globus papers cc security pdf Online resources These Web sites and URLs are also relevant as further information sources Globus http www globus org GSI Enabled OpenSSH visit http grid ncsa uiuc edu ssh Globus GASS http www fp globus org gass BSD Licensing http www opensource org licenses bsd 1icense php MIT Licensing http opensource org licenses gpl license php Apache Software license http www opensource org licenses apachepl php Open source Initiative license information http opensource org docs certification mark php Lesser General Public License http www opensource org licenses 1lgpl license php GNU Public License http www gnu org copyleft gpl html IBM Public License http www opensource org licenses ibmpl php FLEXIm supported license models http www globetrotter com flexlm lmmodels sthm Related publications 369 gt FLEXIm general information http www globetrotter com flexlm flexlm shtm Tivoli License Manager http www ibm com software tivoli products license mgr gt IBM License Use Management http www ibm com software is lum gt Platofrm Global License Broker http www platform com products wm glb index asp gt Globus Commodity Grid toolkts CoGs http www globus org cog gt Grid Computing Environment GCE http ww globus org research development environments htm gt Grid E
25. as an argument to SmallBlueslave which will load the current value and therefore will recreate the same environment that exists in SmallBlueMaster By using the GRAM and GASS subsystems all the results of the execution nodes will be output to the same file eval on the master node Communication is accomplished 1 By a local GASS server started on the master node and listening on port 10000 2 By the GASS servers started on each execution node by the GRAM which will map standard input and output to remote files 266 Enabling Applications for Grid Computing with Globus The following RSL command describes this process amp executable smallblueslave arguments lt tested column gt stdout https lt masternode gt 10000 lt 1ocaldir gt eval stdin https lt masternode gt 10000 lt localdir gt GAME count 1 GRAM server Current del LI LL Current column tested local GASS server eval P ccce smallblueslave smallbluemaster can read each value for each position and takes the best one Figure 9 5 How to transfer an object via GRAM and GASS The local GASS server started by SmallBlueMaster transparently provides access to the eval and GAME file to the remote execution nodes via GRAM and the associated GASS server It arbitrarily listens on port 10000 Two functions StartGASSServer and StopGASSServer wrap
26. cout lt lt that s fine lt lt endl Submitting a job Here is a small C example that provides a skeleton for submitting a job ina C program The examples in this publication use the ITSO_GRAM_JOB C class which is basically a C wrapper to this C skeleton include lt stdio h gt include globus gram client h include lt globus_gram_protocol_constants h gt It is the function used when the remote Job Manager needs to contact your local program to inform it about the status of the remote program It is passed along with the the job_request to the remote computer static void callback func void user callback arg char job contact int state int errorcode N Setting up the GRAM monitor The monitor will stall this program until the remote program is terminated either through failure or naturally Without the monitor this program would submit the job and end before the job completed The monitor works with a lock Only one function may access the Done flag at a time so in order to access it the gram must set a lock on the monitor variable so that nothing else may access it then change it and finally unlock it This is seen later in the code 0k F F F F N This whole structure is the monitor typedef struct globus mutex t mutex globus cond t cond globus bool t done my monitor t BRR RR RRR RRR KERR ER ERK RR KE RRR EKER KR ERK KEK EKER ER ERE
27. gt gt guaraniFiles done 3 Register the collection globus replica catalog password password collection create FileList 4 Register the two locations and their file list globus replica catalog password password location t0 Tupi Storage create gridftp t0 itso tupi com home globus storage tupiFiles 210 Enabling Applications for Grid Computing with Globus globus replica catalog password password location g0 Guarani Storage create gridftp g0 itso tupi com home globus storage guaraniFiles 5 Register each of the logical files with their size globus replica catalog password password logicalfile filel create 100000 globus replica catalog password password logicalfile file2 create 200000 globus replica catalog password password logicalfile file3 create 300000 globus replica catalog password password logicalfile file4 create 400000 globus replica catalog password password logicalfile file5 create 500000 We can now perform a few requests 1 Search for all locations that contain file4 and file5 a Create a file FilesToBeFound that contains the files we are looking for for i in file4 file5 do echo i FilesToBeFound done b Perform the request globus replica catalog password password collection find locations FilesToBeFound uc Then you should receive the following output filename file4 filename file5 uc gridftp g0 i
28. provides the necessary methods Wait waits for the completion of the operation setDone sets the status of the operation to done The done attribute is actually set to true IsDone retrieves the state of the operation done or not and checks the value of the done attribute Continue resets the value of the attribute done to false Note In the C C publication examples an ITSO CB object as well as a C callback function that will call its setDone method must be provided to the asynchronous globus functions They take the ITSO CB object as well as the callback function pointer as arguments The C function is declared as static and must be reentrant and is only used to call the ITSO CB object methods 5 2 Submitting a job Before showing programming examples let us briefly review the options that are available when a job is submitted The easiest way to do this is to look at the commands that are available Once you understand the types of things you might do from the command line it will help you better understand what you must do programmatically when writing your application 110 Enabling Applications for Grid Computing with Globus 5 2 1 Shells commands The Globus Toolkit provides several shell commands that can be easily invoked by an application In this case the application may be a wrapper script that launches one or more jobs The commands that can be used to launch a job include
29. r t2 amp executable bin MyProg arguments 1 count 1 file stage out 0utputFileGenerated GLOBUSRUN GASS URL tmp RetrievedFile GLOBUSRUN GASS URL is automatically expanded to the URL of the local GASS server started when globusrun is issued This GASS server is started locally by using the s option and is used when access to files stored on the submission node is requested Example 7 2 on page 168 is a similar example but the output file is put on a GridFTP server running on b1 Chapter 7 Using Globus Toolkit for data management 167 Example 7 2 Using GridFTP in RSL globusrun o r t2 amp executable bin MyProg arguments 1 count 1 file stage out 0utputFileGenerated gsiftp b1 tmp RetrievedFileOnb1 The file_stage_in directive performs the opposite task It can move data from one location to the execution node In the following examples the FileCopiedOnTheExecutionNodes is copied into the home directory of the user used for the job execution on the execution node and used by the Exec program The second example uses the local GASS server started by globusrun Example 7 3 Staging files in globusrun o s r al amp executable Exec arguments 1 count 1 file stage in gsiftp m0 tmp files on storage server FileCopiedOnTheExecutionNodes globusrun o s r tl amp executable Exec arguments 1 count 1 file stage in GLOBUSRUN GASS URL local file on the submission node FileCopiedOnT
30. value My Application Status gt lt TD gt lt TD width 20 gt lt INPUT type submit name data value My Application Results gt lt TD gt lt TD width 20 gt lt TD gt lt TD width 20 gt lt TD gt lt TD width 20 gt lt INPUT type submit name logout value Logout gt lt TD gt 230 Enabling Applications for Grid Computing with Globus Tip Determine which button is pressed String getresult String getstatus String logout try Which button selected getresult req getParameterValues result getstatus req getParameterValues status logout req getParameterValues logout if submit null amp amp submit length gt 0 submitApplication submit Application else if getresult null amp amp getresult length gt 0 getResult get application run results else if getstatus null amp amp getstatus length gt 0 getStatus get application status else if logout null amp amp logout length gt 0 doLogout logout else invalidInput catch Throwable theException uncomment the following line when unexpected exceptions are occuring to aid in debugging the problem theException printStackTrace throw new ServletException theException Tip How to redirect to an html page private void doLogout try RequestDispatcher rd getServletContext getRequestDispatcher login html rd forward req res catch java
31. xargs t2 itso tupi com tl itso tupi com al itso apache com In the next example we look for all machines that have a Pentium processor and that either runs at a frequency greater than 500 Mhz or has more than 5 Gb of available diskspace ldapsearch x p 2135 h m0 b mds vo name maya o grid s sub amp Mds Os name Linux Mds Cpu model Pentium Mds Cpu speedMHz gt 500 Mds Fs Total sizeMB gt 5000 Mds Host hn awk Mds Host hn print 2 xargs al itso apache com a2 itso apache com b2 itso bororos com d2 itso dakota com dl itso dakota com t2 itso tupi com t3 itso tupi com tl itso tupi com t0 itso tupi com c2 itso cherokee com cl itso cherokee com 126 Enabling Applications for Grid Computing with Globus Graphical tools There are a variety of GUI tools can be used to browse the Globus MDS server Under Linux a graphical client named gq permits easy browsing If not available on your distribution it can be downloaded from the following URL http biot com gq a TEN File Filters Help E 88 73 i52 JLP Ldap Mds Cpu Total Free 1minX100 064 E itso Mds Vo name local o Grid Mds Cpu Total Free Sminx100 087 E Mds Vo name maya o Grid Mds Cpu Total Free 15minX100 098 Mds Vo name apache Mds Vo name cherokee EF Mds Vo name tupi Mds Fs Total sizeMB 5674 Mds Host hn t2 itso tupi com Mds Fs Total count 3 ds Host hn t3 itso tupi com SR 1693 lds Host
32. 1 97 Edition Before joining IBM in 1989 he worked as an application and system developer for a software vendor of CIM ERP systems Norbert holds a Masters degree in mathematics from the University of Technology Aachen Germany and developed their evaluation systems for electron microscopes He is currently studying for an MBA at Henley Management School He has written extensively on application architecture considerations Candice Gilzean is a Software Engineer for the Grid Computing Initiative in Austin Texas She has 2 5 years of experience for IBM Global Services She holds a BS degree in Computer Science with a minor in Math from Texas Tech University Her areas of expertise include Grid Computing Net programming and AIXG She has written extensively on job flow java cog and Globus ToolKit Version 3 Jean Yves Girard is an IT Specialist working in the Grid Design Center for e business on demand IBM Server Group located in France in Montpellier He has been with IBM for six years and has been involved with Grid Computing since March 2002 and Linux solutions for three years He holds a degree of l ve ing nieur from cole Centrale Paris France His areas of expertise include Linux operating system HPC computing Grid technologies and Web Services Roman Strachowski is an IT Specialist working in the Sales Operations Team IBM Sales amp Distribution Group located in Zurich Switzerland He has been with IBM for five yea
33. 25 information services 5 14 22 290 considerations 25 infrastructure components 14 infrastructure considerations 13 instances 292 interactive jobs 53 interconnect 5 inter process communication 22 33 56 intra grids 3 introduction 1 ITSO broker example 327 ITSO_CB 268 ITSO_CB callback example 315 ITSO_GASS Transfer example 306 ITSO_GLOBUS_FTP_CLIENT example 311 ITSO_GRAM_JOB 118 ITSO_GRAM_JOB example 316 ITSO_GRAM_JOB object 119 J Java 5 53 66 133 232 JavaCoG 133 JNDI 141 job 45 job criteria 51 job dependencies 54 job flow 11 45 job management 10 22 job manager 18 21 job scheduler 9 job submission 117 118 123 251 job topology 56 jobs 45 JVM 40 K Kerberos 26 knock out criteria 68 L LD_LIBRARY_PATH 260 282 LDAP 8 23 67 128 143 LDAP query 125 Idapsearch 25 125 126 Idd command 108 LDIF 290 Lesser General Public License 64 LGPL 64 libc 106 libraries 108 license agreement 62 License Broker 66 license management 64 License Manager 65 license models 62 License Use Management 65 life cycle management 5 6 load balancing 31 considerations 32 locking 75 locking management 106 loose coupling 49 Lottery example 349 M Makefile 106 Makefile example 108 MCAT 101 MDS 8 14 22 25 33 105 134 MDS example Java 141 memory size 55 Message Passing Interface 66 message queues 57 meta scheduler 9 metadata 94 101 mirroring 87 MIT 63 m
34. 4 Data management considerations 99 The project is in place to implement a general grid interface for accessing grid data sources like relational database management systems and XML repositories through query languages like SQL XPat and XQuery XQuery is a new query language like SQL and under draft design in the W3C The software deliverables of the OGSA DAI project will be made available to the UK e Science community and will also provide the basis of standards recommendations on grid data services that are put forward to the Global Grid Forum through the DAIS working group For more information see http umbriel dcs gla ac uk NeSC general projects 0GSA_DAI Spitfire Spitfire is a project of the European DataGrid Project It provides a grid enabled middleware service for access to relational databases providing a uniform service interface data and security model as well as network protocol Spitfire uses the Globus GSI authentication and thus can be easily integrated in an existing Globus infrastructure Spitfire is currently using MySQL and PosrtGreSQL databases and the Web services alpha release should be available soon Currently it consists of the Spitfire Server module and the Spitfire Client libraries and command line executables Client side APIs are provided for Java and C for the SOAP enabled interfaces The C client is auto generated from its WSDL description using gSOAP which is an open source implementation proto
35. 5 289 globus_gass_server_ez API 188 globus_gass_transfer API 187 globus_gram_client API 118 globus_io 169 globus_module_activate 109 globus_module_deactivate 109 globus job run 21 111 globus job submit 112 globus makefile header 108 globusrun 18 19 113 globus url copy 26 GPFS 91 GPL 64 GrADS 67 GRAM 18 27 105 134 138 290 GRAM example Java 139 Graphical Tools 127 grid components 6 computational 3 data 4 infrastructure considerations 13 overview 3 scavenging 4 types 3 Grid Access to Secondary Storage see GASS Grid Application Development Software 67 Grid Application Examples 246 Grid Application Framework for Java 67 grid applications 45 Grid File Transfer Protocol see GridFTP Grid Index Information Service see GIIS Grid Information Service see GIS Grid Resource Allocation Manager see GRAM Grid Resource Information Service see GRIS Grid Security Infrastructure see GSI grid types data grid 40 GridFTP 9 26 134 195 290 client server 151 example Java 148 grid info search 125 grid proxy init 15 134 GriPhyn Project 102 GRIS 24 25 GSI 7 14 15 26 170 290 GSI socket 173 GSI Enabled OpenSSH 15 16 53 246 369 gSOAP 291 H hardware devices 55 header files 107 heartbeat monitoring 38 Hello World example 278 341 374 Enabling Applications for Grid Computing with Globus HTML 58 HTTP 58 l IBM Grid Toolbox 67 ID administration 16 ID mapping 17 index service 293 information providers 23
36. 7 Access Control System There is no component in the Globus Toolkit that provides an enforcement of Access Control List policies Each administrator by configuring the grid mapfile stored on its resources and file s user access rights can allow or disallow the remote job execution on its resources under a certain user ID It can only enforce local policy A project still under development the Community Authorization Service CAS should provide such access control The administrator of a resource server grants permissions on a resource to the CAS server The CAS server grants fine grained permissions on subsets of the resources to members of the community For more information see the Community Authorization Service CAS site http ww globus org security CAS 4 2 8 Peer to peer data transfer Peer to peer systems and applications are distributed systems without any centralized control or hierarchical organization Each node of the peer to peer can be both client and server For example when a client begins to download a file from a server it allows other clients to start downloading the same file from its own storage 88 Enabling Applications for Grid Computing with Globus There is no peer to peer solution currently provided by the Globus Toolkit However a group at the Globus Forum is working on this domain relation of OGSA Globus and Peer2Peer A complete report should be provided for GGF8 or more information see the follo
37. CPU cycles and other resources Owners of the desktop machines are usually given control of when their resources are available to participate in the grid Data grid A data grid is responsible for housing and providing access to data across multiple organizations Users are not concerned with where this data is located as long as they have access to the data For example you may have two universities doing life science research each with unique data A data grid would allow them to share their data manage the data and manage security issues such as who has access to what data Another common distributed computing model that is often associated with or confused with grid computing is peer to peer computing In fact some consider this another form of grid computing For a more detailed analysis and comparison of grid computing and peer to peer computing refer to On Death Taxes and the Convergence of Peer to Peer and Grid Computing by lan Foster Adriana lamnitchi This document can be found at http people cs uchicago edu anda papers foster grid vs p2p pdf 1 2 Globus Project The Globus Project is a joint effort on the part of researchers and developers from around the world that are focused on the concept of grid computing It is organized around four main activities Research Software Tools Testbeds Applications YYY Yy You can get more information about the Globus Project and their activities at http www globus org
38. Chapter 6 Programming examples for Globus using Java 141 private int scope SearchControls SUBTREE SCOPE private int ldapVersion 3 private int sizeLimit 0 private int timeLimit 0 private boolean ldapTrace false private String saslMech private String bindDN private String password private String qop auth could be auth auth int auth conf public MyGridInfoSearch The org globus mds gsi common GSIMechanism method verifies that the GSI security credentials are valid and sets the context The search method below performs two functions Authentication and searching It calls the method GSIMechanism Example 6 9 GridlnfoSearch example 2 of 4 Search the ldap server for the filter specified in the main function private void search String filter Hashtable env new Hashtable String url 1dap hostname port env put java naming ldap version String valueOf ldapVersion env put Context INITIAL CONTEXT FACTORY DEFAULT CTX env put Context PROVIDER URL url if bindDN null env put Context SECURITY PRINCIPAL bindDN use GSI authentication from grid proxy init certificate saslMech GSIMechani sm NAME env put javax security sasl client pkgs org globus mds gsi jndi env put Context SECURITY AUTHENTICATION saslMech env put javax security sasl qop qop LdapContext ctx null 142 Enabling Applications for Grid Computing with Globus crea
39. Compile count 1 start app server on t0 amp executable https m0 itso maya com 20000 home globus JYCode HelloServer environment LD_LIBRARY_PATH HOME tmp lib count 1 arguments 1804289383 t0 Contact on the server https t0 itso tupi com 57701 3673 1047501872 Staging file in on https t0 itso tupi com 57701 3673 1047501872 Job Finished on https t0 itso tupi com 57701 3673 1047501872 binding for m0 itso maya com 4096 You can now start the client from another node You do not need to generate a valid proxy john a0 john HelloClient m0 Ticket 1804289383 Hostname t0 Hello World On mo you should see the connection request The connection is actually handled by the application server tO Chapter 9 Application examples 287 accepting from m0 itso maya com 54642 creating session client object 9 4 Summary This chapter has described three different application examples that demonstrate various techniques and concepts of the Globus Toolkit and related capabilities These samples were purposely kept simple in that they did not include a lot of error checking or other logic that should be included in a robust business application 288 Enabling Applications for Grid Computing with Globus 10 Globus Toolkit V3 0 This publication is primarily based on Globus Toolkit V2 2 However by the time you read this Globus Toolkit Version 3 will likely be available at least as beta code Though many of
40. Data Grid API globus_replica_manager globus_gass_copy v v globus gass transfer globus gass ftp client v globus_gass_ftp_control v globus replica catalog v AA globus io GSI PKI 34 Idap client globus common Figure 7 1 Data management interfaces Figure 7 1 provides a view of the various modules associated with data management in the Globus Toolkit and how they relate to one another These modules are described in more detail throughout this chapter 164 Enabling Applications for Grid Computing with Globus 7 1 Using a Globus Toolkit data grid with RSL The Global Access to Secondary Storage is a simple multi protocol transfer software integrated with GRAM The purpose of GASS is to provide a simple way to enable grid applications to securely stage and access data to and from remote file servers using a simple protocol independent API GASS features can easily be used via the RSL language describing the job submission By using URLs to specify file names RSL permits jobs to work on remotely stored files GASS transparently manages the data movement Using https or http prefixes in a URL connects to a remote GASS server and using gsiftp as a prefix connects to gsiftp servers All files specified as input parameters are cop
41. Draft Internet X 509 Public Key Infrastructure Proxy Certificate Profile found at http www ietf org internet drafts draft ietf pkix proxy 03 txt gt MDS 2 2 User s Guide found at http www globus org mds mdsusersguide pdf The Open Grid Services Architecture and Data Grids found at http aspen ucs indiana edu CCPEwebresource c600gridkunszt c600FINAL gt GridServices_DataGridv3 pdf The Physiology of the Grid An Open Grid Services Architecture for Distributed Systems Integration found at http ww globus org research papers ogsa pdf A Resource Management Architecture for Metacomputing Systems found at ftp ftp globus org pub globus papers gram97 pdf RFC 3280 Internet X 509 Public Key Infrastructure Certificate and Certificate Revocation List CRL Profile found at http ww ietf org rfc rfc3280 txt Web Services Conceptual Architecture WSCA 1 0 found at http www ibm com software solutions webservices pdf WSCA pdf Web Service Description Language WSDL 1 1 found at http www w3 org TR wsdl 368 Enabling Applications for Grid Computing with Globus A Security Architecture for Computational Grids Foster C Kesselman G Tsudik S Tuecke Proc 5th ACM Conference on Computer and Communications Security Conference pp 83 92 1998 ftp ftp globus org pub globus papers security pdf Managing Security in High Performance Distributed Computing Foster N T Karonis C Kesselman S
42. For this publication we present most of our information in the context of the Globus Toolkit The Globus Toolkit provides software tools to make it easier to build computational grids and grid based applications The Globus Toolkit is both an open architecture and open source toolkit At the time of this writing the current version of the Globus Toolkit is Version 2 2 Version 3 of the toolkit is currently in alpha release and is expected to be 4 Enabling Applications for Grid Computing with Globus available shortly However the examples and information we provide are mostly based on the 2 2 version 1 2 1 Globus Toolkit Version 2 2 The Globus Toolkit V2 2 provides Asetofbasic facilities needed for grid computing Security Single sign on authentication authorization and secure data transfer Resource Management Remote job submission and management Data Management Secure and robust data movement Information Services Directory services of available resources and their status Application Programming Interfaces APIs to the above facilities gt C bindings header files needed to build and compile programs In addition to the above which are considered the core of the toolkit other components are also available that complement or build on top of these facilities For instance Globus provides a rapid development kit known as Commodity Grid CoG which supports technologies such as Java Python
43. GASS COPY URL MODE GASS source gass attr globus gass transfer requestattr t globus libc malloc sizeof globus gass transfer requestattr t globus gass transfer requestattr init source gass attr source url getScheme globus gass copy attr set gass amp source gass copy attr source gass attr globus gass transfer requestattr set file mode Source gass attr GLOBUS GASS TRANSFER FILE MODE BINARY globus gass copy attr set gass amp source gass copy attr source gass attr E ti void ITSO GASS TRANSFER setDestination GLOBUS URL amp dest url globus gass copy attr init amp dest gass copy attr dest url mode dest url getMode if dest url mode GLOBUS GASS COPY URL MODE FTP dest ftp attr globus ftp client operationattr t globus libc malloc sizeof globus ftp client operationattr t globus ftp client operationattr init dest ftp attr globus gass copy attr set ftp amp dest gass copy attr dest ftp attr else if dest url mode GLOBUS GASS COPY URL MODE GASS globus gass transfer requestattr t globus libc malloc dest gass attr sizeof globus gass transfer requestattr t globus gass transfer requestattr init dest gass attr dest url getScheme globus gass copy attr set gass Sdest gass copy attr dest gass attr globus gass transfer requestattr set file mode dest gass attr GLOBUS GASS TRANSFER FILE MODE BINARY globus gass copy attr set gass 8dest gass copy attr de
44. Globus Toolkit 2 2 shell commands can transparently use the GridFTP protocol whenever the URL used for a file begins with gsiftp 7 4 1 GridFTP examples The following example copies the jndi file located on mO itso maya com to the host g2 itso guarani com Note that this command can be issued on a third machine such as t2 itso tupi com globus url copy gsiftp m0 jndi 1 2 1 zip gsiftp g2 jndi 1 2 1 zip The following example executes on g2 itso guarini com a binary that is retrieved from g1 itso guarani com This command could be issued from t3 itso tupi com globus job run g2 gsiftp g1 bin hostname A grid enabled application needs to use the GridFTP API to be able to transparently use Globus Toolkit 2 data grid features This API is detailed in Globus GridFTP APIs 7 4 2 Globus GridFTP APIs This section discusses the APIs that can be used with GridFTP Skeletons for C C applications globus module activate GLOBUS FTP CLIENT MODULE must be called at the beginning of the program to activate the globus ftp client module Within the globus ftp client API all FTP operations require a handle parameter Only one FTP operation may be in progress at once per FTP handle The type of this handle is globus ftp client handle t and must be initialized using globus ftp client handle init The properties of the FTP connection can be configured using another handle of type globus ftp client handleattr t that also must be i
45. Grid Computing with Globus see javax servlet http HttpServlet void javax servlet http HttpServletRequest javax servlet http HttpServletResponse public void doPost HttpServletRequest req HttpServletResponse resp throws ServletException IOException performTask req resp public void performTask HttpServletRequest request HttpServletResponse response throws ServletException Add your authentication code here If authentication successful System out printIn Login forwarding to welcome page try RequestDispatcher rd getServletContext getRequestDispatcher welcome html rd forward request response catch java io IOException e System out printIn e If authentication failed try RequestDispatcher rd getServletContext getRequestDispatcher unsuccessfulLogin html rd forward request response catch java io IOException e System out printiIn e The file welcome html produces the welcome screen From here the user may select a grid application from the list and submit Clicking Submit Grid Application button sends control to the application servlet The selected grid application is identified in the servlet and appropriate routines are invoked as shown in Figure 8 5 on page 222 Chapter 8 Developing a portal 221 welcome html Figure 8 5 Simple grid portal application submit flow The
46. JobID null To Start the GASS Server private void startGassServer try gServer new GassServer 0 gURL gServer getURL catch Exception e System out print n GassServer Error e getMessage gServer registerDefaultDeactivator System out printIn GassServer started Starting the GASS server and getting the server URL will provide us with the ability to retrieve data later By registering the default deactivator we can destroy the GASS server before we exit the program Example 6 31 Batch GASS example 2 of 4 Method called by the GRAMJobListener public void statusChanged GramJob job 156 Enabling Applications for Grid Computing with Globus System out print n Job job getIDAsString Status job getStatusAsString private synchronized void runJob RSL String to be executed String RSL amp executable bin 1s directory bin arguments 1 String gRSL null Resource Manager Contact String rmc t2 itso tupi com gRSL RSL stdout x gass cache GLOBUS_GRAM_JOB_CONTACT stdout test stderr x gass cache GLOBUS GRAM JOB CONTACT stderr test Instantiating the GramJob with the RSL GramJob job new GramJob gRSL job addListener this Our RSL string that will execute an application needs to be modified so the standard out and error is written to the GASS server Example 6 32 Batch GASS example 3 of 4 System out pr
47. KK KKK KK KR KEKE RE KEKE KEKE KKK ERK Ke e kke ERE F F F F HF X globus module activate GLOBUS FTP CLIENT MODULE globus mutex init amp lock GLOBUS NULL globus cond init amp cond GLOBUS NULL globus ftp client handle init amp handle GLOBUS NULL BR RRRR ERE RRR EKER EKER KK ERK KR ERK KR RK KEKE KER KK RR KEKE RK KERR KEE KERR KEKE globus_ftp_client_put starts the protocol exchange on the control channel Note that this does NOT start moving data over the data channel RAK KR KKK RR KK KR KK ERK KK EK KK RK KKK KKK RK ERR RA RARA KARA RARA ARA REE EERE done GLOBUS_FALSE result globus_ftp_client_put amp handle dst GLOBUS_NULL GLOBUS_NULL done_cb 0 if result GLOBUS SUCCESS globus_object_t err Chapter 7 Using Globus Toolkit for data management 199 err globus_error_get result fprintf stderr 5s globus object printable to string err done GLOBUS TRUE else int rc EEE K k k e k RA AAA AA AAA AAA ARA RA RK KEKE KEKE KKK KER AAA RARA RE KERR ERK F F F F F F This is where the data movement over the data channel is initiated You read a buffer and call register_write This is an asynch call which returns immediately When it is finished writing the buffer it calls the data callback defined above which reads another buffer and calls register_write again The data callback will also indicate when you have hit eof Note that eo
48. LI gt lt UL gt lt P gt You may now submit an application to the grid lt BR gt Please note this portal is designed for demonstration purposes only lt P gt lt TD gt lt TR gt lt TBODY gt lt TABLE gt lt FORM gt lt BODY gt lt HTML gt The Application java servlet code is shown in Example 8 4 on page 225 Tip Determine which application was selected private void submitApplication if appselect 0 equals weather submitWeather else if appselect 0 equals gene submitGene else if appselect 0 equals test submitTest else if appselect 0 equals demo submitDemo else invalidSelection 224 Enabling Applications for Grid Computing with Globus Tip Determine if the Submit Grid Application button was checked String submit String appselect try Which button selected submit req getParameterValues submit Which application was selected appselect req getParameterValues appselect if submit null amp amp submit length gt 0 submitApplication submit Application else invalidInput catch Throwable theException uncomment the following line when unexpected exceptions are occuring to aid in debugging the problem theException printStackTrace throw new ServletException theException Example 8 4 Simple grid portal Application java servlet code 5630 A23 5630 A22 C Copyright IBM Corporation 2003 A
49. RAAA ARA RAR AA AAA KR ERR EERE RK class MONITOR globus mutex t mutex globus cond t cond globus object t err globus bool t Use err globus bool t done public MONITOR globus mutex init amp mutex GLOBUS NULL globus cond init amp cond GLOBUS NULL done GLOBUS FALSE use err GLOBUS FALSE MONITOR globus mutex destroy amp mutex globus cond destroy amp mutex void setError globus object t error use err GLOBUS TRUE err globus object copy error void setDone globus mutex lock amp mutex done GLOBUS TRUE globus cond signal amp cond globus mutex unlock amp mutex void Wait Chapter 7 Using Globus Toolkit for data management 183 globus_cond wait amp cond amp mutex void Lock globus mutex lock amp mutex void UnLock globus mutex unlock amp mutex bool IsDone return done h h f E FEAR AAA ARA AAA AA RARA AA AA AAA KKK KR ERK RARA RARA ARA AAA AAA RATA callback calls when the copy operation has finished globus gass copy register handle to url takes this function as a parameter In C a class method cannot be passed as a parameter to this function and we must use an intermediate C funtion that will call this method Consequently the object is used as the callbback argument so that this C function knows which method it must call monitor gt setDone f Fej kk k keke k ke eke e e e ke e he ke e ke e e he h
50. RR eke ER EKER KERR KK RRR ARR ARR RARA For a mote complete example see globus url copy c RRR KKK KKK RK KERR KKK RK ERR EERE KEKE KEKE KEKE KER f BRRRRRRR RRR RRR ke RRR ERR KERR KK RRR KR KR KK ERK EKER ER ERK RR KK ERK KER ER ERR EERE RK GLOBUS FILE is a class that acts as a wrapper to the globus io handle t globus io handle t is taken as a parameter to globus gass copy register handle to url GLOBUS URL is taken as a parameter to startTransfer method of the GASS TRANSFER class f EE RAR AAA AAA AAA AA AAA A AAA AAA AA RRR KK AA ARA RA ARA RA RARA AAA AAA AA AAA KR ERR EERE RK class GLOBUS FILE globus io handle t io handle int file fd public GLOBUS FILE GLOBUS FILE char filename io handle globus io handle t globus libc malloc sizeof globus io handle t file fd open filename 0 RDONLY Globus function that converts a file descriptor into a globus io handle globus io file posix convert file fd GLOBUS NULL io handle P GLOBUS FILE close file fd globus libc free io handle globus io handle t get globus io handle return io handle bs E EEEE AAA k kek k ke eke e AAA e he ke AAA AA RRR KE KR KK ERK EKER KK Ae e He Ae He He KERR She ke he Ske e e He e e He ke He He Ke GLOBUS_URL is a class that acts as a wrapper to the globus url t globus url t is taken as a parameter to globus gass copy register handle to url GLOBUS URL is taken as a parameter to
51. RRR ERR KK ERK ERK KKK EKER ERR KK ERK KERR KER ARR RK ERE ERK This function is used to check the validity of the local credentials probably generated by the grid proxy init bool getCredential gss_cred_id_t credential_handle OM_uint32 major_status OM_uint32 minor_status major_status globus_gss_assist_acquire_cred amp minor_status GSS_C_INITIATE or GSS_C_ACCEPT credential handle if major status GSS S COMPLETE return false else return true f BREE RRR ARA AAA AA AAA AAA AAA AA AA AAA ARA ARA RA KKK KEK ERK KK RK KERR KERR KERR KR ER ERK 176 Enabling Applications for Grid Computing with Globus Main program create a listen socket receive the message and close the socket _ macro is used to check the error code of each Globus function and display the Globus Error message HL kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk main First thing to do activate the module globus module activate GLOBUS IO MODULE globus result t t globus io attr t io attr globus io tcpattr init amp io attr gss cred id t credential handle GSS C NO CREDENTIAL Authenticate with the GSSAPI library if getCredential amp credential_handle cerr lt lt you are not authenticated exit 1 i globus io secure authorization data t auth data globus io secure authorization data initialize amp auth data globus io attr set secure authentication mo
52. RRR RR RRR RRR ERR KK RR KK KR KKK KKK ARA AA RARA AAA A ERK AIA AAA This is a basic implementation of a broker It checks all available Linux nodes and teir CPU usage Use GetLinuxNodes The first parameter is a vector of strings that will contain the list of ost in returns The second parameter is the number of nodes requested The most interesting part are the ldap calls and the way to proceed to retrieve information from the MDS server using OpenLdap C API other interesting implementation can couple LDAP information with other info in a DB for example that Time zone of the execution host location service level aggrement with the requester and the resources provider f BRRRR RRR ARA AAA AA AAA AAA AAA KK RRR KERR KR KEK KERR EKER ERR K KER KK RRR e ke ERE A namespace itso_broker class Host string hostname longcpu public Host string h int c hostname h cpu c Host string getHostname return hostname int getCpu return cpu F bool predica Host a Host b return a gt getCpu gt b gt getCpu void GetLinuxNodes vector lt string gt amp res int n LDAP ldap_server LDAPMessage reply 328 Enabling Applications for Grid Computing with Globus LDAPMessage entry char attrs 1 char server GRID INFO HOST int port 7 atoi GRID INFO PORT char base dn GRID INFO BASEDN list of attributes that we want inclu
53. Single job gt different multiple jobs Sub jobs No subjobs gt deeply staged subjobs Batch simple parallel application jobs EJBs based jobs complex jobs Independent gt strongly depending Small gt large Standard DLLs specific DLLs standard settings gt special settings Appendix A Grid qualification scheme 299 Qualification criteria Weight factors H M L Com ment Range Effort Skills show low to high stoppers efforts special care base values Runtime None required gt environ standard runtime ment gt special runtime required None required gt simple beans JSP gt EJB gt specific needs Foreign None required gt applica standard tion applications gt special settings installa tion Hardware None gt depend standard IT ent devices gt special IT devices gt special other devices Redund Not required gt ant job heavily execution depending on Scaveng All jobs ing grid individualized for scavenging gt not suitable for scavenging 300 Enabling Applications for Grid Computing with Globus Qualification criteria Weight factors H M L Com ment Range Effort Skills show low to high stoppers efforts special care base values Job data Command line y o parameter gt message queue gt data file gt database gt APIs RO files gt RO DBMS gt RW files g
54. There are at least two issues to consider here One is the scheduling of data transfers so that the data is at the appropriate location at the time that it is needed For instance if a data transfer is going to take one hour and the data is required by a job that must run at 2 00AM then schedule the data transfer in advance so that it is available by the time the job requires it You should also be aware of the number and size of any concurrent file transfers to or from any one resource at the same time 28 Enabling Applications for Grid Computing with Globus gt Data replica selection If you are using the Globus Data Replication service you will want to add the logic to your application to handle selecting the appropriate replica that is one that will contain the data that you need while also providing the performance requirements that you have 2 1 5 Scheduler The Globus Toolkit does not provide a job scheduler or meta scheduler However there are a number of job schedulers available that already are or can be integrated with Globus For instance the Condor G product utilizes the Globus Toolkit and provides a scheduler designed for a grid environment Scheduling jobs and load balancing are important functions in the Grid Most grid systems include some sort of job scheduling software This software locates a machine on which to run a grid job that has been submitted by a user In the simplest cases it may just blindly assign j
55. Web services CORBA and so on The facilities provided by Globus can be used to build grids and grid enabled applications today Many such environments have been built However when building such an infrastructure that is suitable for use in business environments there are other considerations that have not been fully addressed by the Globus Toolkit V2 2 For instance services such as life cycle management accounting and charge back systems and other facilities may be desired or required Another consideration when building a grid environment today is the ability to interconnect with other grids in the future To enable the interconnection between grids developed by different organizations that may be using different technologies requires standards to be put in place and adopted 1 2 2 OGSA and Globus Toolkit V3 The Open Grid Services Architecture OGSA is an evolving standard for which there is much industry support Globus Toolkit Version 3 will be the reference implementation for OGSA OGSA addresses both issues we discussed in the previous section First it changes the programming model to one that supports the concept of the various Chapter 1 Introduction 5 facilities becoming available as Web services This will provide multiple benefits including Acommon and open standards based set of ways to access various grid services using standards such as SOAP XML and so on The ability to add and integrate additional serv
56. a grid application 232 8 2 1 Add methods to execute the Globus commands 232 Enabling Applications for Grid Computing with Globus 8 2 2 Putting it together 236 8 3 SUMMA iaia avs RATE Rue Eig eR A INR M EN gt 244 Chapter 9 Application examples 202000005 245 9 1 Lottery simulation program sle ee 246 9 1 1 Simulate a lottery using gsissh in a shell script 246 9 1 2 Simulate a lottery using Globus commands 254 9 2 Small Blue example 262 9 2 GridifiCation c te RR danni Re eh 265 9 2 2 Implementation 0 000 ee eee 268 9 2 3 Compilation 275 9 24 EXecutiom Akai eh eh ed he bee Beto ele pneu 276 9 3 Hello World example 278 9 3 1 The Hello World application o 280 9 3 2 Dynamic libraries dependencies elles 281 9 3 3 Starting the application by the resource provider 285 9 3 4 Compilation safari dora LO 286 9 3 5 EXECUTION i ceo EROE ALE ER e ea 287 9 4 Sumrmary s desea ge Maho Debbie epefu uer Meet bh daa wae Pare have 288 Chapter 10 Globus Toolkit V3 0 es 289 10 1 Overview of changes from GT2 to GT3 2 20000 2 eee 290 10 1 1 SOAP message security eee 290 10 1 2 Creating grid Services 290 10 1 3 Security proxies Li 291 10 1 4 SOAP GSI plugin for C C Web services 291 10 2 OGSI implementation 291 10 3 Open Grid Serv
57. a large amount of data or a subset of a very large data set then moving the data set to the execution node is not always feasible Some of the considerations as to what is feasible include the volume of the data to be handled the bandwidth of the network and logical interdependences on the data between multiple jobs Data volume issues In order to use a grid application transparent access to its input and output data is required In most cases the relevant data is permanently located on remote locations and the jobs are likely to process local copies This access to the data means a network cost and it must be carefully quantified Data volume and network bandwidth play an important role in determining the scalability of a grid application Data splitting and separation As indicated in 4 1 8 Data topology on page 77 the data topology considerations may require the splitting extraction or replication of data from involved data sources in order to allow the grid to properly function and perform There are two general cases that are suitable for higher scalability in a grid application Independent tasks per job and a static input file for all jobs Independent tasks A suitable case for a grid enabled application is when the application can be split into several jobs that are able to work independently on a disjunct subset of the input data Each job produces its own output data and the gathering of all of the results of the jobs pr
58. and Example 7 13 on page 176 Chapter 7 Using Globus Toolkit for data management 169 An Internet socket is described as a globus_io_handle_t structure in the globus_io API This handle is created when calling the followings Globus functions gt globus io tcp create listener gt globus io tcp accept globus io tcp register accept gt globus io tcp connect These functions are respectively equivalent to the listen accept and connect POSIX system calls globus io tcp register accept is the asynchronous version of globus io tcp accept The Globus API adds authorization authentication and encryption features to the normal POSIX sockets via GSI and OpenSSL libraries A handle of type globus io secure authorization data t is used to manipulate these additional security attributes It needs to be initialized via globus io secure authorization data initialize before being used in other functions gt globus io attr set secure authentication mode is used to determine whether to call the GSSAPI security context establishment functions once a Socket connection is established A credential handle is provided to the function and needs to be initialized before it is used See the getCredential function in Example 7 12 on page 173 Example 7 6 Activating GSSAPI security on a socket communication globus io attr set secure authentication mode amp io attr globus io handle t GLOBUS IO SECURE AUTHENTICAT
59. any desired attributes in this case we are using parallel streams KAR KR KKK KKK KERR K KEK KK EKER KK KER KKK ERR EERE KEKE KKK KER EKER KEKE ERK KERR parallelism mode GLOBUS_FTP_CONTROL_PARALLELISM_FIXED parallelism fixed size PARALLELISM layout mode GLOBUS FTP CONTROL STRIPING BLOCKED ROUND ROBIN layout round robin block size 64 1024 globus ftp client operationattr set mode amp attr GLOBUS FTP CONTROL MODE EXTENDED BLOCK lobus ftp client operationattr set parallelism amp attr amp parallelism e lobus ftp client operationattr set layout amp attr amp layout e globus ftp client handle init amp handle amp handle attr BRR EK k k e RRR EKER ERE RK KERR KR ERK KERR KEKE KKK ERR KERR KERR KEK RR KERR EERE globus_ftp_client_put starts the protocol exchange on the control channel Note that this does NOT start moving data over the data channel RRR KR KKK RR KK ERK ERK KK ERK KEKE KEK KKK RK ERR EERE KEKE KEKE KER KEKE e e eke e keke ke done GLOBUS_FALSE result globus_ftp_client_put amp handle dst amp attr GLOBUS_NULL done_cb 0 if result GLOBUS SUCCESS globus_object_t err err globus_error_get result fprintf stderr 5s globus object printable to string err done GLOBUS TRUE else int rc FREAK AAAAARA AAA AA AAA AIAR RE EERE KEKE KEKE RRR KE RK KERR KER KERR ERK This is where the data movement over the data channel is init
60. are a few things to consider The GSI authentication mechanisms cannot be used if a program needs to connect to a database The Globus Toolkit 2 x does not provide an API to manipulate databases gt By default there is no information on databases that can be retrieved from the MDS Nevertheless you can create your own information provider See http www unix mcs anl gov slang mds iprovider example The Database Access and Integration Services Working group DAIS WG http www gridforum org 6 DATA dais htm is currently working on an implementation for such a database service for the Globus Toolkit V3 Several projects are currently working on related issues 4 2 3 Replication distribution of files across a set of nodes 86 Data replication is an optimization technique well known in the distributed systems and database communities as a means of achieving better access times to data Data replication is an optimization technique The key concepts are Aregistration operation that adds information about files on a physical storage system to an existing location and logical collection entries Hence new files can be made available to users by registering them in existing locations and collection entries lists of files Enabling Applications for Grid Computing with Globus gt The replication operation copies a file to storage systems that are registered as locations of the same logical collection and updates the de
61. as part of the job requesting process It provides the interfaces that control the allocation of each local resource lt may in turn utilize other services such as job schedulers The default implementation performs the following functions and forks a new process to launch the job Parses the RSL string passed by the client Allocates job requests to local resource managers Sends callbacks to clients if necessary Receives status requests and cancel requests from clients Sends output results to clients using GASS if requested YYYY Y Dynamically Updated Request Online Coallocator DUROC The Dynamically Updated Request Online Coallocator DUROC API allows users to submit multiple jobs to multiple GRAMs with one command DUROC uses a coallocator to execute and manage these jobs over several resource managers To utilize the DUROC API you can use RSL described above the API within a C program or the globus duroc command The RSL script that contains the DUROC syntax is parsed at the GRAM client and allocated to different job managers Chapter 2 Grid infrastructure considerations 21 Application enablement considerations Resource Mgmt There are several considerations for application architecture design and deployment related to resource management In its simplest form GRAM is used by issuing a globusrun command to launch a job on a specific system However in conjunction with MDS usually through a broker function the appli
62. broker and or scheduler may be used to launch each job at the best time and place within the grid Data producer and consumer Jobs that produce output data are called producers and jobs receiving input data are called consumers Instead of an active job as the final consumer of data there can be a defined data sink of any kind within the grid application This could be a database record a data file or a message queue that consumes the data 46 Enabling Applications for Grid Computing with Globus EN Figure 83 1 Parallel application flow For a given problem or application it would be necessary to break it down into independent units To take advantage of parallel execution in a grid it is important to analyze tasks within an application to determine whether they can be broken down into individual and atomic units of work that can be run as individual jobs This parallel application flow type is well suited for deployment on a grid Significantly this type of flow can occur when there are separate data sets per job and none of the jobs need results from another job as input For example in the case of a simulation application that is based on a large array of parameter sets against which a specific algorithm is to be executed a grid can help to deliver results more quickly A larger coverage of the data sphere is reached when the jobs can run in parallel on as many suitable nodes as possible Such a job can be as com
63. can be solved but have to be addressed up front in order to create a reasonable grid application An application with a serial job flow can be submitted to a grid but the benefits of grid computing may not be realized and the application may be adversely affected due to grid management overhead However by exploiting the grid and submitting the application to more powerful remote nodes it may very well provide business value In this list of knock out criteria the most critical items are named that most certainly hinder or exclude an application from use on a grid 1 High inter process communication between jobs without high speed switch connection for example MPI in general multi threaded applications need to be checked for their need of inter process communication 2 Strict job scheduling requirements depending on data provisioning by uncontrolled data producers 68 Enabling Applications for Grid Computing with Globus 3 Unresolved obstacles to establish sufficient bandwidth on the network 4 Strongly limiting system environment dependencies for the jobs see 3 5 Job dependencies on system environment on page 54 5 Requirements for safe business transactions commit and roll back via a grid At the moment there are standards for secure transaction processing on grids 6 High inter dependencies between the jobs which expose complex job flow management to the grid server and cause high rates of inter process com
64. cancel the job now Y N Y Job canceled NOTE You still need to clean files associated with the job by running globus job clean lt jobID gt globus m0 globus globus job clean https al itso apache com 47573 22041 1047929562 WARNING Cleaning a job means Kill the job if it still running and Remove the cached output on the remote resource 112 Enabling Applications for Grid Computing with Globus Are you sure you want to cleanup the job now Y N Y Cleanup successful 5 2 2 globusrun All jobs in the Globus Toolkit 2 2 are submitted by using the RSL language The RSL language is described in 2 1 2 Resource management on page 17 globusrun permits you to execute an RSL script The s options starts up a GASS server that can be referenced in the RSL string with the GLOBUSRUN GASS URL environment variable This local GASS server allows the data movement between the compute nodes and the submission node where the globusrun command is issued The syntax for the globusrun command is globusrun s r hostname f RSL script file globusrun s r hostname RSL script There is also a b option for batch mode that makes the command return a job contact URL that can be used with gt globusrun status job contact to check the status of a job gt globusrun kill job contact to kill a job Example 5 7 globusrun example globus m0 globus echo echo Hello 1 from HOSTNAME gt MyProg
65. chmod x MyProg globus m0 globus globusrun s r al amp executable GLOBUSRUN GASS URL PWD MyProg arguments Wor1d Hello World from al itso apache com globus job run and globus job submit actually generate and execute RSL scripts By using the dumprsl option you can see the RSL that is generated and used Example 5 8 globus job submit dumprsl example globus m0 globus globus job submit dumprs al bin sleep 60 amp executable bin sleep arguments 60 stdout x gass cache GLOBUS_GRAM_JOB_CONTACT stdout anExtraTag stderr x gass cache GLOBUS_GRAM_JOB_CONTACT stderr anExtraTag Chapter 5 Getting started with development in C C 113 5 2 3 GSlssh GSI OpenSSH is a modified version of the OpenSSH client and server that adds support for GSI authentication GSIssh can be used to remotely create a shell on a remote system to run shell scripts or to interactively issue shellcommands and it also permits the transfer of files between systems without being prompted for a password and a user ID Nevertheless a valid proxy must be created by using the grid proxy init command The problem of unknown sshd host keys is handled as part of the GSIssh protocol by hashing the sshd host key signing the result with the GSI host certificate on the sshd host and sending this to the client With this information the client now has the means to verify that a host key belongs to the host it is connecting to and detect
66. complexity while implementing transactions The future development of the OGSA standard may include transaction handling as a service though at the moment there is no support 3 10 Data criteria Any application at its core is processing data This means that we must take a closer look at data being used for and within a grid application A detailed discussion is provided in Chapter 4 Data management considerations on page 71 Data influences many aspects of application design and deployment and determines whether a planned grid application can provide the expected benefits over any other data solution 58 Enabling Applications for Grid Computing with Globus 3 11 Usability criteria While much of a grid computing solution is involved with infrastructure and middle ware it is still appropriate to consider aspects of the solution that relate to usability 3 11 1 Traditional usability requirements Traditional usability requirements address features that facilitate ease of use with the system These features address interaction display and affective attributes that provide users with an effective responsive and satisfactory means to use the system Hence these features must be also be addressed when developing a grid computing solution in other words this is business as usual and continues to play an important part in establishing the requirements for a grid solution Usability requirements are used to gt Provide b
67. copy url mode t getMode char getScheme char getURL bs class ITSO_GASS_TRANSFER_EXCEPTION class ITSO GASS TRANSFER public ITSO CB globus gass copy handle t gass copy handle globus gass copy handleattr t gass copy handleattr lobus gass transfer requestattr t dest gass attr lobus gass copy attr t dest gass copy attr lobus gass transfer requestattr t source gass attr obus gass copy attr t source gass copy attr lobus gass copy url mode t source url mode obus gass copy url mode t dest url mode obus ftp client operationattr t dest ftp attr lobus ftp client operationattr t source ftp attr void setSource GLOBUS URL amp void setDestination GLOBUS URL amp public ITSO_GASS_TRANSFER ITSO_GASS_TRANSFER void Transfer GLOBUS_FILE amp GLOBUS URL amp void Transfer GLOBUS_URL amp GLOBUS_FILE amp void Transfer GLOBUS_URL amp GLOBUS URL amp Q Q OQ aO a dca da 1 1 4 Q h endif itso_gass_copy C EEEF K H e keke ERK KERR ER EKER KK ERK KKK KEE RAR ERK EKER For a more complete example see globus url copy c RRR RK KKK KEK KHER KKK KKK KEKE RE RK KEKE KEKE KERKKER include itso_gass_copy h GLOBUS FILE GLOBUS FILE GLOBUS FILE GLOBUS FILE char filename Appendix B C C source code for examples 307 io handle globus_io_handle_t globus libc malloc sizeof globus io handle t file fd open filename 0 RDONLY convert file into
68. described in an RSL string that includes information such as the executable file its parameters information about redirection of stdin stdout and stderr and so on Basically it provides a standard way of specifying all of the information required to execute a job independent of the target environment It is then the responsibility of the job manager on the target system to parse the information and launch the job in the appropriate way The syntax of RSL is very straightforward Each statement is enclosed within parenthesis Comments are designated with parenthesis and asterisks for example this is a comment Supported attributes include the following gt rsl_substitution Defines variables gt executable The script or command to be run 18 Enabling Applications for Grid Computing with Globus gt arguments Information or flags to be passed to the executable gt stdin Specifies the remote URL and local file used for the executable gt stdout Specifies the remote file to place standard output from the job gt stderr Specifies the remote file to place standard error from the job queue Specifies the queue to submit the job requires a scheduler gt count Specifies the number of executions gt directory Specifies the directory to run the job gt project Specifies a project account for the job requires a scheduler gt dryRun Verifies the RSL string but does not run the job gt maxMemory Specifies the max
69. difference 10 1 1 SOAP message security Grid services must be built on a Grid Security Infrastructure GSI Globus Toolkit V2 used the Secure Socket Layer SSL protocol for its authentication and message protection The Globus Toolkit 3 implements a version of the Web Services SecureConversation protocol This allows for GSl s SSL based authentication to take place over standard Web Services SOAP messages which in turn allows for the use of the W3C Web Services Security specifications for message protection XML Encryption and XML Signature 10 1 2 Creating grid services One of the main advantages GT3 provides over GT2 is the ability to develop Web services for your grid application Grid services can be written in C Java Python and so on However the client to the grid service must be written in a language that provides bindings to WDSL GT3 provides Java APIs for programming OGSA services More information on creating grid services and clients in Java can be found at http www unix globus org ogsa docs alpha3 java programmers guide html C can be used to write clients to grid services However there is currently not an adequate WDSL to C compiler More information on OGSA client side C implementations can be found at http www unix globus org ogsa docs alpha2 c users guide html 290 Enabling Applications for Grid Computing with Globus 10 1 3 Security proxies The new implementation of the GSI libraries GSI 3 will acc
70. different data stores you may want to consider the use of federated databases They offer a single interface to the application and are capable of accessing data in large heterogeneous environments Federated databases have been developed in regards to data intensive tasks in the life sciences industry for drug discovery genome search and so on In these cases the federated databases are the central core of a data grid installation Federated database systems own the knowledge about location node database table record for instance and access methods SQL VSAM or others perhaps privately defined methods of connected data sources Therefore a simplified interface to the user a grid job or other client requires that the essential information for a request should not include the data source but rather use a discovery service to determine the relevant data source and access method 74 Enabling Applications for Grid Computing with Globus Federated DBMS Architecture Pluggable wrappered i Grid provider Grid provider datasources A SOAP l Firewall 1 Firewall 2 y over HTTPS D 8 i i aa m LJ Public Network 7 OGSA i Grid Client ga A Oracle Client Prog ervices Web Service i Oracle Fortal Documentum i Web Services m T
71. end else tcp lt lt Hello World cout lt lt exiting now lt lt endl tcp close h h HelloClient C finclude lt cc socket h gt finclude string using namespace std using namespace ost g g I usr include cc 2 L usr lib o S Ser2 C 1ccgnu2 lpthread 1d1 class GridApp public TCPStream char line 200 public GridApp InetHostAddress amp ia TCPStream ia 4097 char readline tcp gt getline line 200 return line 1 int main int argc char argv InetHostAddress FrontEndServerAddress AppServerAddress FrontEndServerAddress argv 1 TCPStream str FrontEndServerAddress 4096 Appendix B C C source code for examples 347 string hostname ticket str gt gt ticket str gt gt ticket str gt gt ticket str gt gt ticket str gt gt ticket cout lt lt Ticket lt lt ticket lt lt endl str gt gt hostname str gt gt hostname str gt gt hostname cout lt lt Hostname lt lt hostname lt lt end AppServerAddress hostname c_str GridApp App AppServerAddress App lt lt ticket lt lt endl cout lt lt App readline h Makefile globus makefile header flavor gcc32 globus io globus gass copy globus gss assist globus ftp client globus ftp control globus gram job globus common globus gram client globus gass server ez globus header include globus header all HelloServer HelloCl
72. files via different protocols The goals in doing this are to Provide a robust way to describe and apply file transfer properties for a variety of protocols HTTP FTP and GSIFTP Provide a service to support non blocking file transfer and handle asynchronous file and network events Provide a simple and portable way to implement file transfers The example in TSO GASS TRANSFER on page 306 provides a complete implementation of a C class able to transfer files between two storage locations that could transparently be A local file a GASS server a GridFTP server Note The complete documentation for this API is available at http www unix globus org api c globus 2 2 globus gass copy html index html 178 Enabling Applications for Grid Computing with Globus The Globus Toolkit 2 2 uses a handle of type globus gass copy handle tto manage GASS copy This handle is jointly used with three other specific handles that help to define the characteristics of the GASS operation Ahandle of type globus gass copy attr t used for each remote location involved in the transfer via gsiftp or http s protocol Ahandle of type globus gass copy handleattr t used for the globus gass copy handle tinitialization gt A handle of type globus gass transfer requestattr t request handle used by the gass transfer API to associate operations with a single file transfer request It is used in the globus gass copy attr s
73. globus url copy is the shell tool to use to transfer files from one location to another It takes two parameters that are the URLs for the specific file The prefix gsiftp lt hostname gt is used to specify a GridFTP server The following example copies a file from the host mO to the server a1 globus url copy gsiftp m0 tmp FILE gsiftp al tmp The following example uses a GASS server started on host bO and listening on port 23213 globus url copy https b0 23213 home globus OtherFile gsiftp al tmp The following example uses a local file as a source file globus url copy file tmp FILE gsiftp al tmp 7 5 Replication To utilize replication a replication server needs to be installed It consists of an LDAP server The Globus Toolkit 2 2 provides an LDAP server than can be used for this purpose See Installation on page 211 In the Globus Toolkit 2 2 the GSI security infrastructure is not used to modify entries in the LDAP repository Consequently a password and an LDAP administrator need to be defined for the replica server It will be used each time from the client side to perform write operations to the LDAP tree 208 Enabling Applications for Grid Computing with Globus 7 5 1 Shell commands The Globus Toolkit 2 2 provides a single shell command for manipulating replica catalog objects The format of the command is globus replica catalog HOST OBJECT ACTION Where HOST specifies the logical collection
74. gsiftp node i Smal1BlueSlave transfer push_back new ITSO_GLOBUS_FTP_CLIENT Smal1BlueSlave const_cast lt char gt dst c_str E Let s begin the transfer in parallel in asynchronous mode for i 0 i 8 i transfer i gt StartTransfer Let wait for the end of all of them for i 0 1 8 1 270 Enabling Applications for Grid Computing with Globus transfer i gt Wait globus module deactivate GLOBUS FTP CLIENT MODULE bs get the hostname using the globus shell function instead of POSIX system calls char hostname MAXHOSTNAMELEN globus_libc_gethostname hostname MAXHOSTNAMELEN used to store the RSL commands string rs req create all the jobs objects that will be used to submit the requests to the nodes We use a vector to store them vector ITSO GRAM JOB job for i 0 i 8 i job push back new ITSO GRAM JOB h By using gridftp SmallBlueSlave is copied onto the rmeote hosts as a plain file needs to chmod x to make it executable otherwise the job submission will fail cout lt lt chmod x on the remote hosts to make SmallBlueSlave executable lt lt endl for i 0 i 8 i rsl_req amp executable bin chmod count 1 arguments x SmallBlueSlave if job i Submit node i rs1 req exit 1 for i 0 i 8 i job i gt Wait finished stop everything StopGASSServer The game between the two players is run in an infinite
75. he has been writing IBM Redbooks and creating and teaching workshops around the world on a variety of topics He holds a Masters degree in Numerical Analysis from Syracuse University Copyright IBM Corp 2003 All rights reserved xiii Luis Ferreira also known as Luix is a Software Engineer at IBM Corporation International Technical Support Organization Austin Center working on Linux and grid computing projects He has 19 years of experience with UNIX like operating systems and holds a MSc Degree in SystemS Engineering from Universidade Federal do Rio de Janeiro in Brazil Before joining the ITSO Luis worked at Tivoli Systems as a Certified Tivoli Consultant at IBM Brasil as a Certified IT Specialist and at Cobra Computadores as a Kernel Developer and Software Designer Norbert Bieberstein is a Solution Development Manager at IBM Software Group in EMEA located in D sseldorf Germany working with system integrators and ISVs for about five years He has also worked as an IT architect at IBM s application architecture project office in Somers New York and before that as a consultant for CASE and software engineering at IBM s software development labs This work resulted in a book on CASE technology that was published in Germany in 1993 He has organized several educational events for IBMers business partners and customers on IBM SW products In 1997 he acted as the coordinating editor of the awarded IBM Systems Journal
76. initDestClient throws Exception dClient new GridFTPClient t2 itso tupi com 2811 dClient authenticate cred dClient setProtectionBufferSize 16384 dClient setType GridFTPSession TYPE_IMAGE dClient setMode GridFTPSession MODE EBLOCK dClient setDataChannelAuthentication DataChannelAuthentication SELF dClient setDataChannelProtection GridFTPSession PROTECTION SAFE Finally we will start the transfer defining the source and target files Example 6 21 GridFTP basic third party transfer 4 of 4 private void start throws Exception System out println Starting Transfer sClient transfer etc hosts dClient 150 Enabling Applications for Grid Computing with Globus tmp ftpcopy test false null System out print n Finished Transfer public static void main String args GridFTPthird ftp new GridFTPthird try ftp getCredentials ftp initDestClient ftp initSourceClient ftp start catch Exception e System out println Error e getMessage 6 6 2 GridFTP client server When transferring a file from a local client to a server or from a server to the client a local interface to the file storage must be supplied The toolkit provides two interfaces DataSink for receiving a file and ataSource for sending a file Example 6 22 GridFTP client server example 1 of 6 import org globus ftp DataChannelAuthentication import org globus ftp GridFTPClient import or
77. int i Series clear for i 8 i i find 8 different number between 1 and 60 do n GetARandomNumberBetweenlAnd60 while find Series begin Series end n Series end Series push front n h let display the result Series sort list long int iterator j for j Series begin j Series end j cout lt lt j lt lt cout lt lt end OutputFileMonitor seekp 1 ios beg OutputFileMonitor lt lt 100 InitialDrawNumber DrawNumber InitialDrawNumber while DrawNumber OutputFileMonitor seekp 1 ios beg OutputFileMonitor lt lt 100 OutputFileMonitor close SubmitGlobus script the script takes the tested draw as parameter fexample Submit 3 4 5 32 34 43 n 10000000 NodesNumber 8 temporary filename used by by GenerateDrawsGlobus to monitor the job we can also use the process id to increase the granularity TMP HOSTNAME i 0 the loop variable is used is all the for loops the format is 1234 n oop use here the broker developped for the redbook see chapter 8 mds executable Appendix B C C source code forexamples 353 for node in mds NodesNumber xargs do Nodes i node loop loop i i i 1 done echo The number of draws tested is n a sort the numbers in the specified draw 2 45 23 12 32 43 becomes 2 12 23 32 43 45 so that we could use grep to test this draw and the ouput of the draw
78. is itself passed as an argument so that the callback could invoke the method of this object via the this pointer It is associated as well as the callback function with globus gram client callback allow to manage its asynchronous behavior amp callback contact is the job contact URL that will be set after this call The setDone setFailed methods of the ITSO GRAM JOB object implemented in ITSO CB will permit the callback to modify the status of the job in the application Note that the status of the job in the application is independently managed from the status of the job that is be obtained via the following globus calls globus gram client job status blocking call globus gram client resgister job status non blocking call Here is an example of a callback to the globus gram client callback allow function Note that callbacks have a well defined prototype that depends on the Globus functions they are associated with The job contact URL is received as an argument as well as the ITSO GRAM JOB object pointer Example 5 12 globus gram client callback allow callback function static void callback func void user callback arg char job contact int state int errorcode The ITSO GRAM JOB object is retrieved in the callback via the first argument that allows to pass any kind of pointer to the callback This is the second argument of the globus gram client callback allow function ITSO GRAM JOB Monitor
79. is responsible for starting a new MJS instance It exposes only a single Service Data Element which is an array of Grid Services Handles of all active MJS instances The Managed Job Service MJS that is an OGSA service that can submit a job to a local scheduler monitor its status and send notifications The MJS starts two File Streaming Factory Services for stdout and the stderr of the job Their GSHs are stored in the MFS Service Data Element A Service Data Element SDE is an XML element containing information about a service that is identified by name and type which may contain any XML information and that may be queried or subscribed Chapter 10 Globus Toolkit V3 0 293 gt The File Stream Factory Service that is responsible for creating new instances of a File Stream Service The File Stream Service that is an OGSA service that given a destination URL will a stream from the local file the factory was created to stream stdout or stderr to the destination URL 1 Resource Master Managed Job Factory Service Client grid mapfile IE Local A gt Managed JFS host credentials user proxy GRIM gt credentials Figure 10 1 Globus Toolkit V3 job invocation The user then signs this request with her GSI proxy credentials and sends the signed request to the Master Managed Job Factory Service MMJFS on the resource that provides a function si
80. java io java util HttpServletRequest req request HttpServletResponse res response 236 Enabling Applications for Grid Computing with Globus String mdsHost al itso apache com String testApp home mOuser test sh JSPBean jspBean new JSPBean PrintWriter out String run String getresult String getstatus String logout String appselect see javax servlet http HttpServlet void javax servlet http HttpServletRequest javax servlet http HttpServletResponse public void doGet HttpServletRequest req HttpServletResponse resp throws ServletException IOException performTask req resp see javax servlet http HttpServlet void javax servlet http HttpServletRequest javax servlet http HttpServletResponse public void doPost HttpServletRequest req HttpServletResponse resp throws ServletException IOException performTask req resp public void performTask HttpServletRequest request HttpServletResponse response throws ServletException req request res response res setContentType text html res setHeader Pragma no cache res setHeader Cache control no cache try out res getWriter catch IOException e System err print n Job getWriter e Read and validate user input initialize try Which button selected run req getParameterValues run getresult req getParameterValues
81. locking mechanism and then the condition variable globus mutex init amp Monitor mutex globus mutexattr t NULL globus cond init amp Monitor cond globus condattr t NULL entering the monitor and clearing the flag Locking the Monitor to prevent anything else from changing the value of Monitor done globus mutex lock amp Monitor mutex Change the value of Monitor done to false initializing it Monitor done GLOBUS FALSE Releasing the lock on the monitor letting anything else access it globus mutex unlock amp Monitor mutex Setting up the communications port for returning the callback You pass it the callback function The callback contact is the callback identifier returned by the function globus gram client callback allow callback func void amp Monitor amp callback contact printf n tTEST submitting to resource manager Wn Send the GRAM request The rm contact specification and job state mask were retrieved earlier from the command line The callback contact was just returned by globus gram client callback allow The job request is returned by this function f rc globus gram client job request rm contact specification job state mask callback contact amp job contact if rc 0 if there is an error o printf TEST gram error d s n rc 360 Enabling Applications for Grid Computing with Glo
82. loop in which we repeatedly gt Serialize the current game Current ToDisk GAME gt Submit the calculation of the value for each column unlink eval remove the eval file for i 0 i 8 i cout lt lt submission on lt lt node i lt lt endl char tmpc 2 sprintf tmpc 5d i Chapter 9 Application examples 271 build the RSL commands rs req amp executable SmallBlueSlave arguments rsl_reqt tmpc 0 rsl req stdout https rs req hostname rs req 10000 rsl req get current dir name rs req eval stdin https rs req hostname rs req 10000 rsl req get current dir name rs req GAME count 1 submit it to the GRAM if Current CanPlay i if job i Submit node i rs req exit 1 bs And Wait for i 0 i 8 i if Current CanPlay i job i gt Wait gt Retrieve the results ifstream results eval while results eof results gt gt k gt gt s get the best one if s gt 1 1 s store its value toplay k remember the column to play i h results close Finally we exit the loop when one of the two players has won by using the HasWon method of the Current object if Current HasWon 1 BLACK Current Display break Example 9 11 SmallBlue Gridification SmallBlueMaster C while true Current Display do cout lt lt cin gt gt C c 1 0 272 Enab
83. n break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE FAILED printf tTEST Got GLOBUS GRAM PROTOCOL JOB STATE FAILED from job manager n globus mutex lock amp Monitor gt mutex Monitor gt done GLOBUS TRUE globus cond signal amp Monitor gt cond globus mutex unlock amp Monitor mutex 362 Enabling Applications for Grid Computing with Globus break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE DONE printf NtTEST Got GLOBUS GRAM PROTOCOL JOB STATE DONE from job manager n globus mutex lock amp Monitor gt mutex Monitor gt done GLOBUS TRUE globus cond signal amp Monitor gt cond globus mutex unlock amp Monitor mutex break Reports state change to the user Appendix B C C source code for examples 363 364 Enabling Applications for Grid Computing with Globus Additional material This redbook refers to additional material that can be downloaded from the Internet as described below Locating the Web material The Web material associated with this redbook is available in softcopy on the Internet from the IBM Redbooks Web server Point your Web browser to ftp www redbooks ibm com redbooks SG246936 Alternatively you can go to the IBM Redbooks Web site at ibm com redbooks Select the Additional materials and open the directory that corresponds with the redbook form number SG243936 Copyright
84. not play the most important role for the application but whose contents and tasks are of more importance may be written in other languages such as Java or in scripting languages such as Perl Within a single grid application one might even consider writing various parts in different languages depending on the requirements for the individual jobs and available resources Some of the key considerations include gt Portability to a variety of platforms This includes binary compatibility where languages such as Java provide an advantage as a single binary can be executed on any platform supporting the Chapter 3 Application architecture considerations 53 Java Virtual Machine Interpreted languages such as Perl also tend to be portable allowing the application to run no matter what the target platform Portability of source code can also be considered For instance one may decide to develop an application using C and then compile it multiple times for a variety of target platforms This will require additional work by the infrastructure to ensure that appropriate executables are distributed to any target resource Run time libraries modules Depending on the language and how the program is linked there may be a requirement for run time libraries or other modules to be available Again the successful running of an application will depend on these libraries being available on or moved to the target resource gt Interfaces to
85. o g g o GLOBUS CPPFLAGS GLOBUS LDFLAGS GLOBUS PKG LIBS Note Sometimes the package may be not be available in all flavors globus makefile header will only tell you that the package you required does not match the query but will not inform you that it exists in another flavor The application will be linked with Globus static libraries or Globus dynamic libraries depending on the kind of Globus installation you performed You can use the shell command 1dd under Linux to check if your application is dynamically linked to the Globus libraries located in GLOBUS_LOCATION ib Under Linux if your application uses dynamically linked Globus libraries then be sure that gt Either the LD LIBPATH PATH is properly set to GLOBUS_LOCATION lib when you run your application gt Or GLOBUS_LOCATION lib is present in etc Id so conf The list of main packages that are used in this publication are globus_common used for all cross platform C library wrappers globus_openldap for querying the MDS server globus_gass_server_ez to implement a simple GASS server globus_gass_transfer for GASS transfer globus_io for low level I O operation globus_gss_ for GSI security management globus ftp client globus ftp control for gsiftp transfer globus gram job for job submission vvvvvrvvy 108 Enabling Applications for Grid Computing with Globus 5 1 3 Globus module In Globus Toolkit V2 each Globus function belongs to an API prov
86. of utilization Client location And many others YYY Yy The broker finally proceeds to sort and set up the vector of strings that will be returned to the calling function This logic as well as the LDAP query can be easily customized to meet any specific requirements as shown in Example 5 22 Example 5 22 Broker algorithm implementation class Host string hostname long cpu public Host string h int c hostname h cpu c Host string getHostname return hostname int getCpu return cpu i bool predica Host a Host b return a gt getCpu gt b gt getCpu for each entry do values ldap get values ldap server entry attr 130 Enabling Applications for Grid Computing with Globus answer strdup values 0 ldap value free values if strcmp Mds Host hn attr 0 hostname answer if stremp Mds Cpu Free 15minX100 attr 0 cpu atoi answer if strcmp Mds Cpu Total count attr 0 cpu_nb atoi answer if stremp Mds Cpu speedMHz attr 0 speed atoi answer printf s s n attr answer check if we can really use this node if h globus gram client ping hostname c str nodes push back new Host hostname speed cpu nb cpu 100 sort nodes begin nodes end predica vector lt Host gt iterator i for i nodes begin n gt 0 amp amp i nodes end n i res push_back i gt getHostname cout lt
87. org globus ftp extended GridFTP protocol org globus ftp dc data channel functionality org globus ftp exception exceptions YYY Yy 6 6 1 GridFTP basic third party transfer Example 6 18 demonstrates how to perform a third party file transfer using extended block mode and GSI security using the GridFTP protocol In order to transfer a file from one server to another we need to create a client on each server In order to change any FTP client settings like Mode or Security the issuer must authenticate to the FTP client using its credentials Example 6 18 GridFTP basic third party transfer 1 of 4 import org apache log4j Level import org apache log4j Logger import org globus ftp DataChannelAuthentication import org globus ftp GridFTPClient import org globus ftp GridFTPSession import org globus gsi GlobusCredential import org globus gsi gssapi GlobusGSSCredential Imp1 import org ietf jgss GSSCredential GridFTPthird Performs a server to server GridFTP operation public class GridFTPthird private GridFTPClient sClient null source FTPClient private GridFTPClient dClient null destination FTPClient private GSSCredential cred null In Example 6 19 we will read the credentials from the proxy file For authentication we need a GSSCredential object so we have to change the GlobusCredential object to GSSCredential By doing that it is important to use the DEFAULT LIFETIME flag Exampl
88. performance grid resource This assumes that the job is started immediately and that it is not preempted by another job during execution The same batch job may be scheduled to run overnight when the resource demands are lower if a quick turnaround is not required The resource provider may charge different prices for these two types of service If the application has many independent sub jobs that can be scheduled for parallel execution the turnaround time could be improved appreciably by running each sub job on multiple grid hosts Turnaround time factors This section discusses some of the factors that can impact the turnaround time of applications run on the grid resources 36 Enabling Applications for Grid Computing with Globus Communication delays Network speed and network latency can have significant impact to the application performance if it requires communicating with another application running on a remote machine It is important to consider the proximity of the communicating applications to one another and the network speed and latency Data access delays The network bandwidth and speed will be the critical factors for applications that need to access remote data Proximity of the application to the data and the network capacity speed will be important considerations Lack of optimization of the application to the grid resource Optimum application performance is usually achieved by proper tuning and optimization on a pa
89. programs param echo a tr n sort n xargs Start the gass server on each nodes clean up the Monitoring file when leaving for i in 1oop do rsl amp executable GLOBUS LOCATION bin globus gass server arguments c t r environment LD LIBRARY PATH GLOBUS LOCATION lib file clean _up Monitor TMP globusrun o r Nodes i rs1 gt gass server i amp done file should be made executable fon all the execution nodes echo Jobs submission to the grid rs for i in loop do echo Nodes i rsl rs1 amp resourceManagerContact Nodes i rs1 rs1 executable GLOBUSRUN_GASS_URL PWD GenerateDrawsGlobus sh argum ents TMP n param subjobStartType 1oose barrier file_stage_in GLOBUSRUN_GASS_URL PWD GenerateDrawsGlobus GenerateDrawsGlobus TMP file clean up GenerateDrawsGlobus TMP environment LD_LIBRARY_PATH GLOBUS_LOCATION lib done echo rs1 globusrun s o rs1 amp for monitoring we copy locally the Monitor files created on each compute nodes This file content the percentage of tested draws Each files is suffixes by the nodes number statusnum is actually the sum of all the percentage Monitor files devided by 100 When it equals the number of nodes that means that we have finished echo Monitoring 354 Enabling Applications for Grid Computing with Globus rm f Monito
90. provide feedback to the user or to clean up or free up resources when required For instance if one job within an application fails other jobs that may be dependent on it may need to be cancelled before needlessly consuming resources that could be used by other jobs 2 1 3 Information services Information services is a vital component of the grid infrastructure It maintains knowledge about resource availability capacity and current utilization Within 22 Enabling Applications for Grid Computing with Globus any grid both CPU and data resources will fluctuate depending on their availability to process and share data As resources become free within the grid they can update their status within the grid information services The client broker and or grid resource manager uses this information to make informed decisions on resource assignments The information service is designed to provide gt Efficient delivery of state information from a single source Common discovery and enquiry mechanisms across all grid entities Information service providers are programs that provide information to the directory about the state of resources Examples of information that is gathered includes Static host information Operating system name and version processor vendor model version speed cache size number of processors total physical memory total virtual memory devices service type protocol port gt Dynamic host information
91. remote hosts to make SmallBlueSlave executable tl itso tupi com 34475 16083 1047519201 t2 itso tupi com 33326 6614 1047519203 t0 itso tupi com 58412 7839 1047519203 t3 itso tupi com 55107 29288 1047519236 t2 itso tupi com 33328 6615 1047519203 itso tupi com 34475 16083 1047519201 t0 itso tupi com 58414 7840 1047519203 tl itso tupi com 34478 16085 1047519201 t3 itso tupi com 55110 29289 1047519237 Contact on Contact on Contact on Contact on Contact on Job Job Job Job Job Job Job Finished Finished Finished Finished Finished Finished Finished on on on on on on on the server https the server https the server https the server https the server https Job Finished on https t1 Contact on the server https Contact on the server https Contact on the server https https t2 https t2 https t1 https t0 https t0 https t3 https t3 itso tupi itso tupi itso tupi itso tupi itso tupi itso tupi itso tupi COM COM COM COM COM COM COM Enabling Applications for Grid Computing with Globus 33328 6615 1047519203 33326 6614 1047519203 34478 16085 1047519201 58412 7839 1047519203 58414 7840 1047519203 55107 29288 1047519236 55110 29289 1047519237 12345678 submission on t0 submission on t1 submission on t2 submission on t3 submission on tO submission on t1 submission on t2 submission on t3 on the server https
92. script in tmp temp2 amp rsl substitution EXECDIR bin executable EXECDIR ps arguments ef directory tmp stdout tmp temp count 1 In Example 2 1 the globusrun command is used with MyTest rsl to execute MyTest sh on the resource system t3 The output of the script stored in tmp temp is then displayed using the Linux more command Example 2 1 Executing MyTest sh with MyTest rsl t3user t3 guser globusrun r t3 f MyTest rs globus gram client callback allow successful GRAM Job submission successful GLOBUS GRAM PROTOCOL JOB STATE ACTIVE GLOBUS GRAM PROTOCOL JOB STATE DONE t3user t3 guser more tmp temp total 116 drwxrwxrwt 9 root root 4096 Mar 12 15 45 drwxr xr x 22 root root 4096 Feb 26 20 44 drwxrwxrwt 2 root root 4096 Feb 26 20 45 ICE unix r r r 1 root root 11 Feb 26 20 45 X0 lock drwxrwxrwt 2 root root 4096 Feb 26 20 45 X11 unix drwxrwxrwt 2 xfs xfs 4096 Feb 26 20 45 font unix YW r r 1 t3user globus 0 Mar 10 11 57 17487 output t3user t3 guser In Example 2 2 MyTest2 rsl is used to display the currently executing processes using the ps command Example 2 2 Executing ps ef with MyTest 2 rsl t3user t3 guser globusrun r t3 f MyTest2 rs globus gram client callback allow successful GRAM Job submission successful GLOBUS GRAM PROTOCOL JOB STATE ACTIVE GLOBUS GRAM PROTOCOL JOB STATE DONE t3user t3 guser more tmp temp2 UID PID PPID C STIME TTY TIME CMD r
93. server cout col start endl 9 2 3 Compilation First generate the appropriate globus makefile header that will be later included in the Makefile Use globus makefile header and specify all the needed globus modules globus makefile header flavor gcc32 globus io globus gss assist globus ftp client globus ftp control globus gram job globus common globus gram client globus gass server ez globus header Compile with the following Makefile make f MakefileSmallBlue Example 9 13 MakefileSmallBlue globus makefile header flavor gcc32 globus io globus gss assist globus ftp client globus ftp control globus gram job globus common globus gram client globus gass server ez globus header include globus header all SmallBlueSlave SmallBlueMaster SmallBlue 55 0 C g c GLOBUS CPPFLAGS lt o Chapter 9 Application examples 275 SmallB Sma11B1 ue SmallBlue o GAME o g o 8 g g o g ueSlave SmallBlueSlave o GAME o SmallBlueMaster GAME o SmallBlueMaster o itso gram job o itso cb o itso gl obus ftp client o itso gass server o g g o GLOBUS CPPFLAGS GLOBUS LDFLAGS GLOBUS PKG LIBS 9 2 4 Execution 276 Issue grid proxy init to acquire a valid credential in the grid Start SmallBlueMaster and enter the column number you want to play globus m0 JYCode SmallBlueMaster we are listening on https m0 itso maya com 10000 chmod x on the
94. service that includes acceptable turnaround time Of course if building a grid and one or more applications that will be provided as a service on the grid then the service provider also has interest in maximizing the utilization and throughput of the systems within the grid The performance objectives of these two perspectives are discussed below Resource provider s perspective The performance objective for a grid infrastructure is to achieve maximum utilization of the various resources within the grid to achieve maximum throughput The resources may include but are not limited to CPU cycles memory disk space federated databases or application processing Workload balancing and preemptive scheduling may be used to achieve the performance objectives Applications may be allowed to take advantage of multiple resources by dividing the grid into smaller instances to have the work distributed throughout the grid The goal is to take advantage of the grid as a whole to improve the application performance The workload management can make sure that all resources within the grid are actively servicing jobs or requests within the grid Service requester s perspective The turnaround time of an application running on the grid could vary depending on the type of grid resource used and the resource provider s quality of service agreement For example a quick turnaround may be achieved by submitting a processing intensive standalone batch job to a high
95. single file system on shared SAN devices GFS is IBM certified on its xSeries servers only and for the Linux operating system GFS can support up to 256 nodes For more information see http www sistina com products gfs htm 4 2 13 Distributed approach Another approach to managing data needs in a grid is to distribute the data across the grid nodes through processes such as replication or mirroring The following sections describe these approaches in more detail Chapter 4 Data management considerations 95 Replica Catalog The Globus Toolkit Replica Catalog can keep track of multiple physical copies of a single logical file by maintaining a mapping from logical file names to physical locations A replica is defined as a managed copy of a file The catalog contains three types of objects The collections that are a group of logical names gt The locations that contain information required to map between logical name and the multiple locations of the associated replicas Each location represents a complete or partial copy of a logical collection on a storage system The location entry explicitly lists all files from the logical collection that are stored on the specified physical storage system gt The logical file entry that is an optional object to store attribute value pairs for each individual file They are used to characterize each individual file Logical files have globally unique names that may have one o
96. specific information It has the same functionality as the well known autoconf tools 106 Enabling Applications for Grid Computing with Globus The input parameters are gt The flavor you want for your binary gcc32 gcc32dbg for debugging purposes gcc32pthr for multi thread binary The flavor encapsulates compile time options for the modules you are building gt The list of modules that are used in your application and that need to be linked with your application are globus io globus gss assist globus ftp client globus ftp control globus gram job globus common globus gram client and globus gass server ez the static flag can be used to get a proper list of dependencies when using static linking Otherwise the dependencies are printed in their shared library form The output will be a list of pairs VARIABLE value that can be used in a Makefile as compiler and linker parameters For example GLOBUS CFLAGS D FILE OFFSET BITS 64 0 Wall GLOBUS INCLUDES I usr local globus include gcc32 GLOBUS LDFLAGS L usr local globus lib L usr local globus lib GLOBUS PKG LIBS lglobus gram client gcc32 lglobus gass server ez gcc32 lglobus ftp client gcc32 lglobus gram protocol gcc32 lobus gass transfer gcc32 lglobus ftp control gcc32 lglobus io gcc32 lobus gss assist gcc32 lglobus gssapi gsi gcc32 lobus gsi proxy core gcc32 lglobus gsi credential gcc32 lobus gsi callback gcc32 lglobus oldgaa gcc32 lglobus gsi
97. startTransfer method of the GASS TRANSFER class setURL allows to set up the URL as it is not set up in the constructor globus url parse is used to check the syntax of the url globus gass copy get url mode determine the transfer mode http https gsiftp of the url The type of this transfer mode is globus gass copy url mode t getMode returns this mode getScheme returns the scheme http https Chapter 7 Using Globus Toolkit for data management 181 getURL returns the string of the URL f BR RRRRRR RRR RR RK ER e ke ERR KERR KK RRR KR ERK ERK EKER KK EKER RK KR KK KER KR ERR EERE RK class GLOBUS URL globus url t url globus gass copy url mode t url mode char URL public GLOBUS URL GLOBUS URL free URL h bool setURL char destURL check if this is a valid URL if globus url parse destURL amp url GLOBUS SUCCESS cerr lt lt can not parse destURL lt lt destURL lt lt endl return false determine the transfer mode if globus gass copy get url mode destURL amp url mode GLOBUS SUCCESS cerr lt lt failed to determine mode for destURL lt lt destURL lt lt endl return false h URL strdup destURL return true ur globus gass copy url mode t getMode return url mode E char getScheme return url scheme char getURL return URL h f BRRR RRR RRR RR RK ER e ke ERR KK RRR KR KKK ERK ERK EKER KK EKER KK ER
98. sysconfig gcc32 lobus gsi cert utils gcc32 lglobus openss l error gcc32 obus openss l gcc32 lglobus proxy ssl gcc32 1ssl gcc32 lcrypto gcc32 lglobus common gcc32 GLOBUS CPPFLAGS I usr local globus include I usr local globus include gcc32 Q 1 1 1 1 1 Q a qa daa These variables are built based on the local installation of the Globus Toolkit 2 2 and provide an easy way to know where the Globus header files or the Globus libraries are located Consequently the procedure to compile a Globus application is the following 1 Generate an output file globus header in the example that will set up all the variables used later in the compile phase globus makefile header flavor gcc32 globus io globus gss assist globus ftp client globus ftp control globus gram job globus common globus gram client globus gass server ez globus openldap globus header 2 Add the following line in your Makefile to include this file include globus header 3 Compile by using make Chapter 5 Getting started with development in C C 107 Example 5 1 Globus Makefile example include globus_header all SmallBlueSlave SmallBlueMaster SmallBlue o o 0 C g c GLOBUS CPPFLAGS lt o e SmallBlue SmallBlue o GAME o g o 8 g SmallBlueSlave SmallBlueSlave o GAME o gcc o 8 g SmallBlueMaster GAME o SmallBlueMaster o itso gram job o itso cb o itso globus ftp client o itso gassserver o broker
99. t attr globus gass transfer listenerattr init amp attr scheme we want to listen on post 10000 globus_gass_transfer_listenerattr_set_port amp attr port Now we can start this gass server globus gass transfer requestattr t reqattr GLOBUS NULL purpose unknown globus mutex init amp mutex GLOBUS NULL globus cond init amp cond GLOBUS NULL done false int err globus gass server ez init amp GassServerListener amp attr scheme GLOBUS NULL purpose unknown server ez opts callback c function or GLOBUS NULL otherwise GLOBUS NULL or GLOBUS NULL otherwise if err GLOBUS SUCCESS cerr lt lt Error initializing GASS lt lt err lt lt lt lt endl exit 1 char gass server url globus gass transfer listener get base url GassServerlistener cout lt lt we are listening on lt lt gass server ur lt lt end B void StopGASSServer globus gass server ez shutdown GassServerListener globus module deactivate GLOBUS GASS SERVER EZ MODULE bs h 326 Enabling Applications for Grid Computing with Globus ITSO broker This is a simple implementation of a broker via the GetLinuxNodes function The function takes an integer as the number of required nodes and returns a vector of strings containing the host names The broker checks the status of the nodes by using the Globus ping function provided by the globus GRAM module API Consequently the
100. t2 itso tupi com 33335 6644 1047519211 on the server https tl itso tupi com 34489 16114 1047519209 on the server https t0 itso tupi com 58421 7869 1047519211 file in on https t2 itso tupi com 33335 6644 1047519211 file in on https tl itso tupi com 34489 16114 1047519209 file in on https t0 itso tupi com 58421 7869 1047519211 Contact Contact Contact Staging Staging Staging Contact Contact Contact Staging Staging Contact Staging Staging Contact Staging on the server https t2 itso tupi cor on the server https tl itso tupi cor on the server https t0 itso tupi cor 33339 6645 1047519211 34485 16113 1047519208 58424 7870 1047519211 file in on https tl itso tupi com 34485 16113 1047519208 file in on https t2 itso tupi com 33339 6645 1047519211 on the server https t3 itso tupi cor 55121 29325 1047519244 file in on https t0 itso tupi com 58424 7870 1047519211 file in on https t3 itso tupi com 55121 29325 1047519244 on the server https t3 itso tupi cor 55117 29324 1047519244 file in on https t3 itso tupi com 55117 29324 1047519244 Job Finished on https t2 itso tupi com 33335 6644 1047519211 Job Finished on https t1l itso tupi com 34485 16113 1047519208 Job Finished on https t2 itso tupi com 33339 6645 1047519211 Job Finished on https t0 itso tupi com 58424 7870 1047519211 Job Finished on https t1l itso tupi com 34489 16114 1047519209
101. the components of the Globus Toolkit Enabling Applications for Grid Computing with Globus Programming examples for Globus using Java In the previous chapter some examples of using the Globus Toolkit with C bindings were provided In this chapter we provide Java programming examples for most of the services provided by the Globus Toolkit Though the Globus Toolkit is shipped with bindings that can be used with C or C our examples here are based on Java We have done this for a few reasons First Java is a popular language that many of our readers may be able to read well enough to understand the concepts we are conveying Second future versions of the Globus Toolkit will likely ship with Java bindings and it is likely that more and more application development will utilize Java To use Java with the current Globus Toolkit V2 2 4 you can use the Java Commodity Kit JavaCoG More information on CoGs is available at http www unix globus org cog Specifically we recommend The Java CoG Kit User Manual available at http www globus org cog manual user pdf This manual describes the Java CoG toolkit in detail and describes its installation configuration and usage This chapter assumes that the reader is familiar with the referenced manual Copyright IBM Corp 2003 All rights reserved 133 6 1 CoGs Commodity Grid Kits is Globus way to integrate Globus tools into existing platforms CoG Kits allow users to p
102. the ITSO GRAM JOB class The SureJob C program is the implementation of such a job submission that checks the state of the job after the Wait method has returned by using the HasFailed method If failed the job is submitted to the next host provided by the broker HasFailed simply checks the value of a boolean attribute of an ITSO GRAM JOB object that becomes true when the job has failed This attribute is set to false by default but can be modified in the callback function of the globus gram client callback allow function by calling the setFailed method of the ITSO GRAM JOB object when a failure is detected The broker returns a vector of hostnames via the GetLinuxNodes call see Broker example on page 127 for more details It internally tests if the user is able to submit a job on the node with a globus ping before returning the vector of host names For various reasons the job may fail to execute on this node and SureJob C provides a simple way to overcome this failure Example 5 17 SureJob C include lt string gt include lt vector gt include lt broker h gt include globus_gram_client h include itso_gram_job h using namespace itso broker int main int argc char argv vector lt string gt Nodes GetLinuxNodes Nodes 3 Quickly check if we can run a job Chapter 5 Getting started with development in C C 123 globus module activate GLOBUS GRAM CLIENT MODULE ITSO GRAM JOB jo
103. the SetRequestDone method of the ITSO GRAM JOB object that actually calls the setDone method of the request cb ITSO CB object associated with the function globus gram client register job request The Submit method of the ITSO GRAM JOB class implements the job submission Example 5 15 GRAM job submission via an ITSO GRAM JOB object bool ITSO GRAM JO0B Submit string res string rsl failed false globus gram client callback allow itso gram job callback func void this amp callback contact int rc globus gram client register job request res c str rsl c_str GLOBUS GRAM PROTOCOL JOB STATE ALL callback contact GLOBUS GRAM CLIENT NO ATTR itso gram job request callback void this if rc 0 if there is an error printf TEST gram error d s n rc translate the error into english globus gram client error string rc return true else return false Chapter 5 Getting started with development in C C 121 Checking if we can submit a job on a node The function globus gram client ping can be used for diagnostic purposes to check whether a host is available to run the job Example 5 16 CheckHost C include globus gram client h include lt iostream gt int main int argc char argv globus_module_activate GLOBUS_GRAM_CLIENT_MODULE cout lt lt argv 1 if globus gram client ping argv 1 cout lt lt is okay lt lt endl else cou
104. the considerations and APIs we have discussed will not change with Globus Toolkit V3 there will be significant changes to the structure of the toolkit and the grid environment itself brought about by the new toolkit and OGSA Though many details are not yet available this chapter is intended to provide a short preview of what might be ahead in Globus Toolkit V3 Copyright IBM Corp 2003 All rights reserved 289 10 1 Overview of changes from GT2 to GT3 GT3 is based on OGSI to support the industry standardization of grid protocols It contains services and features available in GT2 but also allows users to create new services Some existing features that will be provided include GSI GRAM GridFTP and Information Services The major difference in the functionality between the two toolkits is that the interface to these features has become an OGSI service In Globus Toolkit V2 all services were independent of each other however in Globus Toolkit V3 all services can be accessed with common interfaces making it much simpler to develop applications that access these components Globus Toolkit V3 will also have a more consistent way to obtain information about services and the need for a GRIS is removed Each service in GT3 will act as its own GRIS The data returned from the service will be stored in XML format whereas in GT2 it is stored in LDIF format Modification to GT2 s MDS service is required to use it with GT3 because of the format
105. the grid infrastructure If the job must interface with the grid infrastructure such as the Globus Toolkit then the choice of language will depend on available bindings For example Globus Toolkit V2 2 includes bindings for C However through the CoG initiative there are also APIs and bindings for Java Perl and other languages Note that an application may not have to interface with the Globus Toolkit directly as it is more the responsibility of the infrastructure that is put in place That is given an appropriate infrastructure the application may be developed such that it is independent of the grid specific services One of the driving factors behind the OGSA initiative is to standardize on the way that various services and components of the grid infrastructure interface with one another This provides programming language transparency between two communicating programs That is a program written in C for example could communicate with or through a service that is written in another language 3 5 Job dependencies on system environment 54 As shown earlier a grid application does not require a homogenous runtime environment but there are certain considerations to be made in order to plan for the most beneficial deployment of it For any job in a grid application the following environmental factors may affect its operation When developing an application one must consider these factors and either design it to be as independent of
106. the grid services which can mean additional overhead The grid architecture has to balance the individual advantages under the framework given by the available infrastructure and business needs 3 3 Job criteria A grid application consists of a number of jobs which may often be executed in parallel In this section the special requirements for each of these jobs are discussed A job as part of a grid application can theoretically be of any type Batch standard application parallel application and or interactive 3 3 1 Batch job Jobs in a grid environment could be a traditional batch job on a mainframe or a program invoked via a command line interface in a Windows Unix or Linux environment Normally arguments are passed to the program which can represent the data to process and parameter settings related to the job s execution Depending on its size and the network capacities a batch job can be sent to the node along with its arguments and remotely launched for execution The job can be a script for execution in a defined environment for example REXX Java or Perl script or an executable program that has few or no special requirements for operating system versions special DLLs to be linked to JAR files to be in place or any other special environmental conditions The client portal and or broker may need to know the specific requirements for the job so that the appropriate resource can be allocated The data for its co
107. the transfer runs using all defaults which implies standard FTP stream mode Note that while this program shows proper usage of the Globus GridFTP client library functions it is not an example of proper coding style Much error checking has been left out and other simplifications made to keep the program simple HH K KKK KKK KKK KKK KKK RK ERR he Ske RK KEKE KEKE RK KKK KER KK ERR KE RK KER KARA AAA AA AAA F HF X include lt stdio h gt include globus_ftp_client h static globus_mutex_t lock static globus_cond_t cond static globus_bool_t done define MAX_BUFFER_SIZE 2048 define ERROR 1 define SUCCESS 0 BRR RRR RRR RK RR RK RR de ke ERR KK RK ERR KKK KR ERK KERR EKER ERK KARA AAA AAA AAA done_cb A pointer to this function is passed to the call to globus_ftp_client_put and all the other high level transfer 196 Enabling Applications for Grid Computing with Globus operations It is called when the transfer is completely finished i e both the data channel and control channel exchange Here it simply sets a global variable done to true so the main program will exit the while loop KKK KKK KKK KKK KERR KKK RK ERK KKK RK KEKE KEKE RRR KARA ARA A ARR AAA EERE KERR ERE static void done cb void User arg globus ftp client handle t handle globus object t err char tmpstr if err fprintf stderr s globus object printable to string err globus mutex lock amp l
108. this section we perform the transfer of the dynamic library to the application server We use the ITSO GLOBUS FTP CLIENT class to do the task Note that we use the local directory to perform the task In real case example a storage server would be used instead of a local directory globus url copy gsiftp storage server commoncpp2 1 0 8 tar gz gsiftp application server commoncpp2 1 0 8 tar gz f ERA RARA AAA RA AAA A RRR KR AAA AAA ERK AAA ARA AA AAA KERR KERR ERE REE GLOBUS_URL source destination source setURL gsiftp m0 tmp commoncpp2 1 0 8 tar gz string dst dst gsiftp node commoncpp2 1 0 8 tar gz destination setURL dst globus module activate GLOBUS GASS COPY MODULE ITSO GASS TRANSFER transfer transfer Transfer source destination globus module deactivate GLOBUS GASS COPY MODULE ERA R ARA AAA RA AAA KERR AIA RR KR ARA KERR KEKE ARA AAA AIAR AAA AAA In this section we submit the compilation of the dynamic libray The script Compile that must be in the current directory is transferred to the remote host and executed The result is the installation of the CommonC toolkit in the tmp directory of the user under which the script was executed globus in the lab environement of the redbook f ERBA K AA AA AAA AAA A AAA KERR KR ERK ERK KERR KEKE ARIA AAA EKER KEKE ERK A 284 Enabling Applications for Grid Computing with Globus used to store the RSL c
109. to remove the file from the cache GASS refers to the files in the cache with a tag equal to their URL The following command removes a single reference of tag itso from the specified URL If this is the only tag then the file corresponding to the URL on the local machine s cache will be removed globus gass cache delete t itso gsiftp t0 home globus gsiclient2 The following removes a reference to the tag itso from all URLs in the local cache globus gass cache cleanup tag t itso To remove all tags for the URL gsiftp t0 nome globus gsiclient2 and remove the cached copy of that file globus gass cache cleanup tag gsiftp t0 home globus gsiclient2 Note GRAM_JOB_CONTACT is the tag used for a job started from GRAM and that uses GASS All GRAM JOB CONTACT tags are deleted when the GRAM job manager completes 7 4 GridFTP The Globus Toolkit 2 2 uses an efficient and robust protocol for data movement This protocol should be used whenever large files are involved instead of the http and https protocols that can also be used with the GASS subsystem 194 Enabling Applications for Grid Computing with Globus The Globus Toolkit 2 2 provides a GridFTP server based on wu ftpd code and a C API that can be used by applications to use GridFTP functionality This GridFTP server does not implement all the features of the GridFTP protocol It works only as a non striped server even if it can inter operate with other striped servers AII
110. unlock amp mutex void ITSO CB Wait globus mutex lock amp mutex while IsDone globus cond wait amp cond amp mutex globus mutex unlock amp mutex h ITSO GRAM JOB This class provides methods to easily submit a job to a Globus grid It works in an asynchronous way The Submit method takes a host name and the RSL string to submit the job and returns immediately gt The Wait method waits for the completion of the job The class is derived from ITSO CB and provides the following methods to check the status of the job gt l sDone to check the status of the job finished or not gt HasFailed to check if the GRAM submission has failed Note that this method will not detect if the executable aborted during execution or if it hangs The class can be used several times to submit different jobs with either a different host name or a different RSL string Use the Continue method to be able to use the Submit method again itso gram job h ifndef ITSO GRAM JOB H define ITSO GRAM JOB H 316 Enabling Applications for Grid Computing with Globus include lt cstdio gt include lt string gt include globus gram client h include itso cb h class ITSO GRAM JOB public ITSO CB char job contact char callback contact This is the identifier for globus gram job request bool failed used to check if a job has failed public ITSO GRAM JOB ITSO GRAM JOB bool Subm
111. void ITSO GLOBUS FTP CLIENT Transfer globus byte t buffer globus size t amp length globus off t amp offset int rc rc fread buffer 1 MAX BUFFER SIZE fd if ferror fd SUCCESS 314 Enabling Applications for Grid Computing with Globus ITSO_CB printf Read error in function data cb errno return globus ftp client register write amp handle buffer rc offset length feof fd SUCCESS itso globus ftp client data cb void this Below is a sample callback mechanism itso cb h ifndef ITSO CB H define ITSO CB H finclude cstdio include lt iostream gt include lt globus_common h gt class ITSO CB globus mutex t mutex globus cond t cond globus bool t done public ITSO CB globus mutex init amp mutex GLOBUS NULL globus cond init amp cond GLOBUS NULL done GLOBUS FALSE js ITSO_CB globus mutex destroy amp mutex globus cond destroy S amp cond E globus_bool_t IsDone void setDone void Continue virtual void Wait h fendif itso cb C include itso cb h d n errno Appendix B C C source code for examples 315 globus bool t ITSO CB IsDone return done void ITSO CB setDone globus mutex lock amp mutex done GLOBUS TRUE globus cond signal amp cond globus mutex unlock amp mutex void ITSO CB Continue globus mutex lock amp mutex done GLOBUS FALSE globus mutex
112. 2 GriPhyri cic ELDER ORI Gee ni aoe ed e var a 102 4 3 3 Particle Physics Data Grid 103 4 4 Summaryc scele LE RR rc ee Ir e xvi dt 103 Chapter 5 Getting started with development in C C 105 5 1 Overview of programming environment 106 5 1 1 Globus libc APIs LL 106 5 1 2 Makefile iii RI a 106 5 1 3 Globus module e 109 5 1 4 Callbacks isses EVE dct a 109 5 2 Submitting a job 110 5 2 1 Shells commands 000 eee tee 111 5 2 2 QlODUSIUN iii ete aD Jeera aa aa ea i 113 SZI GSISSH rep ee Eu eee O re deb edd 114 5 2 4 Job submission skeleton for C C applications 117 532 5 SIMPLE DIOKE a teed ae ar iad ae E VES AGN hy RRA a 124 5 9 SUmlTialys x igo ts wie eee eo Eee MR ag e MC Ue ds 132 Chapter 6 Programming examples for Globus using Java 133 Contents V vi BF GOG Si cscs tye retata ital 134 6 2 3Sl PtOXV cubare hehe ESSI pae RUP ee ales 134 6 3 GRAM zi e ste eoe tog le ax sorta RU ue ton es Me spe eae Se 138 6 3 1 Gramo erei a a E N teens 138 6 3 2 GramJobListener llle 138 6 3 3 GramException erroa rru bobra ERDRE a RER a ERA 139 6 4 MDS sin e Ale A li RN li oi 140 6 4 1 Example of accessing MDS 0 0000 eee eee 141 C5 RO Leo ote ds a ELM en dii ma pie 145 6 5 1 Example using RSL atret arabit Erh 145 6 6 Grid ET Ps ehi orbi la e E HER ilaele 148 6 6 1 GridFTP basic third party transfer llle 149 6 6 2 GridFTP client se
113. 2775 GenerateDraws 100 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 52775 Jobs submission to the grid d2 al c2 cl tl t3 itso apache com a2 b2 t2 di itso apache com itso cherokee com itso cherokee com itso cherokee com itso tupi com itso tupi com itso apache com itso bororos com itso tupi com Monitoring d2 al ti b2 7 itso apache com Monitor 46 c2 cl itso tupi com Monitor 51 t3 dl a2 itso bororos com Monitor t2 itso dakota com Monitor 37 itso cherokee com Monitor itso cherokee com Monitor itso tupi com Monitor 43 itso dakota com Monitor 47 itso apache com Monitor 49 5 40 itso tupi com Monitor 55 14 10 15 20 34 47 57 GOT IT on al itso apache com d2 al c2 cl tl t3 itso dakota com Monitor 1 a2 b2 t2 di itso dakota com Monitor 97 5 itso apache com Monitor 100 itso cherokee com Monitor 100 itso cherokee com Monitor 100 itso tupi com Monitor 100 itso tupi com Monitor 99 o KA Oy 00 itso apache com Monitor 100 itso bororos com Monitor 84 itso tupi com Monitor 100 9 K se se Chapter 9 Application examples 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 253 9 1 2 Simulate a lottery using Globus commands We propose to implement the previous example by using Globus Toolkit 2 2 commands gt globusrun will be used to submit the job The type of the job will be a multi request query
114. 358 Enabling Applications for Grid Computing with Globus Main Code RAK KKK KKK KKK KKK KK KR KKK KER KK ERK KEK EKER KARA KARA e ke e int main int argc char argv int callback_fd int job_state_mask int rc The return value of the request function If successful it should be 0 char callback_contact This is the identifier for the callback returned by globus_gram_job_request char job_contact This is the identifier for the job returned by globus_gram_job_request ef char rm_contact char specification globus_bool_t done my_monitor_t Monitor Retrieve relevant parameters from the command line if argc 3 amp amp argc 4 amp amp argc 5 invalid parameters passed printf Usage s rm contact specification lt job_state_mask gt lt debug gt n argv 0 exit 1 if rc globus module activate GLOBUS GRAM CLIENT MODULE GLOBUS SUCCESS printf tERROR gram module activation failed n exit 1 rm contact char globus malloc strlen argv 1 1 strcpy rm contact argv 1 specification char globus_malloc strlen argv 2 1 strcpy specification argv 2 if argc 3 job state mask atoi argv 3 else Appendix B C C source code for examples 359 job state mask GLOBUS GRAM PROTOCOL JOB STATE ALL Initialize the monitor function to look for callbacks It initializes the
115. 63 Example 9 9 Standalone version int Simulate GAME newgame int col int 1 0 s int start newgame Value col WHITE newgame Play col WHITE 1 0 for int k 1 k XSIZE 1 k s newgame Value k BLACK if s gt 1 1 s E start 1 return start main f EEEE E E H k k H k k k kk AA AA AAA AAA Start K EK e e e He e e KK ERK K A e eK K ke Kk ke Kk GAME Current XSIZE YSIZE int s l k toplay char c 2 while true Current Display do cout lt lt cin gt gt C c 1 0 l atoi c while 1 lt 1 1 gt XSIZE Current CanPlay 1 Current Play 1 BLACK if Current HasWon 1 BLACK Current Display exit 1 A Simul ation RAK KKK KKK RAK KERR EERE KEKE ERE 1 100000 for k 1 k XSIZE 1 k if Current CanPlay k f EEEE E E k k H k k k kk k k ERE KERR KEK call Simulate EE Ke e ke e e ke e e e E He Ae eHe e KeK e ke e ke ee ke e s Simulate Current k if s gt 1 155 toplay k h ti h if 1 100000 cout NULL endl exit 1 264 Enabling Applications for Grid Computing with Globus Pi Current Play toplay WHITE if Current HasWon toplay WHITE Current Display exit 1 h h h The purpose of this example is to gridify the application by executing the Simulate function on a remote host Each evaluation of a tested column can be executed independently Each evaluation modifies the game data when simulating an attempt so ea
116. AM JOB HasFailed return failed StartGASSServer and StopGASSServer These two functions provide an easy way to start and stop a local GASS server The StartGASSServer takes one argument the port number on which the GASS server must listen on As the callback function used for globus gass server ez init does not take any argument an object cannot be passed to the callbacks Consequently if the application needs to start two local GASS servers two different callback functions must be used and globus gass server ez init must be called twice with a different callback each time itso gass server h ifndef ITSO GASS SERVER H define ITSO GASS SERVER H include lt unistd h gt include globus_common h include globus_gass_server_ez h include lt iostream gt namespace itso gass server void StartGASSServer int void StopGASSServer h fendif 324 Enabling Applications for Grid Computing with Globus itso_gass_server C include itso_gass_server h namespace itso_gass server globus_mutex_t mutex globus_cond_t cond boo done globus gass transfer listener t GassServerListener void callback c function globus mutex lock amp mutex done true globus cond signal amp cond void StartGASSServer int port 10000 Never forget to activate GLOBUS module globus module activate GLOBUS GASS SERVER EZ MODULE let s define options for our GASS ser
117. Computing with Globus globus ftp client handle destroy amp handle globus module deactivate all return 0 To compile the program gcc I usr local globus include gcc32 L usr local globus lib o gridftpclient2 gridftpclientl c lglobus ftp client gcc32 To use it globus m0 globus grid proxy init Your identity O Grid O Globus OU itso maya com CN globus Enter GRID pass phrase for this identity Creating DYOXY wesc new e ER e ER E p SI m p Des the E ER eee Done Your proxy is valid until Thu Mar 6 02 17 53 2003 globus m0 globus gridftpclientl LocalFile gsiftp g2 tmp RemoteFile Partial transfer All operations are asynchronous and require a callback function that will be called when the operation has been completed Mutex and condition variables must be used to ensure thread safety GridFTP supports partial transfer To do this you need to use offsets that will determine the beginning and the end of data that you want to transfer The type of the offset is globus off t The globus ftp client partial put and globus ftp client partial get are used to execute the partial transfer The Globus FTP Client library provides the ability to start a file transfer from a known location in the file This is accomplished by passing a restart marker to globus ftp client get and globus ftp client put The type of this restart marker is globus ftp client restart marker t and must be initialized by calling globu
118. D width 501 height 37 gt lt TABLE border 1 width 474 gt lt TBODY gt lt TR gt lt TD width 20 gt lt INPUT type submit name status value My Application Status gt lt TD gt lt TD width 20 gt lt INPUT type submit name result value My Application Results gt lt TD gt lt TD width 20 gt lt TD gt lt TD width 20 gt lt TD gt lt TD width 20 gt lt INPUT type submit name logout value Logout gt lt TD gt lt TR gt lt TBODY gt lt TABLE gt lt TD gt lt TR gt lt TR gt lt TD width 209 height 225 valign top gt lt P gt Select an application and click Grid Application Application button below lt P gt lt SELECT size 4 name appselect gt lt OPTION value weather gt WeatherSimulation lt OPTION gt lt OPTION value gene gt GeneProject lt OPTION gt lt OPTION value test gt TestApp lt OPTION gt lt OPTION value demo selected gt DemoApp lt OPTION gt Chapter 8 Developing a portal 223 lt SELECT gt lt br gt lt INPUT type submit name submit value Submit Grid Application gt lt BR gt lt TD gt lt TD width 501 height 225 gt lt P gt This grid portal is a demontration to show how easily you can submit an application to the grid for execution In this demo you will be able to lt P gt lt UL gt lt LI gt Submit your application to the grid lt LI gt lt LI gt Query your application status lt LI gt lt LI gt Query your results lt
119. Data xsize ysize E bool CanPlay int amp col if get1 col 0 return false return true E bool HasWon int col int player int line bool res false line available col linet res test 1 0 col line player res test 1 1 col line player res test 0 1 col line player res test 1 1 col line player return res h int Value int col int player int line if line available col 0 return 0 set col line player int res 0 res calculate 1 0 col line res calculate 1 1 col line res calculate 0 1 col line res calculate 1 1 col line set col line 0 return res B Makefile globus makefile header flavor gcc32 globus_io globus_gss_assist globus ftp client globus ftp control globus gram job globus common globus gram client globus gass server ez globus header 340 Enabling Applications for Grid Computing with Globus include globus_header all SmallBlueSlave SmallBlueMaster SmallBlue o 0 C g c GLOBUS CPPFLAGS lt o e SmallBlue SmallBlue o GAME o g o g SmallBlueSlave SmallBlueSlave o GAME o g o 8 g SmallBlueMaster GAME C SmallBlueMaster C itso gram jobs callback C itso cb C itso globus ftp client C itso gass server C broker C g g o GLOBUS CPPFLAGS GLOBUS LDFLAGS GLOBUS PKG LIBS lldap gcc32pthr HelloWorld example Below is a sample HelloWorld program HelloFrontEnd C define GNU SOURCE man
120. Enabling Applications for Grid Computing with Globus Enable your applications for grid computing Utilize the Globus Toolkit Programming hints tips and examples Bart Jacob Luis Ferreira Norbert Bieberstein Candice Gilzean Jean Yves Girard Roman Strachowski Seong Steve Yu ibm com redbooks Red D ooks International Technical Support Organization Enabling Applications for Grid Computing with Globus June 2003 SG24 6936 00 Note Before using this information and the product it supports read the information in Notices on page xi First Edition June 2003 This edition applies to Version 2 2 4 of the Globus Toolkit Copyright International Business Machines Corporation 2003 All rights reserved Note to U S Government Users Restricted Rights Use duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp Contents Figures D Eee iaia ix Notices sc etu E nit ent a ee aa xi Trademarks d Xie ia ii d ia ife I AI I ia i aa xii Preface ooo see eR i ei xiii The team that wrote this redbook LL xiii Become a published author xvi Comments Welcome xvi Chapter 1 Introduction 1 1 1 High level overview of grid computing LL 3 1 1 1 Types of grids cec eee RR EE eyes 3 1 2 Globus Project iii pi rD E ii EI pei 4 1 2 1 Globus Toolkit Version 2 2 5 1 2 2 OGSA and Globus Toolkit V3 LL 5 1 3 Grid components A high level perspective l l
121. I i Gateway i Federated Benes ere Client DBMS Firewall JDBC E Y I m ODBC IT SESTA possa etc Storage Tank Infrastructure Figure 4 1 Federated DBMS architecture The use of such a federated database solution can also be considered as part of a more general grid application where the jobs access data by acting as clients of a federated database Additionally as shown in Figure 4 1 the use of Storage Tank technology for large data store capacities can be included and managed by federated databases IBM data management products for grid applications There are several IBM products that support the federated database concept such as DB2 Federated Server DB2 Data Joiner DB2 Discovery Link DB2 Relation Connect DB2 Information Integration and many more Additionally there are several white papers products solution offerings and related material available from the IBM DB2 Web sites Please see the following Web site for more details and support http ww ibm com software data 4 1 3 Locking In a grid context locking is also important Read write locking is well understood as in any other concurrency situation with databases and other data sources Read only locks for keeping accuracy of data sets should be considered too Chapter 4 Data management considerations 75 4 1 4 Temporary data spaces Within grid applications temporary d
122. IBM Corp 2003 All rights reserved 365 Using the Web material The additional Web material that accompanies this redbook includes the following files File name Description README 6936 A sort desrciption of the following files 3936Samp zip A zip file including various source files from examples in this publication 3936Samp tar A tar file including the same contents as the above zip file How to use the Web material Create a subdirectory folder on your workstation and unzip or untar the contents of the Web material zip tar file into this folder 366 Enabling Applications for Grid Computing with Globus Related publications The publications listed in this section are considered particularly suitable for a more detailed discussion of the topics covered in this redbook IBM Redbooks For information on ordering these publications see How to get IBM Redbooks on page 372 Note that some of the documents referenced here may be available in softcopy only Introducing IBM Tivoli License Manager SG24 6888 Introduction to Grid Computing with Globus SG24 6895 Fundamentals of Grid Computing REDP3613 Other publications These publications are also relevant as further information sources The Java CoG Kit User Manaul Gregor von Laszewski Beulah Alunkal Kaitzar Amin Jarek Gawor Mihael Hategan Sandeep Nijsure Available at http www globus org cog manual user pdf Network Security Essential
123. INE BUFFER URLs that have character will be expanded to the home directory of the user who is running the server server ez opts GLOBUS GASS SERVER EZ TILDE EXPAND URLs that have user character will be expanded to the home directory of the user on the server machine server ez opts GLOBUS GASS SERVER EZ TILDE USER EXPAND get requests will be fullfilled server ez opts GLOBUS GASS SERVER EZ READ ENABLE put requests will be fullfilled server ez opts GLOBUS GASS SERVER EZ WRITE ENABLE for put requets on dev stdout will be redirected to the standard output stream of the gass server server ez opts GLOBUS GASS SERVER EZ STDOUT ENABLE for put requets on dev stderr will be redirected to the standard output stream of the gass server server ez opts GLOBUS GASS SERVER EZ STDERR ENABLE put requests to the URL https host dev globus gass client shutdown will cause the callback function to be called this allows the GASS client to communicate shutdown requests to the server server ez opts GLOBUS GASS SERVER EZ CLIENT SHUTDOWN ENABLE Chapter 7 Using Globus Toolkit for data management 189 Before starting the server with globus gass server ez init a listener must be created This is the opportunity to Define a port number on which the GASS server will listen gt Select the protocol as secure or unsecure Example 7 17 Protocol selection or scheme
124. ION MODE GSSAPI use GSI credential handle gt globus io attr set secure authorization mode is used to determine what security identities to authorize as the peer to security handshake that is done when making an authenticated connection The functions take both a globus io handle and a Globus secure attribute handle The mode is specified in the second argument GLOBUS IO SECURE AUTHORIZATION MODE SELF authorizes any connection with the same credentials as the local credentials used when creating this handle For the complete list of available authorization modes see http www unix globus org api c globus 2 2 globus io html group security html a7 Example 7 7 globus io attr set secure authorization mode globus io attr set secure authorization mode 170 Enabling Applications for Grid Computing with Globus amp io_attr globus_io handle t GLOBUS IO SECURE AUTHORIZATION MODE SELF amp auth data gt globus io attr set secure channel mode is used to determine if any data wrapping should be done on the socket connection GLOBUS IO SECURE CHANNEL MODE GSI WRAP indicates that data protection is provided with support for GSI features such as delegation Example 7 8 globus io attr set secure channel mode globus io attr set secure channel mode amp io attr globus io handle t GLOBUS IO SECURE CHANNEL MODE GSI WRAP gt globus io attr set secure protection mode is used to determine if any da
125. ITSO GRAM JOB user callback arg switch state case GLOBUS GRAM PROTOCOL JOB STATE STAGE IN cout Staging file in on job contact endl break case GLOBUS GRAM PROTOCOL JOB STATE STAGE OUT cout lt lt Staging file out on lt lt job contact lt lt end break case GLOBUS GRAM PROTOCOL JOB STATE PENDING break Reports state change to the user Chapter 5 Getting started with development in C C 119 case GLOBUS GRAM PROTOCOL JOB STATE ACTIVE break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE FAILED cerr Job Failed on job contact endl Monitor gt SetFailed Monitor gt setDone break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE DONE cout Job Finished on job contact endl Moni tor setDone break Reports state change to the user The next step is to submit the job itself This is achieved by calling the globus gram client register job request function that is an asynchronous or non blocking call that also needs in our example a C callback function and an ITSO CB object The request cb attribute of the class ITSO GRAM JOB will be used for this purpose The callback function used with globus gram client register job request is request callback See ITSO GRAM JOP on page 316 for implementation details It calls the method SetRequestDone of the ITSO GRAM JOB object that
126. ITSO_GRAM_JOBS_CALLBACK Monitor ITSO GRAM JOBS CALLBACK user callback arg ITSO GRAM JOB job Monitor GetJob job contact switch state case GLOBUS GRAM PROTOCOL JOB STATE STAGE IN cout Staging file in on job contact endl break case GLOBUS GRAM PROTOCOL JOB STATE STAGE OUT cout lt lt Staging file out on lt lt job contact lt lt end break case GLOBUS GRAM PROTOCOL JOB STATE PENDING break Reports state change to the user 318 Enabling Applications for Grid Computing with Globus case GLOBUS GRAM PROTOCOL JOB STATE ACTIVE break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE FAILED Monitor Remove job contact job gt SetFailed job gt setDone cerr lt lt Job Failed on lt lt job_contact lt lt end break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE DONE cout lt lt Job Finished on lt lt job contact lt lt end Monitor Remove job contact job gt setDone break Reports state change to the user static void request callback void user callback arg globus gram protocol error t failure code const char job contact globus gram protocol job state t state globus gram protocol error t errorcode ITSO GRAM JO0B Request ITSO GRAM JOB user callback arg cout Contact on the server job contact endl if failure code 0 Request gt Set
127. JobContact const_cast lt char gt job_contact else cout lt lt Error during the code submission lt lt endl lt lt Error Code lt lt failure code lt lt endl Request gt setDone Request gt SetFailed void ITSO GRAM JOB SetJobContact char c jobcontact c callback gt Add c this h bool ITSO GRAM JO0B Submit string res string rsl failed false int rc globus gram client register job request res c str rsl c_str GLOBUS GRAM PROTOCOL JOB STATE ALL callback gt GetURL GLOBUS_GRAM_CLIENT_NO_ATTR Appendix B C C source code for examples 319 itso gram jobs request callback void this if rc 0 if there is an error printf TEST gram error d s n rey translate the error into english globus_gram_client_error_string rc return true else return false h h void ITSO GRAM JOB Wait ITSO CB Wait Free up the resources of the job contact as the job is over and the contact is now useless if jobcontact NULL globus_gram_client_job_contact_free jobcontact jobcontact NULL IE Continue P void ITSO GRAM JOB Cancel int rc printf tTEST sending cancel to job manager n if rc globus gram client job cancel jobcontact 0 printf tTEST Failed to cancel job n printf tTEST gram error d s n rc globus gram client error string rc else printf tTEST job can
128. K KER KR ERR EERE RK MONITOR implements the callback mechanism used in all the Globus asynchronous mechanism a non blocking globus call register an operation and when this operation has been completed this function is call To implement this mechanism in C we need to use a static function that will a pointer to a MONITOR object as one argument This function will then be able to call the callback method of this object setDone The Class ITSO_CB will be used in all other examples It is more complete an easier to use but hide the details 182 Enabling Applications for Grid Computing with Globus The callback implies a synchronization mechanism between the calling thread and the callback To ensure thread safety and portability we use globus function to manipulate the mutex the condition variable The class attributes are a mutex of type globus mutex t and a condition variables of type globus cond t The C function globus mutex and globus cond are used to manipulate them They maps the POSIX calls Other attributes are used to store information about the result of the ope ration done or error setDone is called to indicate the operation has completed globus gass copy register handle to url It sends the signal via the condition variable Lock and Unlock locks and locks the mutex Wait waits the signal on the condition variable f E FFAR AAA ARA AA AAA RARA RA A AAA AAA AIAR RARA AAA RARA
129. L home globus JYCode other GenerateDrawsGlo bus GenerateDrawsGlobus m0 itso maya com file clean up GenerateDrawsGlobus m0 itso maya com environment LD LIBRARY PATH GLOBUS LOCATION lib Monitoring d2 itso dakota com Monitor 71 c2 itso cherokee com Monitor 66 cl itso cherokee com Monitor 61 d2 itso dakota com Monitor 100 c2 itso cherokee com Monitor 100 cl itso cherokee com Monitor 96 d2 itso dakota com Monitor 100 c2 itso cherokee com Monitor 100 cl itso cherokee com Monitor 100 D toi o K 9 2 Small Blue example 262 This example shows an example of how to distribute a function across a Grid infrastructure based on the Globus Toolkit 2 2 Note that for readability reasons not all the needed error checking is done for every Globus Toolkit 2 2 API call The purpose of the game called Puissance 4 in French is to align four chips to win In this example a simple artificial intelligence machine plays against a human The artificial intelligence is implemented in the GAME C program available in GAME Class on page 337 and works in the following ways gt It evaluates the value of each position from the first column to the eighth gt For each position it also evaluates the next positions that the adversary could possibly play and reevaluates its tested position accordingly When all positions are evaluated the best move is chosen The standalone or non gridified version of th
130. Load average queue entries and so on Storage system information Total disk space free disk space and so on Network information Network bandwidth latency measured and predicted Highly dynamic information Free physical memory free virtual memory free number of processors and so on The Grid Information Service GIS also known as the Monitoring and Discovery Service MDS provides the information services in Globus The MDS uses the Lightweight Directory Access Protocol LDAP as an interface to the resource information Monitoring and Discovery Service MDS MDS provides access to static and dynamic information of resources Basically it contains the following components Grid Resource Information Service GRIS Grid Index Information Service GIIS Information providers MDS client YYY Yy Chapter 2 Grid infrastructure considerations 23 Figure 2 1 represents a conceptual view of the MDS components As illustrated the resource information is obtained by the information provider and it is passed to GRIS GRIS registers its local information with the GIIS which can optionally also register with another GIIS and so on MDS clients can query the resource information directly from GRIS for local resources and or a GIIS for grid wide resources Request and response Host A of resource information Request and response of rasource information Request and respon
131. M CLIENT MODULE GLOBUS SUCCESS cerr lt lt Cannot start GRAM module exit 2 E the game GAME Current XSIZE YSIZE Chapter 9 Application examples 269 used to temporary store columns positions evaluation results int s l k toplay used to store human inputs char c 2 The node vector should be initialized with the value of the nodes what is missing here is the globus calls to the globus MDS server to get these values So for the exercise you can use grid info search to find 8 hosts on which you can submit your queries vector lt string gt node ask the broker to find 8 nodes itso broker GetLinuxNodes node 8 variable used in all for loops int i Here we want test the existence of the file as there is no such checking in the ITSO GLOBUS FTP CLIENT class FILE fd fopen SmallBlueSlave r if fd NULL printf Error opening local smallblueslave exit 2 else that fine lets go for FTP we can close fd descriptor because a new one will be opened for each ITSO GLOBUS FTP CLIENT object fclose fd the ITSO CB callback object is used to determine when the transfer has been completed vector ITSO GLOBUS FTP CLIENT transfer never forget to activate the Globus module you want to use globus module activate GLOBUS FTP CLIENT MODULE 8 transfer let create 8 locks string dst for i 0 i 8 i cout lt lt node i lt lt endl dst
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133. Other publications LL 367 Online resources na da secnm eene bae decree erg ee ie DS 369 How to get IBM Redbooks 0 0 cee ee 372 INGO XA s ss Sea PN Eos P ons a AVEC EcL M 373 Enabling Applications for Grid Computing with Globus Figures 1 6 2 1 2 2 2 3 2 4 2 5 2 6 3 1 3 2 3 3 3 4 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8 4 9 4 10 4 11 4 12 4 13 5 1 5 2 5 3 5 4 7 1 7 2 7 3 7 4 7 5 Possible user view of grid LL 7 Security in a grid environment 8 BrokerS IVviC suse ei de ail iaia 8 SCHEQUIEr n ewes de RIO ta 9 Data management 10 GRAM lrn IRENE 10 MDS Overview 24 Standard file transfer 27 Third party file transfer llle 27 Share job information for fault tolerance aaan anaana nanna 32 Grid portal on an application Server 35 Grid topologles ova ide ern oer Ms Rt Rr QUE eR ear URS NE 39 Parallel application flow llli 47 Serial jo IOW e cce tet ter deett Deci eo t oeste s bendi 48 Networked job flow llle RII 49 Job with sub jobs in a grid application LL 50 Federated DBMS architecture 75 Data topology of a grid 78 Independently working jobs on disjunct data subsets 81 Static input data processed by jobs with changing parameters 82 All jobs works on the same data and write on the same data set 83 Jobs with individual input data writing output into one data store 84 Sandboxing mide pe eai ec th 89 Accessing Avak
134. RAA int main int argc char argv globus_ftp_client_handle_t handle globus byte t buffer MAX BUFFER SIZE globus size t buffer length MAX BUFFER SIZE globus result t result char src char dst ELLE fd EEE EK k k e e e e e e e de e AAA KERR KR KEK KERR ERK Process the command line arguments K E He e E e e e e e e e e he ee ERK KK EKER e K A K K k kke if argc 3 printf Usage put local_file DST_URL n return ERROR else 198 Enabling Applications for Grid Computing with Globus argv 1 argv 2 src dst EEE EK RRR RRR EKER EKER KKK EERE RE Open the local source file KARR KKK KK RRA ERK KEKE KEKE REREKERE fd fopen src r if fd NULL printf Error opening local file amp s n src return ERROR BR RRR RRR ER ERE RRR EKER KK RR KR ERK EKER KEK KK RR KK ERK KERR KERR KEKE KER ERER EK Initialize the module and client handle This has to be done EVERY time you use the client library The mutex and cond are theoretically optional but highly recommended because they will make the code work correctly in a threaded build NOTE It is possible for each of the initialization calls below to fail and we should be checking for errors To keep the code simple and clean we are not See the error checking after the call to globus_ftp_client_put for an example of how to handle errors in the client library RAK KR KKK RR KK ERA K KEK KR EK KK EKER
135. REE fd fopen src r if fd NULL printf Error opening local file amp s n src return ERROR DEEE EK k H ke e de e e de e AAA AAA AAA RARA e Ske e He He e He He e He He Re KAKA RA KE ERK ERK KEK He He Se He KARA RA Initialize the module handleattr operationattr and client handle This has to be done EVERY time you use the client library if you don t use attrs you don t need to initialize them and can pass NULL in the parameter list The mutex and cond are theoretically optional but highly recommended because they will make the code work correctly in a threaded build NOTE It is possible for each of the initialization calls below to fail and we should be checking for errors To keep the code simple and clean we are not See the error checking after the call to globus_ftp_client_put for an example of how to handle errors in the client library K F He Ae H He e e He e KK e he e Ae e e ke e KEK KK Ae e He Ae e He Ae KER KR Ae he e e She e He She KEKE KEKE Ae Ske he e e He e e e e Ke ke K Ke globus module activate GLOBUS FTP CLIENT MODULE globus mutex init amp lock GLOBUS NULL globus cond init amp cond GLOBUS NULL globus ftp client handleattr init amp handle attr globus ftp client operationattr init amp attr Chapter 7 Using Globus Toolkit for data management 205 BRR RR RRR ER RRR AAA AIAR AAA RARE AAA RARA AAA AIR AAA RK ERK KER KEKE KEKE RRR ATER Set
136. RSL format based on XML 10 4 4 Reliable File Transfer Service RFT This is an OGSA based service that provides interfaces for controlling and monitoring third party file transfers using GridFTP servers It is similar to the GT2 globus url copy tool 10 4 5 Replica Location Service RLS Large sites often replicate data to provide quick and easy access to data Distributing replicas of the data reduces data access latency RLS maintains a registry of information about where replica data resides and makes it easy to find data locations 10 5 Summary Fundamentally the Globus Toolkit V3 will be a Web service based variation of Globus Toolkit 2 All components like GRAM and GridFTP will remain But the infrastructure will change to use Web services Globus Toolkit V8 implements Java wrappers to the Globus Toolkit 2 components and implements new functionality RSL and proxy certificate formats are slightly modified to adopt some new standards but some tools or translators are provided for an easy migration from the Globus Toolkit 2 to the Globus Toolkit V3 The Globus Toolkit V3 will provide an implementation both in Java and in C and a client API will be provided in C Java and Python Applications developed with Globus Toolkit 2 should be easily portable to Globus Toolkit V3 296 Enabling Applications for Grid Computing with Globus Grid qualification scheme In this appendix criteria are presented that may be used as a starti
137. SO GASS TRANSFER This class provides methods to easily transfer a file from one location to another The GLOBUS FILE class is use to refer to a locally stored file and GLOBUS URL is used to refer to a remotely stored file that can be reached by either http https or gsiftp protocol The method setURL of the GLOBUS URL class is used to define the URL The method Transfer of the ITSO GASS TRANSFER class executes the transfer and the two arguments are respectively the source file and the destination file The two arguments can either be of GLOBUS FILE or GLOBUS URL type The Transfer is non blocking so the Wait method should be called later in the code to wait for the completion of the transfer itso gass copy h ifndef ITSO GASS COPY H define ITSO GASS COPY H include globus_common h include globus_gass_copy h include itso_cb h include lt cstdlib gt include lt cstdio gt include lt iostream gt include lt cstring gt include lt string gt class GLOBUS FILE globus io handle t io handle int file fd public GLOBUS FILE GLOBUS FILE char GLOBUS FILE globus io handle t GLOBUS FILE get globus io handle h class GLOBUS URL 306 Enabling Applications for Grid Computing with Globus globus url t url globus gass copy url mode t url mode char URL public GLOBUS URL GLOBUS URL bool setURL char destURL bool setURL string destURL globus gass
138. SUCCESS cerr lt lt url copy error lt lt globus object printable to string error lt lt endl monitor setError error moni tor setDone return h ITSO_GASS_TRANSFER ITSO_GASS_TRANSFER handlers initialisation first the attributes then the handler globus gass copy handleattr init amp gass copy handleattr globus gass copy handle init amp gass copy handle amp gass copy handleattr h ITSO GASS TRANSFER ITSO GASS TRANSFER globus gass copy handle destroy amp gass copy handle if source url mode GLOBUS GASS COPY URL MODE FTP globus libc free source ftp attr if dest url mode GLOBUS GASS COPY URL MODE FTP globus libc free dest ftp attr if source url mode GLOBUS GASS COPY URL MODE GASS globus libc free source gass attr if dest url mode GLOBUS GASS COPY URL MODE GASS globus libc free dest gass attr void ITSO GASS TRANSFER setSource GLOBUS URL amp source url Appendix B C C source code for examples 309 globus_gass_copy_attr_init amp source_gass_copy_attr source_url_mode source_url getMode if source url mode GLOBUS GASS COPY URL MODE FTP source ftp attr globus ftp client operationattr t globus libc malloc sizeof globus ftp client operationattr t globus ftp client operationattr init source ftp attr globus gass copy attr set ftp amp source gass copy attr source ftp attr else if source url mode GLOBUS
139. TE newgame Play col WHITE newgame Inverse 1 0 for int k 1 K XSIZE 1 k s newgame Value k BLACK if s gt 1 1 s h start 1 return start main GAME Current XSIZE YSIZE int s l k toplay char c 2 while true Current Display do cout lt lt cin gt gt C c 1 0 l atoi c while 1 lt 1 1 gt XSIZE Current CanPlay 1 Current Play 1 BLACK if Current HasWon 1 BLACK Current Display exit 1 E 1 100000 for k 1 k XSIZE 1 k if Current CanPlay k Appendix B C C source code for examples 331 s Simulate Current k if s gt 1 1 s toplay k h h hs if 1 100000 cout lt lt NULL lt lt end exit 1 h Current Play toplay WHITE if Current HasWon toplay WHITE Current Display exit 1 Ms h h SmallBlueMaster C define GNU SOURCE mandatory to use get current dir name include lt unistd h gt include globus_common h include globus_gass_server_ez h include itso_gram_jobs_callback h include itso_globus_ftp_client h include lt vector gt include lt iostream gt include broker h include itso_gass_server h include GAME C using namespace itso_gass_ server using namespace std main Start a GASS server locally that will listen on 10000 port all the results of the evualtion We will stop it at the end It cannot be defined as a standalone class because the s
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141. Tivoli License Manager 65 topology considerations 38 transaction 58 transfer agent 88 types of grids 3 U URLCopy 154 usability requirements 59 V virallicense 64 virtual computer 3 Virtual Data Toolkit 103 W web services 5 66 WebSphere 7 33 34 wrapper script 111 WSDL 292 X XML 6 58 Index 377 378 Enabling Applications for Grid Computing with Globus Redbooks Enabling Applications for Grid Computing with Globus Enabling Applications for Grid Computing with Globus Enable your applications for grid computing Utilize the Globus Toolkit Programming hints tips and examples This IBM Redbook a follow on to Introduction to Grid Computing with Globus SG24 6895 discusses the issues and considerations for enabling an application to run in a grid environment Programming examples are provided based on the Globus Toolkit V2 2 The first part of this publication addresses various considerations related to grid enabling an application from the perspective of the infrastructure the application and the data requirements The second part of this publication provides many programming examples in C C and Java to help solidify the concepts of grid computing and the types of programming tasks that must be handled when developing an application intended to run in a grid environment SG24 6936 00 ISBN 0738453331 S Redbooks INTERNATIONAL TECHNICAL SUPPORT ORGANIZATI
142. a globus io handle globus io file posix convert file fd GLOBUS NULL io handle h GLOBUS_FILE GLOBUS_FILE close file fd globus libc free io handle E globus_io_handle_t GLOBUS_FILE get_globus_io_handle return io_handle h GLOBUS URL GLOBUS URL GLOBUS _URL GLOBUS URL free URL F bool GLOBUS_URL setURL char destURL check if this is a valid URL if globus url parse destURL amp url GLOBUS SUCCESS cerr can not parse destURL destURL endl return false determine the transfer mode if globus gass copy get url mode destURL amp url mode GLOBUS SUCCESS cerr failed to determine mode fmeor destURL destURL endl return false h URL strdup destURL return true F bool GLOBUS_URL setURL string url return setURL const_cast lt char gt url c_str globus gass copy url mode t GLOBUS URL getMode return url mode bs char GLOBUS_URL getScheme return url scheme 308 Enabling Applications for Grid Computing with Globus char GLOBUS URL getURL return URL BREE RRR RRR RR eke ER ERE RR KK ERK KK RK ERK ERK ARA AAA RA AAA AAA RAI addi debeat I namespace itso gass copy static void url copy callback void callback arg globus gass copy handle t handle globus object t error globus bool t use err GLOBUS FALSE ITSO CB monitor ITSO CB callback arg if error GLOBUS
143. a job gsiclient2 to t2 itso tupi com that will try to communicate with a server already running on mO itso maya com gsiserver2 This process will print He11o World as soon as the message is received The two processes will use mutual authentication which means that they need to run with the same credentials on both hosts By using the gatekeeper the submitted job will use the same credentials as the user that submitted the job The communication will be securely authenticated between the two hosts The communication is also encrypted We use the globus io attr set secure protection mode call to activate encryption mO itso maya com t2 itso tupi com submission globus credentials globus credentials delegation Hello World secured authenticated socket communication Figure 7 3 Using globus io for secure communication To compile the two programs 1 First create the Makefile header with globus makefile header flavor gcc32 globus io globus gss assist globus header 172 Enabling Applications for Grid Computing with Globus 2 Use the following Makefile to compile include globus_header all gsi gsisocketclient gsisocketserver gsisocketclient gsisocketclient C g g o gsisocketclient GLOBUS CPPFLAGS GLOBUS LDFLAGS gsisocketclient C GLOBUS PKG LIBS gsisocketserver gsisocketserver C g g 0o gsisocketserver GLOBUS CPPFLAGS GLOBUS LDFLAGS gsisocketse
144. a set on local storage for faster access Replica management is the process of keeping track of where portions of the data set can be found Globus Replica Management integrates the Globus Replica Catalog for keeping track of replicated files and GridFTP for moving data and provides replica management capabilities for grids Application enablement considerations Data management Data management is concerned with collectively maximizing the use of the limited storage space networking bandwidth and computing resources The following are some of the data management issues that need to be considered in application design and implementation Dataset size For large datasets it is not practical and may be impossible to move the data to the system where the job will actually run Using data replication or otherwise copying a subset of the entire dataset to the target system may provide a solution gt Geographically distributed users data computing and storage resources If your target grid is geographically distributed with limited network connection speeds you must take into account design considerations around slow or limited data access Data transfer over wide area networks Take into account the security reliability and performance issues when moving data across the Internet or another WAN Build the required logic to handle situations when the data access may be slow or prevented gt Scheduling of data transfers
145. abase are also well suited for grid environments At some point the question usually arises as to whether a problem should be solved in a grid or whether other approaches like HPC Storage Tanks and so on are sufficient In order to decide on the best choice there are a number of aspects to consider from various perspectives This chapter provides some basic ideas for dealing with the types of jobs and data in a grid This chapter also provides an overview of criteria that helps determine whether a given application qualifies for a grid solution These criteria are discussed in four sections dealing with job application data and usability and non functional perspectives Together they allow a sufficient understanding of the complexity scope and size of the grid application under consideration It also allows the project team to detect any show stoppers and to size the effort and requirements needed to build the solution 44 Enabling Applications for Grid Computing with Globus 3 1 Jobs and grid applications In order to have a clearer understanding of the upcoming discussion we introduce the following terminology Grid Application A collection of work items to solve a certain problem or to achieve desired results using a grid infrastructure For example a grid application can be the simulation of business scenarios like stock market development that require a large amount of data as well as a high demand for computing resources in o
146. agement 1 3 6 Job and resource management With all of the other facilities we have just discussed in place we now get to the core set of services that help perform actual work in a grid environment The Grid Resource Allocation Manager GRAM provides the services to actually launch a job on a particular resource check on its status and retrieve its results when it is complete Broker A MDS Directory Service Portal Scheduler NM ud E Execute job get ei GRAM status result WIL MI Figure 1 6 GRAM 10 Enabling Applications for Grid Computing with Globus 1 3 7 Other There are other facilities that may need to be included in your grid environment and considered when designing and implementing your application For instance inter process communication and accounting chargeback services are two common facilities that are often required We will not discuss these in detail in this publication but they are certainly important considerations 1 4 Job flow in a grid environment In the preceding section we provided a brief and high level view of the primary components of a grid environment As you start thinking about enabling an application for a grid environment it is important to keep in mind these components and how they relate and interact with one another Depending on your gr
147. ales Enablement IBM Somers Rob High WebSphere Chief Architect and Distinguished Engineer IBM Austin Susan Malaika IBM Senior Technical Staff Member IBM Silicon Valley Lab Jean Pierre Prost Grid Expert at the IBM Grid Design Center for eBusiness on Demand IBM Montpellier Duane Quintern IBM Global Services Masanobu Takagi Web Technologies Technical Practice Competency Management IGS Japan Julie Czubik International Technical Support Organization Poughkeepsie Center Preface xv Become a published author Join us for a two to six week residency program Help write an IBM Redbook dealing with specific products or solutions while getting hands on experience with leading edge technologies You ll team with IBM technical professionals Business Partners and or customers Your efforts will help increase product acceptance and customer satisfaction As a bonus you ll develop a network of contacts in IBM development labs and increase your productivity and marketability Find out more about the residency program browse the residency index and apply online at ibm come redbooks residencies html Comments welcome Your comments are important to us We want our Redbooks to be as helpful as possible Send us your comments about this or other Redbooks in one of the following ways gt Use the online Contact us review redbook form found at ibm com redbooks Send your comments in an Internet note to redbook us ibm
148. ally as the applications often require certain OS conditions and application settings or very often when installing on Windows a reboot needs to be executed This makes a standard application in many cases quite difficult to handle on a grid but does not exclude them As advances in autonomic computing provide for self provisioning there will be less restrictions in this area Using standard software as jobs within a grid could raise licensing issues either due to the desire to have the application installed on many different nodes in the grid or related to single user versus multi user license agreements We discuss more on licenses in a grid environment in 3 12 1 Software license considerations on page 62 3 3 3 Parallel applications 52 Applications that already have a parallel application flow such as those that have been designed to run in a cluster environment may already be suited to run in a grid environment In order to allow a grid server or grid portal to take the most advantage of these there needs to be identifiable and accessible handles to the inner functions jobs of such a parallel application If this is not the case such an application can only be handled as one unit similar to a standard application However it makes sense to include such an application in a grid if the overall Enabling Applications for Grid Computing with Globus task requires more than the resources available in a given cluster This means tha
149. an attacker in the middle The Grid Portal Development Kit GPDK provides a Java Bean that provides GSlssh protocol facilities to a Java application used in a Web portal For more information see http doesciencegrid org projects GPDK runs remote command GSI openssh server copy files proxy credentials proxy credentials gt delegation generates grid init proxy Figure 5 1 GSl enabled OpenSSH architecture The installation procedure as well as a complete example is provided in GSIssh installation on page 116 114 Enabling Applications for Grid Computing with Globus gsissh is used the same way as ssh It cannot use Globus URLs consequently files must be staged in and out using gsiscp or sftp The executable must be present on the remote host before execution Below are a few examples Example 5 9 gsissh example globus m0 globus grid proxy init Your identity 0 Grid 0 Globus OU itso maya com CN m0user Enter GRID pass phrase for this identity Creating DroXy susce sese reete nne PURI ete NUR Te Re ia Done Your proxy is valid until Tue Mar 18 04 33 21 2003 globus m0 globus gsissh tl date hostname Mon Mar 17 10 33 33 CST 2003 tl itso tupi com The gsissh command also embeds and secures the X11 protocol that allows the user to remotely run an application that will be displayed on the local X server This example runs the Linux monitoring softwa
150. anages the callback as well as the C function that will call the callback object are passed as an arguement f BRRRR RRR RRR RR eke ER he ke ERR KERR KK RRR KR ERK ERK EKER ER ERE RRR KERR KR RK ERR EERE class GASS_TRANSFER globus gass copy handle t gass copy handle globus gass copy handleattr t gass copy handleattr globus gass transfer requestattr t dest gass attr globus gass copy attr t dest gass copy attr public GASS TRANSFER handlers initialisation first the attributes then the gass copy handler globus gass copy handleattr init amp gass copy handleattr globus gass copy handle init amp gass copy handle amp gass copy handleattr E void setDestination GLOBUS URL amp dest url dest gass attr globus gass transfer requestattr t globus libc malloc sizeof globus gass transfer requestattr t globus gass transfer requestattr init dest gass attr dest url getScheme And We use GASS as transfer globus gass copy attr init amp dest gass copy attr globus gass copy attr set gass amp dest gass copy attr dest gass attr bs void setBinaryMode globus gass transfer requestattr set file mode dest gass attr GLOBUS GASS TRANSFER FILE MODE BINARY bs void startTransfer GLOBUS FILE amp globus source file GLOBUS URL destURL MONITOR amp monitor globus result t result globus gass copy register handle to url amp gass copy handle globus source file get globus io handle de
151. aseline guidance to the user interface developers on user interface design gt Establish performance standards for usability evaluations Define test scenarios for usability test plans and usability testing Some of the typical usability requirements established for an IT solution play a role and include gt Tailorability What requirements exist for the user to customize the interface and its components to allow optimization based on work style personal preferences experience level locale and national language gt Efficiency How will the application minimize task steps simplify operations and allow end user tasks to be completed quickly 3 11 2 Usability requirements for grid solutions Grid solutions must address usability requirements recognizing a variety of user categories that may include gt End users wishing to Log in to the grid submit applications to the grid query status and view results Owners users of donor machines Administrators and operators of the grid Chapter 3 Application architecture considerations 59 Consequently the typical steps followed to identify these requirements for any solution should continue to be followed when creating a grid solution In addition the following items may influence the design of grid solutions Installation Ease of installation should provide automatic installation by a non technical person rather than a systems programmer with the need to modify scr
152. at this total amount of data may exceed the amount of data input and output of the grid application as there can be a series of sub jobs that produce data for consumption of other sub jobs and so forth until finally the resulting data of the application are produced For permanent storage the grid user needs to be able to locate where in the grid the required storage space is available Other temporary data sets that may need to be copied from or to the client also need to be considered 76 Enabling Applications for Grid Computing with Globus 4 1 6 Network bandwidth The amount of data that has to be transported over the network can be restricted by available bandwidth Less bandwidth requires a rather careful planning of the expected data traffic within a grid application at runtime Compression and decompression techniques are useful to reduce the data amount to be transported over the network But in turn it raises the issue of consistent techniques on all involved nodes This may exclude the utilization of scavenging for a grid if there are no agreed standards universally available The central question is What bandwidth is needed to allow all required input and output data of the jobs to be transported over the network 4 1 7 Time sensitive data Another issue to be covered in this context is time sensitive data Some data may have a certain lifetime meaning its values are only valid during a defined time period The jobs in a g
153. ata spaces are often needed During planning of the grid application the forms and amount of temporary data space should be considered Points to consider include Availability of sufficient data space for the amount of data a job or the federated system requires Also caches managed by the grid server or grid portal should be considered gt OS specific requirements for data spaces data access and management need to be taken care of especially if the job specific data needs to be or can be local to the job or whether cross system network or platform data access has to be planned The format access and locking of data can vary if not indirectly accessed gt Local or shared file system dependent requirements are to be considered to assure for optimal runtime access gt Memory for temporary data of a job can vary from system to system as a node may run several jobs in parallel and share the memory for many processes In order to allow the best performance and avoid unnecessary data swapping the memory requirements of the jobs are important to understand In the case of compiled executables there may be different memory needs depending on the compiler and operating system it is compiled for 4 1 5 Size of data Knowing separating and compiling the amount of data within a grid application is important The total amount of data includes all data used for input and output of all jobs within the grid application Note th
154. atekeeper or xinet daemons for grid services A factory will also have an associated registry to keep track of these instances and enable discovery The OGSA defines registries as places to store various kinds of information about grid resources gt Instances The GSH is just a minimal name in the form of a URI and does not carry enough information to allow a client to communicate directly with the service instance Instead a GSH must be mapped to a Grid Service Reference GSR via the registry gt Stateful A grid service instance has a state A process can be initiated via a method call on a service port type and its state checked at a later time using the GSR A GSR contains all information that a client may require to communicate with the service via one or more protocols While a GSH is valid for the entire lifetime of the grid service instance a GSR may become invalid therefore requiring a client to use the mapping service to acquire a new GSR appropriate to a particular binding using the GSH A GSR is encoded using WSDL so that a WSDL document should be the minimal information required to fully describe how to reach the particular grid service instance Globus Toolkit V3 is roughly the Globus Toolkit 2 that uses OGSA architecture to make its components available via Web services Enabling Applications for Grid Computing with Globus 10 4 Globus grid services The following sections describe a few of the services that will b
155. ay take the entire time to recover from a failure such as network outages 2 2 2 Reliability Reliability is always an issue in computing and the grid environment is no exception The best method of approaching this difficult issue is to anticipate all Chapter 2 Grid infrastructure considerations 37 possible failures and provide a means to handle them The best reliability is to be surprise tolerant The grid computing infrastructure must deal with host interruptions and network interruptions Below are some approaches to dealing with such interruptions Checkpoint restart While a job is running checkpoint images are taken at regular intervals A checkpoint contains a snapshot of the job states If a machine crashes or fails during the job execution the job can be restarted on a new machine using the most recent checkpoint image In this way a long running job that runs for months or even years can continue to run even though computers fail occasionally Persistent storage The relevant state of each submitted job is stored in persistent storage by a grid manager to protect against local machine failure When the local machine is restarted after a failure the stored job information is retrieved The connection to the job manager is reestablished Heartbeat monitoring In a healthy heartbeat a probing message is sent to a process and the process responds If the process fails to respond an alternate process may be probed The alte
156. b vector lt string gt iterator i for i Nodes begin i Nodes end i cout lt lt Try to submit on lt lt i lt lt end job Submit i amp executable bin hostname job Wait if job HasFailed break h globus module deactivate GLOBUS GRAM CLIENT MODULE Here is the result when a1 and c2 are down globus m0 JYCode SureJob Try to submit on al itso apache com Contact on the server https al itso apache com 48181 27222 1047945694 Job Failed on https al itso apache com 48181 27222 1047945694 Try to submit on c2 itso cherokee com Contact on the server https c2 itso cherokee com 40304 20728 1047945691 Job Failed on https c2 itso cherokee com 40304 20728 1047945691 Try to submit on cl itso cherokee com Contact on the server https cl itso cherokee com 47993 25310 1047945698 Job Finished on https cl itso cherokee com 47993 25310 1047945698 5 2 5 Simple broker 124 A user application should not have to care about locating the resources it needs It just needs to describe to a broker the kind of resources it will use to run the applications Operating systems SMP number of nodes available applications available storage and so on This task needs to be done at the application level via a component called a broker that can be implemented in the application itself or as a service that will be queried by the applications The Globus Toolkit 2 2 does not provide a broker implementa
157. b ID obtained from the job submission is input to the doGetStatus method When the job is running the job status ACTIVE is returned When the job completes the job status DONE is returned Example 8 8 Sample code to get job status from Web portal public String doGetStatus String jobId String cmdResult null String subCmd globus job status jobId try String cmd bin su c subCmd mOuser cmdResult doRun cmd catch IOException e System out print n doGetStatus e 234 Enabling Applications for Grid Computing with Globus return cmdResult 0 Get application run results The sample code to get the run result is shown in Example 8 9 The job ID obtained at job submission is used as input The run results are cached after the job completes and returns Example 8 9 Sample code to get job output from Web portal public String doGetResult String jobId String cmdResult null String subCmd globus job get output jobId try String cmd2 bin su c subCmd mOuser cmdResult doRun cmd2 catch IOException e System out print n doGetResult e return cmdResult Cancel or clean a job Use globus job cancel jobId to kill a running job The job ID is obtained when the job is submitted The cached output from the job is not removed Use globus job clean jobIdto kill a job if it is running and to remove the cached output on the ex
158. bal License Broker This product runs on AIX HP UX Compaq Alpha and IRIX It uses Globetrotter FLEXIm 7 1 as described in FLEXIm on page 64 More details on Platform Global License Broker is available on the Internet at http www platform com products wm glb index asp General license management considerations When designing and deploying grid enabled applications it is important to understand any licensing requirements for required runtime modules If designing a broker or utilizing MDS to identify possible target resources on which to run the application the existence or applicability of any required software licenses should be taken into account 3 12 2 Grid application development In order to develop a grid application the Globus Toolkit offers a broad range of services that are becoming more comprehensive with the next version Included are commodity Grid Kits CoG for a number of programming languages and models such as Java C C Perl Python Web services CORBA and Matlab see http www globus org cog for details and updates Grid Computing Environment GCE The Globus Toolkit CoGs and appropriate application development tools form a Grid Computing Environment capable of supporting collaborative development of grid applications In context with the Globus initiative various frameworks for collaborative and special industry solutions as well as a grid services flow language are being worked on For details and r
159. ber attr NULL attr ldap next attribute ldap server entry ber values ldap get values ldap server entry attr answer strdup values 0 ldap value free values if strcmp Mds Host hn attr 0 hostname answer if strcmp Mds Cpu Free 15minX100 attr 0 cpu atoi answer if strcmp Mds Cpu Total count attr 0 cpu nbzatoi answer if strcmp Mds Cpu speedMHz attr 0 speed atoi answer printf s s n attr answer check if we can really use this node if globus_gram_client_ping hostname c_str Chapter 5 Getting started with development in C C 129 nodes push back new Host hostname speed cpu_nb cpu 100 h Only valid nodes that are available are selected The globus gram client ping function from the globus gram client API is used for this purpose We also calculate a weight for each node speed cpu nb cpu 100 The higher the weight is the higher our ranking of the node will be The broker will return the best nodes first as shown in Example 5 21 Example 5 21 Check the host if globus gram client ping hostname c str nodes push back new Host hostname speed cpu nb cpu 100 In a real environment the broker should take into account a variety of factors and information Not all of the information has to come from MDS For instance some other factors that might affect the broker s choice of resources could be Service level agreements Time range
160. ble to a remote host The transfer is achieved via the ITSO GLOBUS FTP CLIENT class and its transfer method The source code is available in itso globus ftp client C on page 313 9 2 2 Implementation We will use three C classes that wrap Globus C calls gt ITSO CB will be used as generic callback type for all globus functions that need a callback Note that these objects are always called from a static C function whose one argument is the object itself ITSO CB implements the mutex condition variables synchronization mechanism always used with the Globus Toolkit 2 non blocking or asynchronous functions ITSO GRAM JOB and ITSO GLOBUS FTP CLIENT both derive from ITSO CB See ITSO CP on page 315 and its explanation in Callbacks on page 109 gt ITSO GRAM JOB will be used to submit a job See ITSO GRAM JOP on page 316 gt ITSO GLOBUS FTP CLIENT which is a wrapper class to the C globus client ftp functions will perform a transfer from a file stored in a storage server to a remote URL See ITSO GLOBUS FTP CLIENT on page 311 The complete source code of the two programs is available in SmallBlue example on page 331 StartGASSServer and StopGASSServer are the two functions respectively used to start and stop the local GASS server that will retrieve the result of the evaluation nodes The source code is provided in StartGASSServer and StopGASSServer on page 324 268 Enabling Applications for Grid Computin
161. bstitution to create variables within the RSL string The getVariables method gets all of the variables declared within rsl substitution while the get method gets the value for the specified variable In this case the value for the variable EXECDIR is bin Example 6 16 RSL example 5 of 6 add new rs string ListRslNode rslTree new ListRslNode RslNode AND NameOpValue nv null List vals null rslTree add new NameOpValue executable NameOpValue EQ bin date rslTree add new NameOpValue maxMemory NameOpValue LTEQ 5 rslTree add new NameOpValue arguments NameOpValue EQ new String H 45M 5S nv rslTree getParam EXECUTABLE System out print ln The executable you have added is nv nv rslTree getParam MAXMEMORY System out println The memory you have added is nv nv rslTree getParam ARGUMENTS System out print ln The arguments you have added is nv System out printIn Example 6 16 uses the ListRsINode class to create attributes The add method creates a new RSL string In this case the RSL string contains the executable bin date the maxMemory 5 MB and arguments H M S These values are then stored in NameOpValue Example 6 17 RSL example 6 of 6 remove attribute from string ListRslNode node null attribs new RslAttributes myrslstring2 System out print n Your rs string is attribs toRSL try n
162. bus translate the error into english globus gram client error string rc exit 1 ifdef CANCEL sleep 3 printf tTEST sending cancel to job manager n if rc globus gram client job cancel job contact 0 printf tTEST Failed to cancel job n printf tTEST gram error d s n rc globus gram client error string rc return 1 else printf tTEST job cancel was successful n endif Wait until there is a callback saying there was a termination either successful or failed We lock the Monitor again so as to ensure that no one else tampers with it Then we wait until the condition is signaled by the callback function When it is signaled and Monitor done is set to GRAM TRUE these two things always happen in conjunction in our callback func Then we unlock the monitor and continue the program globus mutex lock 8Monitor mutex while Monitor done Within the cond wait function it unlocks the monitor allowing the callback func to take the lock When it gets a cond_signal it re locks the monitor and returns to this program But DO NOT unlock the monitor yourself use the globus gram cond wait function as it insures safe unlocking FF F X xf globus cond wait S amp Monitor cond amp Monitor mutex endwhile globus mutex unlock amp Moni tor mutex Remove Monitor Given that we are done with our monitor it has alr
163. but restricts modifying it All derivative work must be under the same LGPL or GPL The definition of this license type can be found at http www opensource org licenses 1lgpl license php GNU GPL IBM Public License persistent and viral license The GNU General Public License GPL as well the IBM Public License PL shows a persistent and viral model which means that it allows free distribution and modifying but all bundled and derivative work must be under GNU GPL as well The GNU GPL can be found at either of the following Web sites http www gnu org copyleft gpl html http opensource org licenses gpl license php The IBM PL can be found at http www opensource org licenses ibmp php For Open Source Initiative OSI certified licenses and approvals visit http opensource org docs certification_mark php For the OSI portal simply go to http ww opensource org There is a list of all approved open source licenses at the following Web site GPL LGPL BSD and MIT are the most commonly used so called classic licenses http ww opensource org licenses License management tools In order to manage most of these license models in a network there are a number of license management tools available These tools assure that all software that is included in a network or a grid application is properly used according to its license agreements Most of the license manager providers offer an SDK with APIs for various
164. catch IOException e System out printIn doGetStatus e return cmdResult 0 public String doGetResult String jobId String cmdResult null String subCmd globus job get output jobId try String cmd2 bin su c subCmd mOuser cmdResult doRun cmd2 catch IOException e System out printIn doGetResult e 242 Enabling Applications for Grid Computing with Globus return cmdResult public String doRun String cmd throws IOException ArrayList cmdOutput Process p InputStream cmdOut BufferedReader brOut InputStream cmdErr BufferedReader brErr String line cmdOutput new ArrayList p Runtime getRuntime exec cmd cmdOut p getInputStream brOut new BufferedReader new InputStreamReader cmdOut get the command output cmdOutput clear while line brOut readLine null cmdOutput add line cmdErr p getErrorStream brErr new BufferedReader new InputStreamReader cmdErr get error message while line brErr readLine null cmdOutput add line try p waitFor catch InterruptedException e System out print n Command cmd interrupted e return String cmdOutput toArray new String 0 Chapter 8 Developing a portal 243 8 3 Summary This chapter has provided examples and tips for creating a Web portal that cold be used as an interface for a grid environment It is mean
165. catch Throwable theException uncomment the following line when unexpected exceptions are occuring to aid in debugging the problem theException printStackTrace throw new ServletException theException private void submitApplication if appselect 0 equals weather submitWeather else if appselect 0 equals gene submitGene else if appselect 0 equals test submitTest else if appselect 0 equals demo submitDemo else invalidSelection private void submitWeather Add code to submit the weather application here private void submitGene Chapter 8 Developing a portal 227 Add code to submit the gene application here f private void submitTest Add code to submit the test application here private void submitDemo Add code to submit the demo application here private void getResult Add code to get the Application results here private void getStatus Add code to get the Application status here gi private void doLogout System out println doLogout forwarding to login page try RequestDispatcher rd getServletContext getRequestDispatcher login html rd forward req res catch javax servlet ServletException e System out printIn e catch java io IOException e System out printIn e private v
166. cation must ensure that the appropriate target resource s are used Some of the items to consider include gt Choosing the appropriate resource By working in conjunction with the broker ensure that an appropriate target resource is selected This requires that the application accurately specifies the required environment operating system processor speed memory and so on The more the application developer can do to eliminate specific dependencies the better the chance that an available resource can be found and that the job will complete Multiple sub jobs If an application includes multiple jobs the designer must understand and maybe reduce their interdependencies Otherwise they will have to build logic to handle items such as Inter process communication Sharing of data Concurrent job submissions gt Accessing job results If a job returns a simple status or a small amount of output the application may be able to simply retrieve the data from stdout and stderr However the capturing of that output will need to be correctly specified in the RSL string that is passed to the globusrun command If more complex results must be retrieved the GASS facility may need to be used by the application to transfer data files Job management GRAM provides mechanisms to query the status of the job as well as perform operations such as cancelling the job The application may need to utilize these capabilities to
167. cel was successful n E void ITSO_GRAM_JOB SetFailed failed true h 320 Enabling Applications for Grid Computing with Globus bool ITSO GRAM JOB HasFailed return failed B ITSO GRAM JOBS CALLBACK ITSO GRAM JOBS CALLBACK globus mutex init amp JobsTableMutex ITSO NULL globus gram client callback allow itso gram jobs callback func void this amp callback contact cout Gram contact callback contact endl h char ITSO GRAM JOBS CALLBACK GetURL return callback contact ITSO_GRAM_JOB ITSO_GRAM_JOBS_CALLBACK GetJob char s return JobsTable s ITSO GRAM JOBS CALLBACK ITSO GRAM JOBS CALLBACK cout callback contact destroyed endl globus gram client callback disallow callback contact globus free callback contact globus mutex destroy amp JobsTableMutex E void ITSO GRAM JOBS CALLBACK Add string jobcontact ITSO GRAM JOB job Lock JobsTable jobcontact job UnLock h void ITSO GRAM JOBS CALLBACK Remove char jobcontact Lock JobsTable erase jobcontact UnLock h void ITSO GRAM JOBS CALLBACK Lock globus mutex lock amp JobsTableMutex void ITSO GRAM JOBS CALLBACK UnLock globus mutex unlock amp JobsTableMutex bs itso_gram_job C include itso_gram_job h namespace itso_gram_job Appendix B C C source code for examples 321 static void callback func void user callback ar
168. certificate PrivateKey userKey null GlobusCredential proxy null ProxyCertInfo proxyCertInfo null int bits 512 int lifetime 3600 12 int proxyType Environment Setup CoGProperties properties CoGProperties getDefault Chapter 6 Programming examples for Globus using Java 135 String proxyFile properties getProxyFile String keyFile properties getUserKeyFile String certFile properties getUserCertFile The private key is encrypted in the keyfile Using the OpenSSL libraries we can load the private key and decrypt by providing a password The CA public key can be loaded using the CertUtils class Example 6 2 Creating a proxy 2 of 3 public void createProxy throws Exception System out println Entering createProxy loading certificate System out printIn Loading Certificate certificate CertUtil loadCertificate certFile String dn certificate getSubjectDN getName System out print n Your identity dn loading key System out print n Loading Key OpenSSLKey sslkey new BouncyCastleOpenSSLKey keyFile if sslkey isEncrypted String pwd null pwd Util getInput Enter GRID pass phrase sslkey decrypt pwd userKey sslkey getPrivateKey In order to create the proxy we will create a new certificate using our private key This certificate is marked to be a proxy and it has a lifetime It is important to note the proxyType variable wh
169. ch job needs to have its own copy of the game This behavior is also present in the function Simulate where a new object GAME called newgame is created specifically for the evaluation and used to store successive tested positions Therefore the game data must be replicated on all execution nodes 9 2 1 Gridification To gridify this application we will use two programs Onecalled SmallBlueMaster that will submit the job gather the results and be the interface with the human player Onecalled SmallBlueSlave that will perform the simulation and returns the result to SmallBlueMaster The source code for these two programs is available in SmallBlueMaster C on page 332 and SmallBlueSlave C on page 336 Chapter 9 Application examples 265 smallbluemaster asks each node to evaluate a position smallblueslave gather the results and decides perform the Simulate function returns the value Figure 9 4 Gridified SmallBlue One problem is that the simulate function uses two variables and returns one value that needs to be passed to and retrieved from a remote host We cannot use inter process communications between the nodes A solution is to serialize objects by storing the instance value on disk and use the Globus Toolkit 2 2 data movement functions By using GRAM and GASS systems The Current object will be serialized to disk and transferred to each remote host The tested position will be passed
170. col The gSOAP project is also used for the C implementation of the Globus Toolkit V3 For more information see http www cs fsu edu engelen soap htm Three SOAP services are defined A Base service for standard operations an Admin service for administrative access and an Info service for information on the database and its tables Spitfire is still a beta project For more information see http spitfire web cern ch Spitfire 4 2 15 Data brokering One data brokering solution available today is the Storage Resource Broker Storage Resource Broker The Storage Resource Broker SRB developed by the San Diego SuperComputer Center is not part of the Globus Toolkit but can use its GSI PKI authentication infrastructure Consequently an SRB and a Globus grid can 100 Enabling Applications for Grid Computing with Globus coexist with the same set of users SRB brings to Globus the ability of submitting metadata queries that permits a transparent access to heterogeneous data sources The SRB API does not use the globus io API nor Globus gass or GridFTP The SRB is a middleware that provides a uniform interface for connecting to heterogeneous data resources over a network and accessing replicated data sets SRB permits an application to transparently access logical storage resources whatever their type may be It easily manages data collection stored on different storage systems but accessed by applications via a global name space It
171. com Mail your comments to IBM Corporation International Technical Support Organization Dept JN9B Building 003 Internal Zip 2834 11400 Burnet Road Austin Texas 78758 3493 xvi Enabling Applications for Grid Computing with Globus Introduction Grid computing is gaining a lot of attention within the IT industry Though it has been used within the academic and scientific community for some time standards enabling technologies toolkits and products are becoming available that allow businesses to utilize and reap the advantages of grid computing As with many emerging technologies you will find almost as many definitions of grid computing as the number of people you ask However one of the most used toolkits for creating and managing a grid environment is the Globus Toolkit Therefore we will present most of our information and concepts within the context of the Globus Toolkit Note that though most of our examples and testing were accomplished in a Linux environment grid computing in general implies support for multiple platforms and platform transparency It is recommended that the first publication in this series ntroduction to Grid Computing with Globus SG24 6895 be used as a companion to this publication as many of the concepts and details of the Globus Toolkit provided in the first book will not be duplicated here The first part of this book discusses considerations related to what kind of applications are good cand
172. combined model A simple implementation of a push model could be built where the work is sent to grid resources in a round robin fashion However this model does not consider the job queue lengths If each grid resource is sent the same number of jobs a long job queue could build up in some slower machines or a long running job could block others from starting if not carefully monitored One solution may be to use a weighted round robin scheme In the pull model the grid resources take the jobs from a job queue In this model synchronization and serialization of the job queue will be necessary to coordinate the taking of jobs by multiple grid resources Local and global job queue strategies are also possible In the local pull model strategy each group of grid resources is assigned to take jobs from a local job queue In the global pull model strategy all the grid resources are assigned the same job queue The advantage of the local pull model is the ability to partition the grid resources For example proximity to data related jobs or jobs of certain types requiring similar resources may be controlled in this way Chapter 2 Grid infrastructure considerations 31 32 A combination of the push and the pull models may remove some previous concerns The individual grid resources may decide when more work can be taken and send a request for work to a grid job server New work is then sent by the job server Failover conditions need to be c
173. cred GSSCredential DEFAULT LIFETIME Chapter 6 Programming examples for Globus using Java 137 Destroying the proxy As the proxy is actually a file destroying the proxy is quite simple The file can just be deleted Example 6 5 Destroying a proxy public void proxyDestroy File file null String proxyfile CoGProperties getDefault getProxyFile if proxyfile null return file new File proxyfile Util destroy file 6 3 GRAM The Java CoG Kit provides two packages to access the GRAM API and run Gram jobs gt org globus gram gt org globus gram internal The org globus gram internal package contains as the name indicates only internal classes that are used by the main org globus gram package The org globus gram package provides the GRAM client API Inside org globus gram the most important basic classes are gt GramuJob Class gt GramJobListener Interface gt GramException Exception 6 3 1 GramJob This class represents a GRAM job you can submit to a gatekeeper It also provides methods to cancel the job register and unregister a callback method and send signal commands 6 3 2 GramJobListener This interface is used to listen for a status change of a GRAM job 138 Enabling Applications for Grid Computing with Globus 6 3 3 GramException This class defines the exceptions thrown by a GRAM job GRAM example This example will submit a simple job to a known resource manager It s
174. creen with the unsuccessfulLogin html file See Figure 8 4 on page 219 218 Enabling Applications for Grid Computing with Globus login html Login Servlet Authenticated Access denied unsuccessful Login html welcome html Figure 8 4 Simple grid portal login flow Example 8 1 shows sample script code for the login html to display the sample login screen Tip The login servlet is associated with login html with the following statement FORM name form method post action Login gt Example 8 1 Sample login html script lt DOCTYPE HTML PUBLIC W3C DTD HTML 4 01 Transitional EN gt lt HTML gt lt HEAD gt META http equiv Content Type content text html charset IS0 8859 1 gt META name GENERATOR content IBM WebSphere Studio gt lt META http equiv Content Style Type content text css gt lt LINK href theme Master css rel stylesheet type text css gt lt TITLE gt 1ogin html lt TITLE gt lt HEAD gt lt BODY gt lt FORM name form method post action Login gt lt TABLE border 1 width 662 height 296 gt lt TBODY gt lt TR gt lt TD width 136 height 68 gt lt TD gt lt TD width 518 height 68 gt lt TD gt lt TR gt lt TR gt lt TD width 136 height 224 gt lt TD gt lt TD width 518 height 224 gt Chapter 8 Developing a portal 219 lt P gt Userid lt INPUT type text name userid size 20 maxlen
175. d 4 2 1 Shared file system Sharing data across the compute nodes may sometimes be mandatory or may appear as the simplest solution to permit a computation to be distributed When data are in plain files network file systems are a convenient solution The question is not to choose between staging the data in and out or using a shared Chapter 4 Data management considerations 85 file system but to find the appropriate data flow that will provide optimal performance Therefore a mixed solution can be considered For example a network file system could be shared across a cluster of compute nodes and input and output files would be staged in and out of the shared files system from a permanent storage center Globus Toolkit does not provide a shared file system but can be used with any available shared file system Therefore in 4 2 11 Global file system approach on page 90 we describe in detail some shared file system solutions available today or in the near future 4 2 2 Databases Data grids have generally focused on applications where data is stored in files However databases have a central role in data storage access organization authorization and so on for numerous applications Globus Toolkit 2 x provides no direct interface for relational or object databases such as DB2 Oracle and MySQL However a grid enabled application could certainly use any available API such as SQL to access these databases However there
176. d Parallelization Section 2 1 of Introduction to Grid Computing with Globus SG24 6895 provides certain thoughts about parallelization of jobs for grids For example when dealing with mathematical calculations the commutative and associative laws can be exploited In iterative scenarios for example convergent approximation calculations where the output of one job is required as input to the next job of the same kind a serial job flow is required to reach the desired result For best performance these kinds of processes might be executed on a single CPU or cluster though performance is not always the primary criteria Cost and other factors must also be considered and once a grid environment is constructed such a job may be more cost effective when run on a grid versus utilizing a dedicated cluster An application may consist of a large number of such calculations where the start parameters are taken from a discrete set of values Each resulting serial application flow then could be launched in parallel on a grid in order to utilize more resources The serial flow A through D in Figure 3 2 is then replicated to A through D A through D and so forth Figure 3 2 Serial job flow Enabling Applications for Grid Computing with Globus In case it is not possible to completely convert a serial application flow into a parallel one a networked application flow may result 3 2 3 Networked flow In this case perhaps the
177. d to the home directory of the user on the server machine server ez opts GLOBUS GASS SERVER EZ TILDE USER EXPAND get requests will be fullfilled server ez opts GLOBUS GASS SERVER EZ READ ENABLE put requests will be fullfilled server ez opts GLOBUS GASS SERVER EZ WRITE ENABLE for put requets on dev stdout will be redirected to the standard output stream of the gass server server ez opts GLOBUS GASS SERVER EZ STDOUT ENABLE for put requets on dev stderr will be redirected to the standard output stream of the gass server server ez opts GLOBUS GASS SERVER EZ STDERR ENABLE put requests to the URL https host dev globus gass client shutdown will cause the callback function to be called this allows the GASS client to communicate shutdown requests to the server server ez opts GLOBUS GASS SERVER EZ CLIENT SHUTDOWN ENABLE Secure char scheme https unsecure char scheme http globus gass transfer listenerattr t attr globus gass transfer listenerattr init amp attr scheme we want to listen on post 10000 globus gass transfer listenerattr set port amp attr 10000 Now we can start this gass server globus gass transfer listener t listener 356 Enabling Applications for Grid Computing with Globus globus gass transfer requestattr t regattr GLOBUS NULL purpose unknown int err globus gass server ez init amp listener amp attr scheme
178. data Chapter 8 Developing a portal 237 getstatus req getParameterValues status logout req getParameterValues logout Which application was selected appselect req getParameterValues appselect if run null amp amp run length gt 0 submitApplication submit job else if getresult null amp amp getresult length gt 0 getResult get run result else if getstatus null amp amp getstatus length gt 0 getStatus get job status else if logout null amp amp logout length gt 0 doLogout logout else invalidInput catch Throwable theException uncomment the following line when unexpected exceptions are occuring to aid in debugging the problem theException printStackTrace throw new ServletException theException private void submitApplication if appselect 0 equals weather submitWeather else if appselect 0 equals gene submitGene else if appselect 0 equals test submitTest else if appselect 0 equals demo submitDemo else invalidSelection private void submitWeather String title Submit weather application out printIn html out printIn head out printIn lt title gt title lt title gt out printIn lt head gt out println body bgcolor cfd09d text 000099 gt out println hl align center gt title lt h1 gt out printIn
179. datory to use get current dir name include lt unistd h gt include globus_common h include itso gram job h include itso gass copy h include lt iostream gt include lt fstream gt include itso_gass_server C include lt cc socket h gt include lt cstdlib gt ifdef CCXX NAMESPACES using namespace std using namespace ost endif static variables used by the FrontEndServer threads They are initialized at startup and readonly Note that for a real production case ticket will probably variable A locking mechanism with mutex needs to be used static char hostname MAXHOSTNAMELEN static long ticket Appendix B C C source code for examples 341 f E EFAAAAAARAAA AAA RA AAA AAA AA AAA AREA AA KEK KK EKER RK KER KEKE RK KEE RK We use here the GNU Common C classes to implement the basic server that will listen onb port 4096 to manages client request and redirects them on the application server The Server class is derived from TCPSocket class Each client Session object Thread is from class TCPSession The member run is executed for each acceped connection and http www gnu org software commonct docs refman html classes htm for details BRERA RRR RRR RR eke ER ERE RR KK RRR KKK ERR EKER KK ERE KEKE KER KERR KR ERK BRRRR RRR RRR AAA AAA AAA AA ARA KKK ERR KEKE KEKE KEKE ERK RE RK KERR class GridApp public TCPSocket
180. de amp io attr GLOBUS IO SECURE AUTHENTICATION MODE GSSAPI credential handle globus io attr set secure authorization mode amp io attr GLOBUS IO SECURE AUTHORIZATION MODE SELF amp auth data We want encrypted communication if not use GLOBUS IO SECURE CHANNEL MODE CLEAR globus io attr set secure channel mode amp io attr GLOBUS IO SECURE CHANNEL MODE GSI WRAP globus io attr set secure protection mode amp io attr GLOBUS IO SECURE PROTECTION MODE PRIVATE encryption will see later for the delegation globus io attr set secure delegation mode amp io attr GLOBUS IO SECURE DELEGATION MODE FULL PROXY globus io attr set secure proxy mode amp io attr GLOBUS IO SECURE PROXY MODE MANY unsigned short port 10000 globus io handle t handle globus io tcp create listener Chapter 7 Using Globus Toolkit for data management 177 amp port zis amp io_attr amp handle _ globus_io_tcp_listen amp handle globus io handle t newhandle globus io tcp accept amp handle GLOBUS NULL amp newhandle globus size t n char buf 500 globus io read amp newhandle globus byte t buf 500 5 amp n cout buf n endl 7 3 Global access to secondary storage This section provides examples of using the GASS API 7 3 1 Easy file transfer by using globus gass copy API The Globus GASS Copy library is motivated by the desire to provide a uniform interface to transfer
181. de function allows the caller to find out which protocol will be used for a given URL globus url parse determines the validity of a URL Chapter 7 Using Globus Toolkit for data management 179 Note The GASS Transfer API is defined in the header file globus_gass_copy h and GLOBUS_GASS_COPY_MODULE must be activated before calling any functions in this API GAS Copy example The best example is the globus url copy c source code provided in the Globus Toolkit 2 2 It is strongly advised to have a look at this source code to understand how to use Globus Toolkit GASS calls This example shows how to copy a local file remotely via a GASS server A GASS server needs to be started on the remote location Note that this example is incomplete in the sense that it does not check any error codes returning from the Globus calls Consequently any malformed URL can cause the program to hang or fail miserably mO itso maya com t2 itso tupi com P TERE SEN tmp TEST home globus OO register Globus take care of file transfer synchonize LA With callback calls Figure 7 4 GASS Copy example h GASS server Example 7 14 gasscopy C include globus_common h include globus_gass_copy h include lt cstdlib gt include lt cstdio gt include lt iostream gt include lt cstring gt 180 Enabling Applications for Grid Computing with Globus BRR RRR RRR RRR
182. de host name The process ID of the SubmitGlobus script could be used to add more granularity and avoid conflicts between jobs submitted from the same host and from different users or with different parameters If one good result is found the stdout output is redirected locally from the execution node to the submission node and will appear during the execution GenerateDrawsGlobus generates random draws It is slightly different from the previous GenerateDraws program in that it writes the Monitor file under a different file name Monitor submission node hostname filename Monitor filename append argv 1 OutputFileMonitor open filename c_str The lt submission node hostname gt is actually passed as a parameter see GenerateDrawsGlobus C on page 352 by the GenerateDrawsGlobus sh that itself receives these parameters from the RSL command In the SubmitGlobus script executable GenerateDraws sh arguments TMP n param In GenerateDraws sh script GenerateDrawsGlobus 1 1 2 grep 3 amp amp echo GOT IT on HOSTNAME For a job submitted from mO itso maya com to t1 itso tupi com the RSL string is amp resourceManagerContact cl itso cherokee com executable GLOBUSRUN GASS URL home globus JYCode other GenerateDrawsGlobus sh arguments m0 itso maya com 300000 2 3 6 7 8 20 45 55 subjobStartType loose barrier file stage in GLOBUSRUN GASS URL home globus JYCode other GenerateDrawsGl
183. ded in the search result attrs 0 GLOBUS NULL globus module activate GLOBUS GRAM CLIENT MODULE Open connection to LDAP server if Idap server 1dap open server port GLOBUS NULL ldap perror ldap server 1dap_open exit 1 Bind to LDAP server if ldap simple bind s ldap server Mam LDAP SUCCESS ldap perror ldap server dap simple bind s ldap unbind ldap server exit 1 do the search to find all the Linux available nodes string filter objectClass MdsComputer Mds 0s name Linux string filter amp Mds 0s name Linux Mds Host hn if ldap_search_s ldap_server base dn LDAP_SCOPE_SUBTREE const_cast lt char gt filter c_str attrs 0 amp reply LDAP SUCCESS ldap perror ldap server dap search ldap unbind ldap server exit 1 vector lt Host gt nodes go through the entries returned by the LDAP server for each entry we must search for the right attribute and then get the value associated with it for entry ldap first entry ldap server reply entry GLOBUS NULL entry ldap next entry ldap server entry cout lt lt end lt lt 1dap get dn ldap_server entry lt lt endl Appendix B C C source code for examples 329 BerElement ber char values char attr char answer GLOBUS NULL string hostname int cpu int cpu nb long speed for attr ldap first attribut
184. e 160 Enabling Applications for Grid Computing with Globus GASSInteractive run new GASSInteractive run startGassServer run runJob System out print n All Done Deactivator deactivateAl1 6 8 Summary In this chapter we have provided several programming examples of using the Java CoG to access the various services provided by the Globus Toolkit By using these examples and the sample code provided with the Java CoG readers can gain an understanding of the various Java classes provided by the CoG and start utilizing them to create their own applications Chapter 6 Programming examples for Globus using Java 161 162 Enabling Applications for Grid Computing with Globus Using Globus Toolkit for data management There are two major components for data management in the Globus Toolkit gt Data transfer and access gt Data replication and management For basic data transfer and access the toolkit provides the Globus Access to Secondary Storage GASS module which allows applications to access remote data by specifying a URL For high performance and third party data transfer and access Globus Toolkit Version 2 implements the GridFTP protocol This protocol is based on the IETF FTP protocol and adds extensions for partial file transfer striped parallel file segment transfer TCP buffer control progress monitoring and extended restart Copyright IBM Corp 2003 All rights reserved 163 Globus
185. e arguments System out println After removing the argument myrsIstring3 your rs string is System out println Your rs string is attribs toRSL System out printIn Example 6 13 removes globusproject from the RSL string amp executable bin echo arguments globusproject The remove method finds the attribute in the string and removes the value globusproject The remaining string is printed to the screen Example 6 14 RSL example 3 of 6 add attributes System out println Your rs string is attribs toRSL attribs add myrslstring4 myrs lstring5 result attribs getSingle arguments System out print In After adding the arguement result your rs string is System out print ln attribs toRSL System out printIn Example 6 14 adds a value of www globus org to the attribute argument The add method finds the attribute and adds the value www globus org Example 6 15 RSL example 4 of 6 uses rs substitution attribs new RslAttributes myrslstring2 System out println Your rs string is attribs toRSL rslsubvars attribs getVariables rs substitution if rslsubvars containsKey EXECDIR rslsubvars get EXECDIR result attribs getSingle executable System out print n Your executable is result System out printIn 146 Enabling Applications for Grid Computing with Globus Example 6 15 on page 146 uses rsl_su
186. e 6 19 GridFTP basic third party transfer 2 of 4 Load credentials from proxy file private void getCredentials throws Exception GlobusCredential gcred new GlobusCredential tmp x509up_u1101 System out println GCRED gcred toString Chapter 6 Programming examples for Globus using Java 149 cred new GlobusGSSCredentialImpl gcred GSSCredential DEFAULT LIFETIME When creating the GridFTPClient it is important to use the GridFTP port which defaults to 2811 Authentication is done using the authenticate method passing the GSSCredentials It is important to authenticate to the GridFTPClient first before setting or changing any other properties like transfer type or mode Setting the client manually to active or passive is possible but not required for third party transfers Example 6 20 GridFTP basic third party transfer 3 of 4 Initializing the FTPClient on the source server private void initSourceClient throws Exception sClient new GridFTPClient tl itso tupi com 2811 sClient authenticate cred authenticating sClient setProtectionBufferSize 16384 buffersize sClient setType GridFTPSession TYPE IMAGE transfertype sClient setMode GridFTPSession MODE EBLOCK transfermode sClient setDataChannelAuthentication DataChannelAuthentication SELF sClient setDataChannelProtection GridFTPSession PROTECTION SAFE Initializing the FTPClient on the destination server private void
187. e Ske ke e ke he ke Ske e ke Ske e ke Ske e He ke e He He e He Ae H He Ae Ske ke Ke Ske ke static void globus_l_url_copy_monitor_callback void callback_arg globus_gass_copy_handle_t handle globus_object_t error MONITOR monitor globus_bool_t use_err GLOBUS_FALSE monitor MONITOR callback_arg if error GLOBUS_SUCCESS cerr lt lt url copy error lt lt globus object printable to string error lt lt end moni tor setError error moni tor setDone return globus url copy monitor callback f BRERRRRR RRR RR RR ER ER ERR KK ERK KKK KR KR KK ERK KK EK EKER ERR KK ERK EKER KR ERK EERE This Class implements the transfer from one local file to a GASS url http https The class ITSO_GASS TRANSFER implements a more cmoplete set of transfer source or destination can be either file 184 Enabling Applications for Grid Computing with Globus http https or gsiftp See appendix 2 for its source or HelloWorld example for an example how to use it To use it you must call setDestination to register your destination url setBinaryMode wraps the globus gass transfer requestattr set file mode and is an example how to set up options that applies to the kind of transfer These options are specific to the protocol startTransfer wraps the call to globus gass copy register handle to url that registers the asynchronous copy operation in the Globus API The monitor object that m
188. e a proxy from an application the JavaCoG Kit must be installed and configured The proper configuration will provide correct paths to the necessary files in the cog properties file The toolkit provides an easy way to read the cog properties file 134 Enabling Applications for Grid Computing with Globus Important The JavaCoG 1 1a provides support to both GT3 and GT2 2 proxies By default it will create a GT3 proxy In order to create a GT2 2 proxy the proxyType field must be set properly Creating a proxy This is a basic programming example that shows how to create a proxy compatible with the Globus Toolkit V2 2 The CoGProperties class provides an easy way to access the cog properties file where all file locations are stored Example 6 1 Creating a proxy 1 of 3 import java io File import java io FileOutputStream import java io IOException import java io QutputStream import java security PrivateKey import java security cert X509Certificate import org globus common CoGProperties import org globus gsi CertUtil import org globus gsi GSIConstants import org globus gsi GlobusCredential import org globus gsi OpenSSLKey import org globus gsi bc BouncyCastleCertProcessingFactory import org globus gsi bc BouncyCastle0penSSLKey import org globus gsi proxy ext ProxyCertInfo import org globus util Util GridProxy Used to create a proxy x public class GridProxy X509Certificate
189. e available with Globus Toolkit V3 Again this is early information and may change before general availability It is presented here to provide the reader with a flavor of what the services in Globus Toolkit V3 will look like 10 4 1 Index Services Index Services is like the MDS feature in GT2 It provides information about the grid services in XML format Unlike GT2 there is no need for a GRIS because each service has a set of information associated with itself This information is stored in a standard way making it easy to retrieve and understand the service data Each service is required to report common service data and any additional data is optional allowing users to get a standard set of information from any grid service 10 4 2 Service data browser This allows users to view the details of the grid services available and the Web Server Description Language of those services within a GUI 10 4 3 GRAM With the Globus Toolkit V3 users will submit jobs by the way of Web services The GRAM architecture will be rendered by OGSA via five services The Master Managed Job Factory Service MMJFS that is responsible for exposing the virtual GRAM service to the outside world The Master uses the Service Data Aggregator to collect and populate local Service Data Elements which represent local scheduler data freenodes totalnodes and general host information host cpu type host OS The Managed Job Factory Service MJFS that
190. e game is available in SmallBlue C standalone version on page 331 The algorithm as well as the GAME class is not studied in the publication The GAME class provides methods to display the Enabling Applications for Grid Computing with Globus game to check if someone has won to play the position decided by the players and to test if a player can play a specific column 4 5 6 7 8 position 1 ZZZZ position 2 position 3 position 4 i white 2 position 5 Uscio ia position 6 position 7 position 8 Figure 9 3 Problem suitable for Grid enablement In the extract of the SmallBlue C Example 9 9 on page 264 source code we can see that The evaluation of a position is performed via the Simulate function called from the main program The SmallBlue application uses the object Current of type GAME to store the game data This data is used to perform the evaluation of a position The evaluation of a position is performed in the function Simulate that takes two parameters The tested position and the game data Simulate returns the value of the evaluation This function is called for each column in main The Value method of the GAME class is used to evaluate the value of a position It takes the tested column as a parameter as well as the player BLACK WHITE who is playing the column This method is called in Simulate Chapter 9 Application examples 2
191. e job s executable and its ability to be moved across the network When developing grid enabled applications you may not know anything about the topology of the grid on which they will run However especially in the case of an intra grid that may be put in place to support a specific set of applications this information may be available to you In such a case you may want to structure 56 Enabling Applications for Grid Computing with Globus your application and grid in such a way as to optimize the environment by considering the location of the resources the data and the set of nodes that a particular application might run on 3 8 Passing of data input output As defined earlier any job in the grid application needs to pass data in and out in the sense of a data producer and a data consumer There are various ways to realize the passing of data input and output that are to be considered during application architecture and design Command line interface CLI can be a natural way for batch jobs and standard applications to receive data In this case the data input normally will not be complex in nature but consists of certain arguments used as parameters to control the internal flow of the job Such CLIs can easily be integrated in scripts executed at the system level or within a given interpreter The transfer of data to the job as a consumer happens immediately at launch time The amount of data will normally be small For larger amo
192. e ldap server entry amp ber attr NULL attr ldap next attribute ldap server entry ber values ldap get values ldap server entry attr answer strdup values 0 ldap value free values if strcmp Mds Host hn attr 0 hostname answer if strcmp Mds Cpu Free 15minX100 attr 0 cpuzatoi answer if strcmp Mds Cpu Total count attr 0 cpu nbzatoi answer if strcmp Mds Cpu speedMHz attr 0 speed atoi answer printf s s n attr answer check if we can really use this node if globus_gram_client_ping hostname c_str nodes push back new Host hostname speed cpu_nb cpu 100 h sort nodes begin nodes end predica vector lt Host gt iterator i for i nodes begin n gt 0 amp amp i nodes end n i res push_back i gt getHostname cout lt lt i gt getHostname lt lt lt lt i gt getCpu lt lt end delete i for i nodes end i delete i ldap unbind ldap server globus module deactivate GLOBUS GRAM CLIENT MODULE get ldap attribute 330 Enabling Applications for Grid Computing with Globus SmallBlue example This is a sample game playing program SmallBlue C standalone version include string include lt iostream gt include lt fstream gt using namespace std include GAME C int Simulate GAME newgame int col int 1 0 s int start newgame Value col WHI
193. e of use and a graphical user interface via the grid portal If the architectures of the grid resources are heterogeneous in nature the solution should provide automation to hide these complexities and provide tools for compiling applications for multiple execution environments This could also be considered under portability requirements typically addressed under the non functional requirements gt Ease of user and host access control should be provided from a single source with appropriate security mechanisms 60 Enabling Applications for Grid Computing with Globus Informative and predictable aspects Status of the grid must be readily available to continually show the status and operation of the grid This may include indicators showing grid load or utilization number of jobs running number of jobs queued but not yet dispatched status of hosts available resources reserved resources and perhaps highlighting bottlenecks or trouble spots Since the makeup of the grid may be changing dynamically predicting response times becomes harder The appropriate trade offs should be discussed to establish acceptable requirements with associated costs based on the needs of the business Resilience and reliability Some aspects for resilience and reliability of the grid application have already been covered In this section it is highlighted from the grid user perspective gt Particular attention must be paid to the requirements for handlin
194. eady held the program until the job completed we can now dispose Appendix B C C source code for examples 361 of it We destroy both the mutex and the condition This frees up any space it may have occupied xj globus mutex destroy 8Monitor mutex globus cond destroy 8Monitor cond Free up the resources of the job contact as the job is over and the contact is now useless xf globus gram client job contact free job contact Deactivate GRAM globus module deactivate GLOBUS GRAM CLIENT MODULE FERRARA AAARA RARA eke ke e he ke e he ke e he he AAA AAA ERK ERK EKER EKER ERE KE RRR KERR KER This is the callback function as per the definition We can write whatever we want into the function but remember that the cond_signal must be triggered and Monitor done must also be set to true to exit the waiting loop in the main code The function is called from the job manager which provides values for state and errorcode void callback func void user callback arg char job contact int state int errorcode my monitor t Monitor my monitor t user callback arg switch state case GLOBUS GRAM PROTOCOL JOB STATE PENDING printf tTEST Got GLOBUS GRAM PROTOCOL JOB STATE PENDING from job manager n break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE ACTIVE printf tTEST Got GLOBUS GRAM PROTOCOL JOB STATE ACTIVE from job manager
195. eb site 372 Contactus xvi reliability 37 reliable data transfer 26 Reliable File Transfer Service 296 Replica Catalog 96 Replica Location Service 97 296 replica management 28 208 replica management installation 211 replication 86 resource management 5 10 14 17 considerations 22 resources grid wide 24 local 24 RSL 18 113 120 134 139 145 165 example Java 145 for data management 165 runtime considerations 40 runtime environment 55 S SAL 63 sandbox 89 250 scavenging grids 4 scheduler 9 21 29 considerations 30 secure communication 16 376 Enabling Applications for Grid Computing with Globus Secure Socket Layer 16 security 5 7 14 considerations 17 serial flow 46 47 service data browser 293 service provider license agreement 63 service providers 63 servlet 218 shared data access 74 signal management 106 single sign on 14 17 Small Blue example 262 331 SOAP 6 58 SOAP message security 290 software license 62 Spitfire 100 SRB 101 SSL TSL 16 StartGASSServer example 324 StopGASSServer example 324 Storage Area Networks 26 Storage Resource Broker 100 storage servers 26 Storage Tank 94 stream mode 202 striped data transfer 26 subjobs 22 50 submitting a Job 110 Subscriber Access Licenses 63 system management 38 system return value 57 T temporary data spaces 76 third party file transfer 26 149 thread life cycle management 106 thread safety 109 time sensitive data 77
196. ecent activities on Application Development Environments ADEs for grids at Globus refer to http ww globus org research development environments htm Examples of using the Java CoG for grid application development are given in Chapter 6 Programming examples for Globus using Java on page 133 Grid enabled Message Passing Interface MPI A grid enabled Message Passing Interface that fits with the Globus Toolkit is provided by MPICH G2 This implementation of the MPI standard allows the 66 Enabling Applications for Grid Computing with Globus coupling of multiple machines and provides automatic conversions of messages It addresses solutions that are distributed by nature as well those distributed by design For details and the latest updates see http www niu edu mpi Grid Application Development Software GrADS An example for a distributed by design scenario is given by the Grid Application Development Software project The goal of this approach sponsored by the US Department of Energy DoE is to simplify distributed heterogeneous computing in the same way that the World Wide Web WWW simplified information sharing over the Internet GrADS has been developed for various Unix versions Solaris HP UX Linux It is written in C C and exploits LDAP Several software projects are built on top of it including a Common Component Architecture CCA and XCAT The GrADS project explores the scientific and technical problems t
197. ecution machine Tip It is a good idea to periodically clean up the cache Globus does not clean up the cached output files It will be a good idea to set up a routine administrative procedure to periodically clean up the cache with the command rm globus gass cache in the globus gass cache directory on the execution machine Repository of job ids for submitted applications Example 8 10 on page 236 shows a class that could be used as a container for job IDs for all submitted applications Chapter 8 Developing a portal 235 Example 8 10 Container for submitted job IDs import java util public class JSPBean private ArrayList jobIds public JSPBean jobIds new ArrayList public void addJobId String id jobIds add id public String getJobIds return String jobIds toArray new String 0 8 2 2 Putting it together Example 8 11 includes the complete source code for the portal as has been described throughout this chapter Example 8 11 Complete source code for grid portal sample package com ibm itso mygridportal web ir ir ir ir ir ir ir ir port port port port port port port port version 1 0 author public class Application extends HttpServlet java io IOException javax servlet javax servlet ServletException javax servlet http HttpServlet javax servlet http HttpServletRequest javax servlet http HttpServletResponse
198. ed backed up managed and or replicated Within a grid design you want to make sure that your data is always available to the resources that need it Besides availability you want to make sure that your data is properly secured as you would not want unauthorized access to sensitive data Lastly you want more than decent performance for access to your data Obviously some of this relies on the bandwidth and distance to the data but you will not want any I O problems to slow down your grid applications For applications that are more disk intensive or for a data grid more emphasis can be placed on storage resources such as those providing higher capacity redundancy or fault tolerance 2 2 4 Mixed platform environments A grid environment is a collection of heterogeneous hosts with various operating systems and software stacks To execute an application the grid infrastructure needs to know the application s prerequisites to find the matching grid host environment Below are some things that the grid infrastructure must be aware of to ensure that applications can execute properly It is equally as important for the application developer to consider these factors in order to maximize the kinds and numbers of environments on which the application will be able to execute Runtime considerations The application s runtime requirements and the grid host s runtime environments must match As an example below are some considerations for Java a
199. ed code cond_wait becomes globus_poll and it sits in a loop using CPU to wait for the callback In a threaded build cond_wait would put the thread to sleep F E He RRA e e e e KK e he e Ae ERK KK EK KK Ae e He Ae e He Ae KER KR ERK She e He ke KEKE KEKE KKK e e e e e e Kk ERE globus mutex lock amp lock while done globus mutex unlock amp lock globus cond wait amp cond amp lock ERROR AR RARA AAA AAA AAA A KR ERK ERK KR ERE AAA AAA AA AAA AREA AA RA RAR AAA ARA AIA AAA Since done has been set to true the done callback has been called The transfer is now completely finished both control channel and data channel Now Clean up and go home RAK KR KKK RA KKK RAK ERK EKER KK ERK AAA KARA RARA KR ERK ERK EKER ARA AAA RA RAR e kk kkk Chapter 7 Using Globus Toolkit for data management 207 globus ftp client handle destroy amp handle globus module deactivate all return 0 To compile the program gcc I usr local globus include gcc32 L usr local globus lib o gridftpclient2 gridftpclient2 c lglobus ftp client gcc32 To use it globus m0 globus grid proxy init Your identity O Grid 0O Globus OU itso maya com CN globus Enter GRID pass phrase for this identity Creating proxy adele lia este eleme e ere ie m pi ern E ere Done Your proxy is valid until Thu Mar 6 02 17 53 2003 globus m0 globus gridftpclient2 LocalFile gsiftp g2 tmp RemoteFile Shells tools
200. ed by the Globus Project and Work Package 2 of the European DataGrid project RLS is intended to eventually replace the Globus Toolkit s Replica Catalog component For more information see http www globus org rls http ww isi edu annc RLS htm Grid Data Mirroring Package GDMP The GDMP is client server software developed in C and built on top of the Globus Toolkit 2 framework Every request to a GDMP server is authenticated by the Globus Security Infrastructure It provides two things gt ageneric file replication tool to replicate files from one site to one or more remote sites A storage location is considered to be a disk space on a single machine or several machines connected via a local area network and a network file system gt GDMP manages Replica Catalog entries for file replicas and therefore makes the file visible to the grid Registration of user data into the Replica Catalog is also possible via the Globus Replica Catalog C C API The concept is that data producer sites publish their set of newly created files to a set of one or more consumer sites The consumers will then be notified of new files entered in the catalog of the subscribed server and can make copies of required files automatically updating the Replica Catalog if necessary Note 1 Files managed by GDMP should be considered as read only by the consumer Note 2 GDMP is not restricted to disk to disk file operation It can deal with files permanentl
201. elnet program works fine for remote access the transmission of the data is in clear text That means that the data transmission would be vulnerable to someone listening or sniffing the data on the network While this vulnerability is low it does exist and needs to be dealt with To secure the remote communication between a client and grid server the use of Secure Shell SSH can be used SSH will establish an encrypted session between your client and the grid server Using a tool such as the GSI Enabled OpenSSH you get the benefits of the secure shell while also using the authentication mechanism already in place with GSI 16 Enabling Applications for Grid Computing with Globus Application enablement considerations Security When designing grid enabled applications security concerns must be taken into consideration The following list provides a summary of some of these considerations Single sign on ID mapping across systems GSI provides the authentication authorization and secure communications as described above However the application designer needs to fully understand the security administration and implications For instance ls it acceptable to have multiple users mapped to the same user ID on a target system Must special auditing be in place to understand who actually launched the application The application should be independent of the fact that different user ID mappings may be used across the diff
202. else 6 1 3 1 Portal User interface 6 1 3 2 SecUrlty used eam s eden diee mer die pads es 7 1 3 3 Broker oiran aer ao ERR ER A 8 1 3 4 Scheduler gcc tates skr ee ES amu dv ARES REPRE 9 1 3 5 Data management eh 9 1 3 6 Job and resource management e eee eee eee 10 1 97 Otheric rese Se e nits teste xo Pe ACE do ORTU Fa 11 1 4 Job flow in a grid environment 11 1 5 Summalby ine ett t Cen Sitter Dae SOR er AU EDR nee EETA 11 Chapter 2 Grid infrastructure considerations 13 2 1 Grid infrastructure components 14 21 1 Security x euet d su dr e ma As i oae s 14 2 1 2 Resource management 17 2 1 3 Information services llle 22 2 1 4 Data management i 25 2135 Scheduler scene che A Veri simae e ay 29 21 6 Load balancing el RR eR ERI EE RE CU ER EX 31 DAI BTOKO T ut oer ARD otto Setanta a wey desee wpe An 33 2 1 8 Inter process communications IPC 33 21 9 Portal 15 E ri dentu sce C d Re nnd lira 34 2 2 Non functional requirements 35 Copyright IBM Corp 2003 All rights reserved iii iv 2 2 1 Performance llle rn 36 2 22 Reliability wir sc eed ce ees AER ee SE La SETTE 37 2 2 3 Topology considerationS 0 cee ee 38 2 2 4 Mixed platform environments 0 eee eee eee 40 2 9 SUMIMANY odo sen LA Late A labi c o nie Lei 41 Chapter 3 Application architecture considerations 43 3 1 Jobs and grid applica
203. em user authorization Avaki can also be tied into an existing network user authentication system like LDAP so that information does not need to be duplicated into a separate grid access control list For more information see http www avaki com 4 2 12 SAN approach Storage Area Networks SAN are well suited for high bandwidth storage access When transferring large blocks there is not much processing overhead on servers since data is broken into a few large segments Hence SAN is effective for large bursts of block data It can be used when very large files for example videos have to be manipulated and shared at a level of reliability that no ordinary network can support Chapter 4 Data management considerations 93 94 Storage Tank IBM provides a complete storage management solution in a heterogeneous distributed environment Storage Tank is designed to provide I O performance that is comparable to that of file systems built on bus attached high performance storage In addition it provides high availability increased scalability and centralized automated storage and data management Storage Tank uses Storage Area Network SAN technology that allows an enterprise to connect thousands of devices such as client and server machines and mass storage subsystems to a high performance network On a SAN heterogeneous clients can access large volumes of data directly from storage devices using high speed low latency connection
204. ept proxy certificates in either GT 2 2 or GT 3 0 proxy certificate formats The proxy certificate format has been updated to bring it into compliance with the latest proxy certificate draft specification in the Global Grid Forum This code allows GT 2 2 and 2 4 proxy certificates to be used to authenticate with GT 3 0 services offering a backwards compatible migration path from GT 2 2 to GT 3 0 10 1 4 SOAP GSI plugin for C C Web services The gSOAP C Web services platform is being extended to work with OGSA services and to provide a full interoperability between C C and Java Web services using GSI A GSI module is used by gSOAP to support the Globus Toolkit 3 security mechanism This module is tracking with the OGSI evolution and currently supports httpg binding as delegation for job submission The gSOAP plugin is available from the following Web site http sara unile it cafaro gsi plugin html The gSOAP toolkit provides a SOAP to C C language binding for the development of SOAP Web services and clients It is used in the C implementation of the Globus Toolkit 3 to implement the SOAP protocol The gSOAP stub and skeleton compiler for C and C was developed by Robert van Engelen of Florida State University See the following Web site for more information http gsoap2 sourceforge net 10 2 OGSI implementation Open Grid Service Infrastructure OGSI addresses detailed specifications of the interfaces that a service must impleme
205. er to the executable within the grid These questions refer to input as well as output data of the jobs within the grid application Data topology graph In order to answer these questions a graphical representation can help like the one in Figure 4 2 This data topology graph lists all available nodes on one axis and all the jobs of the application on the other axis All required data stores are then placed on the appropriate intersections Data Topology J5 J4 J3 J2 J1 Jobs Nodes N1 N2 N3 N4 N5 Figure 4 2 Data topology of a grid The example in Figure 4 2 reveals that job J2 has to access data of three different data sources which are located on different nodes in the network In this case it is necessary to check whether the data extract of each of the data sources A D and F that is needed for job J2 can be sent over the network to the node where job J2 is going to be executed 78 Enabling Applications for Grid Computing with Globus Depending on the nature of the data sources the essential data for job J2 may be extracted or replicated to be close to or on the job executing node In case the data cannot be separated and the data amount is large it is necessary to check whether the job can be split into individual jobs or sub jobs to be executed close to the data If this is not possible one might consider moving the data of A D and or F to a single node where job J2 can run The data t
206. erent resources in the grid gt Multi platform Though the GSI is based on open and standardized software that will run on multiple platforms the underlying security mechanisms of various platforms will not always be consistent For instance the security mechanisms for reading writing and execution on traditional Unix or Linux based systems is different than for a Microsoft Windows environment The application developer should take into account the possible platforms on which the application may execute gt Utilize GSI For any application specific function that might also require authentication or special authorization the application should be designed to utilize GSI in order to simplify development and the user s experience by maintaining the single sign on paradigm gt Data encryption Though GSI in conjunction with the data management facilities covered later provides secure communication and encryption of data across the network the application designer should also take into account what happens to the data after it has arrived at its destination For instance if sensitive data is passed to a resource to be processed by a job and is written to the local disk in anon encrypted format other users or applications may have access to that data 2 1 2 Resource management The grid resource manager is concerned with resource assignments as jobs are submitted It acts as an abstract interface to the heterogeneous resources of
207. erent servers g0 itso guarani com and t0 itso tupi com Three files are stored on g0 itso guarani com and two others are located on t0 itso tupi com The two locations host a GridFTP server Chapter 7 Using Globus Toolkit for data management 209 url gsiftp t0 nome globus storage z protocol gsiftp tupi location list of files file1 file2 file3 url gsiftp g0 home globus storage gt guarani location protocol gsiftp list of files file4 file5 itsoCollection gt ff mani ifs size 185802 FileList fil size 232802 E size 3284802 file 5 size 1838602 size 187812 tupiFiles guaraniFiles filet file4 xd files file3 Figure 7 5 Replica example The steps are 1 First set up the environment export GLOBUS _REPLICA_CATALOG_HOST 1dap m0 itso maya com 1c itso Collection rc test dc itso maya dc com export GLOBUS REPLICA CATALOG MANAGER cn Manager dc itso maya dc com echo gt password 2 Create the three file lists One for the files in the collection one for the files located in gO itso guarani com and the last for the files stored on t0 itso tupi com for i in filel file2 file3 file4 file5 do echo i gt gt FileList done for i in filel file2 file3 do echo i gt gt tupiFiles done for i in file4 file5 do echo i
208. ery Service MDS Data management is concerned with how jobs transfer data or access shared storage Let us look at each of these components in more detail 2 1 1 Security Security is an important component in the grid computing environment If you are a user running jobs on a remote system you care that the remote system is secure to ensure that others do not gain access to your data If you are a resource provider that allows jobs to be executed on your systems you must be confident that those jobs cannot corrupt interfere with or access other private data on your system Aside from these two perspectives the grid environment is subject to any and all other security concerns that exist in distributed computing environments The Globus Toolkit at its base has the Grid Security Infrastructure GSI which provides many facilities to help manage the security requirements of the grid environment 14 Enabling Applications for Grid Computing with Globus As you are developing applications targeted for a grid environment you will want to keep security in mind and utilize the facilities provided by GSI The security functions within the grid architecture are responsible for the authentication authorization and secure communication between grid resources Grid security infrastructure GSI Let us see how GSI provides authentication authorization and secure communications Authentication GSI contains the infrastructu
209. et gass call that specifies that we are using the GASS protocol for the transfer This handle is also used by the gass transfer API to determine protocol properties In the example we specify binary transfer by calling globus gass transfer requestattr set file moder All these handlers need to be initialized before by using a globus gass copy init call specific to each handler The Globus Toolkit 2 2 provides the following functions to submit asynchronous transfers from an application gt globus gass copy register handle to url to copy a local file to a remote location globus gass copy register url to handle to copy a remote file locally gt globus gass copy register url to url to copy a remote file to a remote location This function uses a callback function that will be called when the transfer has been completed The prototype of this function is defined by globus gass copy callback ttype A synchronization mechanism like condition variables must be used by the calling thread to be aware of the completion of the transfer See Example 7 4 on page 180 Globus Toolkit 2 2 provides blocking calls that are equivalent to those listed above gt globus gass copy handle to url to copy a local file to a remote location gt globus gass copy url to handle to copy a remote file locally gt globus gass copy url to url to copy a remote file to a remote location The globus gass copy url mo
210. eted vector ITSO GLOBUS FTP CLIENT transfer never forget to activate the Globus module you want to use globus module activate GLOBUS FTP CLIENT MODULE 8 transfer let create 8 locks string dst for i 0 i 8 i cout lt lt node i lt lt endl dst gsiftp node i Smal1BlueSlave transfer push_back new ITSO_GLOBUS_FTP_CLIENT Smal1BlueSlave const_cast lt char gt dst c_str E Appendix B C C source code for examples 333 Let s begin the transfer in parallel in asynchronous mode for i 0 i 8 i transfer i gt StartTransfer Let wait for the end of all of them for i 0 i 8 1 transfer i gt Wait globus module deactivate GLOBUS FTP CLIENT MODULE h get the hostname using the globus shell function instead of POSIX system calls char hostname MAXHOSTNAMELEN globus libc gethostname hostname MAXHOSTNAMELEN used to store the RSL commands string rs req Start the GRAM callback server ITSO GRAM JOBS CALLBACK callback server create all the jobs objects that will be used to submit the requests to the nodes We use a vector to store them vector ITSO GRAM JOB job for i 0 i 8 i job push back new ITSO GRAM JOB amp callback server h By using gridftp SmallBlueSlave is copied onto the rmeote hosts as a plain file needs to chmod x to make it executable otherwise the job submission will fail cout chmod x on the remote hosts
211. existing infrastructure Chapter 4 Data management considerations 103 There are several existing and evolving technologies that can be used to manage and access data in a grid environment and we have described a few projects that have built tools on top of Globus to provide the required capabilities for data oriented grids 104 Enabling Applications for Grid Computing with Globus Getting started with development in C C In this chapter we will start looking at how these components are actually used both through the command line and through programs written to the Globus APIs Since the Globus Toolkit ships with C bindings we start out by providing some information for C C programmers that will help them better understand the programming environment We then provide some C C examples of calling Globus APIs The examples we use are based on the GRAM module for submitting jobs and the MDS modules for finding resources Copyright IBM Corp 2003 All rights reserved 105 5 1 Overview of programming environment In the next three subsections we provide information about programming and building C C applications that utilize the Globus Toolkit For more details and a list of all of the available APIs please visit the Globus Web site 5 1 1 Globus libc APIs The Globus Toolkit 2 2 is a cross platform development framework and allows the application development of portable grid applications by using its API The globus l
212. f on the data channel does not mean the control channel protocol exchange is complete This is indicated by the done callback being called KAKKKKKKK KAKA RK KKK KK EK ERK KK KKK KER KKK KKK e e KERR ERE EERE REKE re fread buffer 1 MAX BUFFER SIZE fd globus ftp client register write amp handle buffer rc 0 feof fd SUCCESS data_cb void fd EEE EK e H ke e e e ke de e eke ke eke e ke eke RR KR ERK EKER ERK KK RR KK ERK e ke Ske e He She e He He e KER ER Ke He He Ke He Ke ke e The CPU put following is a standard thread construct The while loop is required because pthreads may wake up arbitrarily In non threaded code cond wait becomes globus poll and it sits in a loop using to wait for the callback In a threaded build cond wait would the thread to sleep KAKKKAKAKKAKKAKAKAKARAAAAKA KARA AAA RK KR KK EERE KEKE KEKE KKK ERK KERR ERE globus mutex lock amp lock while done globus cond wait amp cond amp lock globus mutex unlock amp lock RARA AAA AAA AA AAA AIAR ARA RAR AAA RA AA AAA AA AAA RARA AAA RARA AAA AAA AIA RARA Since done has been set to true the done callback has been called The transfer is now completely finished both control channel and data channel Now Clean up and go home KKK RRA KKK KE KR KK RRR EKER KK EKER KARA RA KERR KER KK KEK EKER ER ERK REE RARA eke ke ke Ke f 200 Enabling Applications for Grid
213. f the script by using globus gass server shutdown as shown in Example 9 6 Example 9 6 Shutting down the remote GASS servers for i in 1oop do contact cat gass server i globus gass server shutdown contact done Monitoring globus ur1 copy is used to copy the Monitor files created by GenerateDrawsGlobus The Monitor files are not redirected to the submission node via GASS because GenerateDrawsGlobus keeps writing in the file and that would cause a lot of network traffic Example 9 7 Monitoring echo Monitoring rm f Monitor statussum 0 while statussum NodesNumber do echo sleep 5 we poll every 5 seconds statussum 0 258 Enabling Applications for Grid Computing with Globus for i in 1oop do if s gass server i then contact cat gass server i globus url copy contact Monitor TMP file PWD Monitor i status cat Monitor i statussum status statussum echo Nodes i Monitor cat Monitor i fi done statussum statussum 100 done Because the remote GASS server may not have started yet we check the size of the gass server i file If empty that means that no URL has been returned yet and therefore the GASS server has not yet started As in Example 9 7 on page 258 the for loop scans the content of each Monitor i copied from each execution host and displays them every five seconds Implementation Below we discuss the implementation Example 9 8 SubmitGlobus scri
214. f which are not Reserving resources on the grid in advance is accomplished with a reservation system It is more than a scheduler It is first a calendar based system for reserving resources for specific time periods and preventing any others from Chapter 2 Grid infrastructure considerations 29 reserving the same resource at the same time It also must be able to remove or suspend jobs that may be running on any machine or resource when the reservation period is reached Condor G The Condor software consists of two parts a resource management part and a job management part The resource management part keeps track of machine availability for running the jobs and tries to best utilize them The job management part submits new jobs to the system or put jobs on hold keeps track of the jobs and provides information about the job queue and completed jobs The machine with the resource management part is referred to as the execution machine The machine with the job submission part installed is referred to as the submit machine Each machine may have one or both parts Condor G provides the job management part of Condor It uses the Globus Toolkit to start the jobs on the remote machine instead of the Condor protocols The benefits of using Condor G include the ability to submit many jobs at the same time into a queue and to monitor the life cycle of the submitted jobs with a built in user interface Condor G provides notification of job com
215. function activates and deactivates the Globus GRAM module The algorithm takes into account the CPU speed the number of processors and the CPU workload and returns the best nodes available Only Linux nodes are returned Broker h ifndef ITSO BROKER H define ITSO BROKER H gris search c include globus_common h LDAP stuff include lber h include ldap h include lt string gt include lt vector gt include lt list gt include lt algorithm gt note this should be the GIIS server but it could be the GRIS server if you are only talking to a local machine remember the port numbers are different define GRID_INFO_HOST m0 define GRID_INFO_PORT 2135 define GRID_INFO_BASEDN mds vo name maya o grid namespace itso_broker void GetLinuxNodes vector lt string gt amp res int n fendif Broker C gris search c include globus_common h include globus gram client h LDAP stuff Appendix B C C source code for examples 327 include lber h include ldap h include lt string gt include lt vector gt include lt algorithm gt note this should be the GIIS server but it could be the GRIS server if you are only talking to a local machine remember the port numbers are different define GRID_INFO_HOST m0 define GRID_INFO_PORT 2135 define GRID_INFO_BASEDN mds vo name maya o grid f RRR RRR
216. g Example 6 12 RSL example 1 of 6 mport org globus rsl import java util import java io import junit framework import junit extensions public class MyRSL public void MyRSL public static void main String args RslAttributes attribs Map rslsubvars String myrslstring amp executable bin echo arguments globusproject String myrslstring2 amp rsl_substitution EXECDIR bin executable EXECDIR echo arguments www globus org String myrslstring3 globusproject String myrslstring4 arguments String myrsIstring5 bin 1s try print attributes attribs new RslAttributes myrslstring System out println Your rs string is attribs toRSL String result attribs getSingle executable System out print ln Your executable is result result attribs getSingle arguments System out println Your argument is result System out println Chapter 6 Programming examples for Globus using Java 145 The variable myrslstring contains the RSL string The string is then stored as type RslAttributes The RslAttributes class allows parsing modifying and deleting values in the string The getSingle method returns the value of a specified attribute Example 6 13 RSL example 2 of 6 remove attributes System out println Your rs string is attribs toRSL attribs remove myrslstring4 myrslstring3 result attribs getSingl
217. g char job contact int state int errorcode ITSO GRAM JOB Monitor ITSO GRAM JOB user callback arg switch state case GLOBUS GRAM PROTOCOL JOB STATE STAGE IN cout Staging file in on job contact endl break case GLOBUS GRAM PROTOCOL JOB STATE STAGE OUT cout lt lt Staging file out on lt lt job contact lt lt end break case GLOBUS GRAM PROTOCOL JOB STATE PENDING break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE ACTIVE break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE FAILED cerr lt lt Job Failed on lt lt job contact lt lt endl Monitor gt SetFailed Monitor gt setDone break Reports state change to the user case GLOBUS GRAM PROTOCOL JOB STATE DONE cout Job Finished on job contact endl Monitor gt setDone break Reports state change to the user static void request callback void user callback arg globus gram protocol error t failure code const char job contact globus gram protocol job state t state globus gram protocol error t errorcode ITO GRAM JOB Request ITSO GRAM JOB user callback arg cout Contact on the server job contact endl Request SetRequestDone job contact ITSO GRAM JOB ITSO GRAM JOB E 322 Enabling Applications for Grid Computing with Globus ITSO GRAM JOB ITSO GRAM JOB
218. g failures Failures should be handled gracefully The nature of the application must be understood to identify the correct handling of failures and to provide automatic recovery restart where possible Appropriate user notification should be included recognizing that the actual user may not always be connected to the grid Consequently asynchronous mechanisms for feedback might need to be incorporated The nature of applications that are suitable to run on the grid may provide a level of tolerance to failure not typically found in traditional applications An example of this maybe in the scavenging scenario where the application as a whole may be able to tolerate failure of one or more sub jobs Since jobs are run on donor machines the application is subject to the availability of these machines which are typically outside the application s scope of control Consequently the application must tolerate not receiving results from jobs dispatched to these donor machines Applications must be fully integrated with systems management tools to report status and failures In addition requirements should be established for how this information will be made available to the end user indicating the status of their jobs gt Consideration may also be given to providing intermediate results to an end user when these can provide valid results 3 12 Non functional criteria There are several non functional requirements that influence grid a
219. g generated To reach this vision there must be standards for grid computing that will allow a secure and robust infrastructure to be built Standards such as the Open Grid Services Architecture OGSA and tools such as those provided by the Globus Toolkit provide the necessary framework Initially businesses will build their own infrastructures what we might call intra grids but over time these grids will become interconnected This interconnection will be made possible by standards such as OGSA and the analogy of grid computing to the power grid will become real 1 1 1 Types of grids Grid computing can be used in a variety of ways to address various kinds of application requirements Often grids are categorized by the type of solutions that they best address The three primary types of grids are summarized below Of course there are no hard boundaries between these grid types and often grids may be a combination of two or more of these But as you consider developing applications that may run in a grid environment the type of grid environment that you will be using will affect many of your decisions Computational A computational grid is focused on setting aside resources specifically for compute power In this type of grid most of the machines are high performance servers Chapter 1 Introduction 3 Scavenging A scavenging grid is most commonly used with large numbers of desktop machines Machines are scavenged for available
220. g globus ftp GridFTPSession import org globus gsi GlobusCredential import org globus gsi gssapi GlobusGSSCredential Imp1 import org ietf jgss GSSCredential import org globus ftp import java io GridFTPclient Treansfers a file from the client to the server public class GridFTPclient private GridFTPClient client null Grid FTP Client private GSSCredential cred null Credentials First we have to get the credentials from our proxy file Chapter 6 Programming examples for Globus using Java 151 Example 6 23 GridFTP client server example 2 of 6 Load credentials from proxy file public void getCredentials throws Exception GlobusCredential gcred new GlobusCredential tmp x509up u1101 System out println GCRED gcred toString cred new GlobusGSSCredentiallmpl gcred GSSCredential DEFAULT LIFETIME We create a GridFTPClient on the remote host authenticate and set the parameters Example 6 24 GridFTP client server example 3 of 6 Initializes the ftp client on given host public void createFTPClient String ftphost throws Exception client new GridFTPClient ftphost 2811 client authenticate cred authenticating client setProtectionBufferSize 16384 buffersize client setType GridFTPSession TYPE IMAGE transfertype client setMode GridFTPSession MODE EBLOCK transfermode client setDataChannelAuthentication DataChannelAuthentication SELF client
221. g with Globus To copy the file SmallBlue in parallel to each remote host we use the GridFTP protocol via the ITSO GLOBUS FTP CLIENT vector ITSO GLOBUS FTP CLIENT transfer globus module activate GLOBUS FTP CLIENT MODULE string dst for i 0 i 8 i cout lt lt node i lt lt endl dst gsiftp node i Smal1BlueSlave transfer push back new ITSO GLOBUS FTP CLIENT SmallBlueSlave const cast char dst c str bs for i 0 i 8 i transfer i gt StartTransfer for i 031 83 i transfer i gt Wait globus module deactivate GLOBUS FTP CLIENT MODULE We also need to make Smal1Blue executable on the remote hosts because the file copied by GridFTP is copied as a plain file and not as an executable for i 0 i 8 i rs req amp executable bin chmod count 1 arguments x SmallBlueSlave if job i Submit node i rs req exit 1 for i 0 i 8 i job i gt Wait Example 9 10 SmallBlue Gridfication Initialization SmallBlueMaster C main Start a GASS server locally that will listen on 10000 port all the results of the evualtion We will stop it at the end It cannot be defined as a standalone class because the static callback does not take any argument So it is impossible afterwards in the callback to refer to the object StartGASSServer 10000 1TSO GRAM CLIENT does not start the module lets do it if globus module activate GLOBUS GRA
222. game getData xsize ysize GAME int x int y xsize x ysize y h GAME free data data char calloc x y 1 h char getData return data int getxsize return xsize int getysize return ysize 338 Enabling Applications for Grid Computing with Globus void ToDisk string filename ofstream out filename c_str int j i for j 1 j lt ySize j for i l i lt xsize i out lt lt get i j lt lt out close E void FromDisk int j i valeur for j 1 j lt ysize j for i l1 i lt xsize i cin gt gt valeur set i j valeur J h void Inverse int i j for j 1 j lt ysize j for i l i lt xsize i if get i j WHITE set i j BLACK else if get i j BLACK set i j WHITE h void Display int j i cout lt lt endl lt lt end cout lt lt di cout lt lt end for j l j lt ysize j cout lt lt for i l i lt xsize i if get i j WHITE cout lt lt 0 else if get i j BLACK cout lt lt I else cout lt lt cout lt lt cout lt lt end h cout lt lt lt lt endl cout lt lt 12345678 h bool Play int col int who int j if getl col 0 Appendix B C C source code for examples 339 cout lt lt col exit 1 h for j ysizesget col j 0 j set col j who k GAME amp operator GAME amp G2 memcpy data G2 get
223. gass cache directory of the user under which the job is executed The GASS cache is Chapter 4 Data management considerations 89 transparently used during job invocation via GRAM Files specified in the RSL strings are put into the cache if they are referenced as URLs See globus gass cache on page 193 for a more complete description 4 2 10 Data brokering A storage broker may be used by applications to provide them with the appropriate storage resources lt must provide the following capabilities Searching for an appropriate data storage location This means querying the Replica Catalog for all physical locations and querying each physical location Matching the resources according to the application needs gt Accessing the data The Globus Toolkit 2 does not provide a storage broker engine However some implementations have been written that use GRIS GridFTP and the Replica Catalog available in the Globus Toolkit 2 2 4 2 11 Global file system approach A global file system can be easily integrated into a Grid solution based on the Globus Toolkit A global file system provides access to storage and any applications can use POSIX system calls to access files without the need of any grid specific APIs Several solutions exist today that will fit project expectations across various criteria Performance cost ease of deployment and so on However they should not be considered as the only alternative Global file s
224. ge test import org globus io urlcopy UrlCopy import org globus io urlcopy UrlCopyListener import org globus util GlobusURL import org globus gsi gssapi auth URLCopy Performs a copy based on the URLCopy package 1 public class URLCopy implements UrlCopyListener public void transfer int transferedBytes int totalBytes System out print ln Transferred transferedBytes of totalBytes Bytes public void transferCompleted System out print ln Transfer Complete public void transferError Exception e System out println Error e getMessage All we need to do is to assign the URLCopy object properties like DestinationUrl and SourceAuthorization If the transfer is a third party transfer then the flag must be set using ucopy setUseThirdPartyCopy true 154 Enabling Applications for Grid Computing with Globus Example 6 29 URLCopy example 2 of 2 public void ucopy try UrlCopy ucopy new UrlCopy GlobusURL durl new GlobusURL gsiftp t2 itso tupi com tmp urlcopy GlobusURL sur new GlobusURL gsiftp tl itso tupi com etc hosts Authorization srcAuth null Authorization dstAuth null dstAuth new IdentityAuthorization 0 Grid 0 Globus CN host t2 itso tupi com srcAuth new IdentityAuthorization 0 Grid 0 Globus CN host t1l itso tupi com ucopy addUr CopyListener this ucopy setDestinationUr durl ucopy setSourceUr sur1 ucop
225. gt globus job run gt globus job submit gt globusrun gt gsissh not really a Globus job submission command but provides a secure shell capability using the Globus GSI infrastructure All these functions use the Grid Security Infrastructure Therefore itis mandatory to always create a valid proxy before running these commands The proxy can be created with the grid proxy init command globus job run globus job run is the simplest way to run a job The syntax is globus job run hostname program arguments The program must refer to the absolute path of the program However by using the s option globus will automatically transfer the program to the host where it will be executed Example 5 3 globus job run example globus m0 globus echo echo Hello World gt MyProg chmod x MyProg globus m0 globus grid proxy init Your identity 0 Grid 0 Globus OU itso maya com CN m0user Enter GRID pass phrase for this identity CHEATING PROXY dace uisu icem on cer a Done Your proxy is valid until Tue Mar 18 05 23 49 2003 globus m0 globus globus job run t1 MyProg GRAM Job failed because the executable does not exist error code 5 globus m0 globus globus job run t1 s MyProg Hello World The delimiter can be used to submit a multi request query as shown in Example 5 4 Example 5 4 multi request query globus m0 globus echo echo Hello 1 from HOSTNAME gt MyProg chmod x MyProg globus m0 globu
226. gt s get the best one if s gt 1 f 1 5 store its value toplay k remember the column to play E h results close nothing in the file that means we cannot play so it is NULL if 1 100000 cout NULL endl break l3 AI plays here and checks if it won Current Play toplay WHITE if Current HasWon toplay WHITE Current Display break The slave code is small GAME C implements the game artificial intelligence The slave begins to read the serialized object from standard input actually mapped to GAME file on the master node Current FromDisk Then the slave only tests the eight positions that can be played by the adversary It writes the result of the evaluation to standard output The GASS server started by GRAM actually maps this standard output to the file eval on the submission node Example 9 12 SmallBlueSlave C include lt iostream gt using namespace std include GAME C main int arc char argv 274 Enabling Applications for Grid Computing with Globus GAME Current XSIZE YSIZE load the Current object from the disk this object was copied from the submission node Current FromDisk which column should we simulate int col atoi argv 1 int start Current Value col WHITE Current Play col WHITE int 1 0 s k for k 1 K XSIZE 1 k s Current Value k BLACK if s gt 1 1 s h start 1 send back the information to the
227. gth 20 gt lt P gt lt P gt Password lt INPUT type password name password size 20 maxlength 20 gt lt P gt lt INPUT type submit name loginOkay value Login gt lt TD gt lt TR gt lt TBODY gt lt TABLE gt lt FORM gt lt BODY gt lt HTML Example 8 2 shows sample Login java servlet code Tip The class definition clause extends HttpServlet distinguishes a servlet Another distinguishing mark of a servlet is the input parameters HttpServletRequest req HttpServletResponse res The arguments from the login html are passed to the Login java servlet through the HttpServletRequest req parameter When the authentication is successful the control is passed to wecome html using a redirect command rd forward request response Example 8 2 Sample Login java servlet code package com ibm itso mygridportal web import java io IOException import javax servlet ServletException import javax servlet import javax servlet http HttpServlet import javax servlet http HttpServletRequest import javax servlet http HttpServletResponse version 1 0 author public class Login extends HttpServlet see javax servlet http HttpServlet void javax servlet http HttpServletRequest javax servlet http HttpServletResponse public void doGet HttpServletRequest req HttpServletResponse resp throws ServletException IOException performTask req resp 220 Enabling Applications for
228. h Globus ITSO GRAM JOB job cout lt lt library compilation on lt lt node lt lt endl rsl req amp executable https rs req hostname rs req 20000 rs req get current dir name rs req Compile count 1 submit it to the GRAM cout lt lt rs req lt lt endl job Submit node rsl req job Wait f BRRR RRR RRR RR eke ER EKER RK EKER KKK RK KER KK EKER ERE KEKE RE RK KE ke e ke A ticket getTicket time IP address SLA ina real production case ticket random node getNodes SLA MDS Workload Application Type in a real production case node t0 ITSO GRAM JOB job2 cout lt lt start app server on lt lt node lt lt endl rsl_req amp executable https rs req hostname rs req 20000 rsl req get current dir name rsl req HelloServer environment LD LIBRARY PATH HOME tmp lib count 1 arguments char tmpstr 20 sprintf tmpstr Zld ticket rs req tmpstr rs req node rs req submit it to the GRAM cout lt lt rs req lt lt endl job2 Submit node rsl req job2 Wait Front End server startup We use the GNU CommonC classes to implement a very basic server See below for explanation and http www gnu org software commonct docs refman html classes htm for details GridAppSession tcp Appendix B C C source code f
229. hat occur when applying grid technology for real applications in everyday life Details on GrADS are found at http nhse2 cs rise edu grads IBM Grid Toolbox For grid application development with Globus the CoGs can be used with appropriate IDEs IBM research offers the IBM Grid Toolbox as a set of development tools for grid application development on AIX and Linux It supports most of the grid services GRAM GSI MDS GASS simple CA I O and so on as described in this publication Details and download of the IBM Grid Toolbox are available at http www alphaworks ibm com tech gridtoolbox Grid Application Framework for Java Another application development item recently offered by IBM research is the Grid Application Framework for Java GAF44J It abstracts the interface to the Globus Toolkit for Java programmers by introducing an abstraction layer on top of Globus Details and downloads are available at http ww alphaworks ibm com tech GAF4J Other tools When searching the Internet for grid application development one finds a large number of hits with most of them pointing to AD tool vendors who claim their tools as being ready for supporting grid application development Even so any comprehensive competitive analysis will not be up to date as it is published because the standards OGSA are still developing Grid computing evolves in Chapter 3 Application architecture considerations 67 various directions for d
230. hat software is needed to provide synchronization between the jobs Another way to process this case is to let each job generate individual output files and then to run a post processing program to merge all these output files into the final result A similar case is illustrated in Figure 4 6 on page 84 Here each job has its individual input data set which it can consume All jobs then produce output data to be stored in a common data set Like described above the synchronization of the output for the final result can be done through software designed for the task Chapter 4 Data management considerations 83 Figure 4 6 Jobs with individual input data writing output into one data store Hence thorough evaluation of the input and output data for jobs in the grid application is needed to properly qualify it Also one should weigh the available data tools such as federated databases a data joiner and related products in case the grid application to be builtbecomes more data oriented or the data to be used shows a complex structure 4 1 11 Encrypted data Data encryption is mentioned in this context in order to complete this section of this publication A rather in depth discussion of the topic is given in Introduction to Grid Computing with Globus SG24 6895 At the architecture and design stage of a grid application project it is important to cover the encryption issues that are required by
231. he server This API is used by the globusrun shell commands to embed a GASS server within it The example in gassserver C on page 355 implements a simple GASS server and is an example of how to use this simple API The class ITSO CB in ITSO CP on page 315 and the function callback c function are used to implement the callback mechanism invoked when a client wants to shut down the GASS server This mechanism is activated by setting the options GLOBUS GASS SERVER EZ CLIENT SHUTDOWN ENABLE when starting the GASS server The examples in StartGASSServer and StopGASSServer on page 324 provide two functions that wrap the Globus calls Example 7 15 Using ITSO CB class as a callback for globus gass server ez init ITSO CB callback invoked when client wants to shutdown the server void callback c function callback setDone 188 Enabling Applications for Grid Computing with Globus int err globus gass server ez init amp listener amp attr scheme GLOBUS NULL purpose unknown server ez opts callback c function or GLOBUS NULL otherwise GLOBUS NULL or GLOBUS NULL otherwise Various server options can be set as shown in Example 7 16 Example 7 16 Server options settings let s define options for our GASS server unsigned long server ez opts 0UL Files openfor writing will be written a line at a time so multiple writers can access them safely server ez opts GLOBUS GASS SERVER EZ L
232. heExecutionNodes You can use file_stage_in_shared to copy the file in the GASS cache directory Only a symbolic link to the file will be created Example 7 4 Example using file stage in shared globus m0 globus globusrun o s r al amp executable bin 1s arguments 1 count 1 file stage in shared gsiftp m0 tmp File NewFile count 1 total 748 Trwxrwxrwx 1 muser mgroup 122 Mar 14 00 03 NewFile gt home muser globus gass_cache local md5 3b 66 18 bd493014532754516a612f2ac6 m d5 cc 3f 1d aae03be0ceb81e214e2a449ac3 data If a file is already there the job will fail Example 7 5 Example of failure globus m0 globus globusrun o s r al amp executable bin 1s arguments 1 file stage in gsiftp m0 tmp 0 NewFile count 1 GRAM Job failed because the job manager could not stage in a file error code 135 You can use file clean up to fix this problem and delete all files that were staged during the job execution 168 Enabling Applications for Grid Computing with Globus 7 2 Globus Toolkit data grid low level API globus_io To use this API you must activate the GLOBUS_IO module in your program globus module activate GLOBUS IO MODULE Note The complete Globus IO API documentation is available from the Globus project Web site at the following URL http www unix globus org api c globus 2 2 globus io html index html The globus io library was motivated by the desire to provide a uniform I O in
233. hin the grid which would be difficult to administer if the number of systems in the grid becomes large and changes often or users could be Chapter 2 Grid infrastructure considerations 15 assigned to virtual groups For example all authenticated users from a particular domain may be mapped to run under a common user ID on a particular resource This helps separate the individual user ID administration for clients from the user administration that must be performed on the various resources that make up the grid Grid secure communication It is important to understand the communication functions within the Globus Toolkit By default the underlying communication is based on the mutual authentication of digital certificates and SSL TLS To allow secure communication within the grid the OpenSSL package is installed as part of the Globus Toolkit It is used to create an encrypted tunnel using SSL TSL between grid clients and servers The digital certificates that have been installed on the grid computers provide the mutual authentication between the two parties The SSL TLS functions that OpenSSL provides will encrypt all data transferred between grid systems These two functions together provide the basic security services of authentication and confidentiality Other grid communication If you cannot physically access your grid client or server it may be necessary to gain remote access to the grid While your operating system s default t
234. hn t1 itso tupi com Mds Host hn d1 itso dakota com Mds Host hn t0 itso tupi com Mds Vo name bjlinux B Mds Vo name bororos Mds Memory Ram Total freeMB 75 E Mds Vo name dakota Br Mds Host hn d2 itso cana amp Mds Host hn d1 itso a col Mds Memory Vm Total freeMB 1509 F Mds Device ars name processt Mds Memory Ram Total sizeMB 249 Mds Memory Vm Total sizeMB 1509 etho Mds device name cpu 0 Mds Device Group name memory lo Mds Net name Mds Device Group name filesyster e Mds Device Group name networks Mds Net addr Tet Mds Software deployment operatin 192 168 0 41 ie Mds Software deployment MDS 127 0 0 0 8 Mds Net netaddr gt ne amp r amp 8R9Rgqj 192 168 0 0 24 w Apply Add as new Rete j Reftesn j 4 entries found finished Figure 5 4 GQ LDAP browser Broker example In our example we use a basic broker that can be called via a function that takes the number of required Linux nodes as a parameter and a vector of strings as defined in C that will contain the list of nodes when the function returns This simple broker checks the average CPU workload measured in a fifteen minute period of time the number or processors and the CPU speed All this information is available from the GIIS server for each host as Mds Cpu Free 15mnX100 Mds Cpu Total count and Mds Cpu s
235. hows the simplest case where all you need is an RSL string to execute and the resource manager name Note that the GRAMTest class implements the GramJobListener interface This way we get status updates on our job from the resource manager This example will create a new directory on the server called home globus testdir Example 6 6 GRAM example 1 of 2 import org globus Gram import org globus GramJob import org globus GramJobListener Basic GRAM example This example submits a simple Gram Job f public class GRAMTest implements GramJobListener Method called by the listener when the job status changes public void statusChanged GramJob job System out print n Job job getIDAsString Status job getStatusAsString The first thing to do is to create the GRAM job using the RSL string as a parameter Job status listeners can be attached to the GRAM job to monitor the job The job is submitted to the resource manager by issuing job request Tip If you want to check if you are allowed to submit a job to a specific resource manager the method Gram ping rmc can be issued Example 6 7 GRAM example 2 of 2 private void runJob RSL String to be executed String rsl amp executable bin mkdir arguments home globus testdir count 1 Chapter 6 Programming examples for Globus using Java 139 6 4 MDS Resource Manager Contact String rmc t2 itso tupi com Instantiati
236. i gsissh p 24 Nodes i chmod x TMP GenerateDraws amp ProcessID i done for i in 1oop do EXE cd TMP GenerateDraws n grep param amp amp echo GOT IT on HOSTNAME gsissh p 24 Nodes i EXE amp ProcessID i done for i in 1oop do wait ProcessID i done Monitoring The monitoring of each job is managed by the Submit script which reads the content of each file Monitor created by the GenerateDraws executable on each execution node for monitoring we copy locally the Monitor files created on each compute nodes This file content the percentage of tested draws Each files is suffixes by the nodes number statusnum is actually the sum of all the percentage Monitor files devided by 100 When it equals the number of nodes that means that we have finished cH SR SR OSE Chapter 9 Application examples 251 echo Monitoring statussum 0 while statussum NodesNumber do echo sleep 5 we poll every 5 seconds statussum 0 for i in loop do gsiscp q P 24 Nodes i TMP Monitor Monitor i status cat Monitor i statussum status statussum echo Nodes i Monitor cat Monitor i done statussum statussum 100 done How to run it To use this program we need a valid proxy echo password grid proxy init pwstdin Your identity 0 Grid 0 Globus OU itso maya com CN globus Enter GRID pass phrase for this identity Creating proxy gii
237. i Data Grid through NFS locally mounted file system 92 Avaki share mechanism 000000 eee eee eee 93 Storage Tank architecture 0 0 0 eee 95 Replica logical view 96 File replication in a data grid between two organizations 98 Federated databases l l 99 GSl enabled OpenSSH architecture annaa anaana anaa 114 Job submission using non blocking calls 118 Working with a broker LL 125 GQ EDAP DrOWSOE eoe RD Ob rtt os ed ione aac 127 Data management interfaces llle 164 File staging rope ep turpe ERI Ho dtes ote a 167 Using globus io for secure communication 172 GASS Copy example 180 Replica example esses 210 Copyright IBM Corp 2003 All rights reserved ix x 8 1 8 2 8 3 8 4 8 5 8 6 9 1 9 2 9 3 9 4 9 5 9 6 9 7 9 8 10 1 Sample grid portal login screen 216 Simple grid portal welcome screen eee 217 Simple grid portal application flow LL 218 Simple grid portal login flow lle 219 Simple grid portal application submit flow 222 Simple grid portal application information and logout flow 230 Lottery example ke e tee ed Rena aaa 247 Lottery example using Globus commands 255 Problem suitable for Grid enablement lille 263 Gridified SmallBlue 0000 cee ees 266 How to transfer an object via GRAM and GASS 267 Gluster m
238. iate GIIS to search for the resources you require 2 1 4 Data management When building a grid the most important asset within your grid is your data Within your design you will have to determine your data requirements and how you will move data around your infrastructure or otherwise access the required data in a secure and efficient manner Standardizing on a set of grid protocols Chapter 2 Grid infrastructure considerations 25 will allow you to communicate between any data source that is available within your design You also have choices for building a federated database to create a virtual data store or other options including Storage Area Networks network file systems and dedicated storage servers Globus provides the GridFTP and Global Access to Secondary Storage GASS data transfer utilities in the grid environment In addition a replica management capability is provided to help manage and access replicas of a data set These facilities are briefly described below GridFTP The GridFTP facility provides secure and reliable data transfer between grid hosts lts protocol extends the File Transfer Protocol FTP to provide additional features including gt Grid Security Infrastructure GSI and Kerberos support allows for both types of authentication The user can set various levels of data integrity and or confidentiality gt Third party data transfer allows a third party to transfer files between two servers gt
239. iated You read a buffer and call register_write This is an asynch call which returns immediately When it is finished writing the buffer it calls the data callback defined above which 206 Enabling Applications for Grid Computing with Globus reads another buffer and calls register write again The data callback will also indicate when you have hit eof Note that eof on the data channel does not mean the control channel protocol exchange is complete This is indicated by the done callback being called NOTE The for loop is present BECAUSE of the parallelism but it is not CAUSING the parallelism The parallelism is hidden inside the client library This for loop simply insures that we have sufficient buffers queued up so that we don t have TCP steams sitting idle KKK RK KK RK KKK RK KKK KK EK ERK KK KKK KER KKK KEKE ERK EERE EKER ERE K E K Ke for i 0 i lt 2 PARALLELISM amp amp feof fd SUCCESS i ob F F F F F F Ro X buffer malloc MAX BUFFER SIZE rc fread buffer 1 MAX BUFFER SIZE fd globus ftp client register write amp handle buffer rc global offset feof fd SUCCESS data cb void fd global offset rc ERA RR AAA AA RA AAA AAA RK KERR e ke e RARA He e He He e He He Re RARA RARA RARE He He e He He e He He e He Ke Ke He Ke RA The following is a standard thread construct The while loop is required because pthreads may wake up arbitrarily In non thread
240. ibc API provides a set of wrappers to several POSIX system calls The grid developer must use these wrappers to ensure thread safety and portability The globus equivalents to the POSIX calls add the prefix globus libc to the function while prototypes remain identical For example globus libc gethostname should be used instead of gethostname or globus libc malloc instead of malloc Reference information is available at http www globus org common globus libc functions html The globus thread API provides system call wrappers for thread management These include thread life cycle management gt mutex life cycle locking management gt condition variables signal management This API must be used to manage all asynchronous or non blocking Globus calls and their associated callback functions Usually a mutex and a condition variable are associated for each non blocking Globus function and its callback function For this publication we created a sample C object ITSO_CB whose source code is available in ITSO_CB on page 315 The method of this class actually uses the globus thread APIs and can be used as an example of how to do so This class is used in most of our examples Reference information for the thread specific APIs is available at http www globus org common threads functions html 5 1 2 Makefile globus makefile header is the tool provided by the Globus Toolkit 2 2 to generate platform and installation
241. ice Architecture OSGA llle seres 292 10 4 Globus grid Services 293 10 4 1 Index Services 0 0 een 293 10 4 2 Service data browser 00 aaaea naana 293 HOS GRAM Gist hates thorn ee dae Beatties tate 293 10 4 4 Reliable File Transfer Service RFT 000005 296 10 4 5 Replica Location Service RLS eee ee 296 105 SUMMAlYy 3 2 eter ge Pate Sek Se a ee eo aaa LELLA Lai 296 Appendix A Grid qualification scheme 297 A suggested grid application qualification scheme 298 Appendix B C C source code for examples 305 Globus API C wrappers liis 306 ISO GASS TRANSFER pupa i kan tages o et Eva turba ds 306 ITSO_GLOBUS_FTP_CLIENT Ih 311 IT SOS CB3 dod baee ses otra db tirando qe beh bau qd ea bh bus 315 Contents vii viii IESOX GRAMM OB lt oim ie nl imee eee need Pneu 316 StartGASSServer and StopGASSServer LL 324 ITSO bfoker uu ors RR UR EOS ane eee EERTV NIRE E a 327 SmallBlue example nee 331 HelloWorld example 341 L ottery example nu feat aa a Y ER RR 349 C C simple examples 355 gassserver C i 355 Checking credentials llle 357 Submitting ajob LL 358 Appendix C Additional material 365 Locating the Web material 365 Using the Web material 366 How to use the Web material 366 Related publications eese 367 IBM Redbooks Lili 367
242. ices such as life cycle management in a seamless manner gt A standard way to find identify and utilize new grid services as they become available In addition to benefits such as these OGSA will provide for inter operability between grids that may have been built using different underlying toolkits As mentioned Globus Toolkit Version 3 will be the reference implementation for OGSA Though the programming model will change most of the actual APIs that are available with Globus Toolkit V2 2 will remain the same Therefore work done today to implement a grid environment and enable applications will not necessarily be lost OGSA and OGSI OGSA defines a standard for the overall structure and services to be provided in grid environments The Open Grid Services Interface OGSI specification is a companion standard that defines the interfaces and protocols that will be used between the various services in a grid environment The OGSI is the standard that will provide the inter operability between grids designed using OGSA 1 3 Grid components A high level perspective In this section we describe at a high level the primary components of a grid environment Depending on the grid design and its expected use some of these components may or may not be required and in some cases they may be combined to form a hybrid component However understanding the roles of the components as we describe them here will help you understand the considerati
243. ich can be used to generate a Globus Toolkit V3 or V2 2 compatible proxy Example 6 3 Creating a proxy 3 of 3 signing System out printIn Signing proxyType GSIConstants GSI 2 PROXY switch here between GT2 GT3 BouncyCastleCertProcessingFactory factory BouncyCastleCertProcessingFactory getDefault proxy factory createCredential 136 Enabling Applications for Grid Computing with Globus new X509Certificate certificate userKey bits lifetime proxyType proxyCertInfo System out print n Your proxy is valid until proxy getCertificateChain 0 getNotAfter file creation System out printIn Writing File OutputStream out null try out new FileOutputStream proxyFile write the contents proxy save out catch IOException e System err print n Failed to save proxy to a file e getMessage System exit 1 finally if out null try out close catch Exception e System out print ln Exiting createProxy Retrieving credentials from an existing proxy In order to retrieve the credentials from an existing proxy to be used within the application the proxy file must be loaded The proxy file can be located using the cog properties file or by just specifying the file name Example 6 4 Retrieving credentials GlobusCredential gcred new GlobusCredential tmp x509up u1101 cred new GlobusGSSCredentiallImpl g
244. id implementation and application requirements there are many ways in which these pieces can be put together to create a solution 1 5 Summary Grid computing is becoming a viable option in enterprises with the emergence and maturation of key technologies and open standards such as OGSA and OGSI In this chapter we have provided a high level overview of the key facilities that make up grid environments In the next chapter we will describe these in more detail and start describing the various considerations for enabling applications to take advantage of grid environments Chapter 1 Introduction 11 12 Enabling Applications for Grid Computing with Globus Grid infrastructure considerations A grid computing environment provides the virtual computing resource that will be used to execute applications As you are considering application design and implementation it is important to understand the infrastructure that makes up this virtual computing environment When considering whether an application is a good candidate to execute in a grid environment one must first understand the basic structure of a grid the services that are and are not provided and how this can affect the application Once you understand these considerations you will have a better idea of what facilities your application will need to use and how In the last chapter we provided a high level view of how a typical grid and the required services might be structured a
245. idates for grid environments This discussion is based on both grid characteristics and application characteristics In later chapters we provide examples of using the Globus Toolkit to enable applications to run in a grid environment We also dedicate a large portion of this publication to Copyright IBM Corp 2003 All rights reserved 1 2 data handling considerations Though it is one thing to execute one or more application components on various nodes within a grid one must also consider how the application will access and transfer data in an efficient and secure manner Important Though we are focusing on the Globus Toolkit for this publication it is important to note that there are other providers of solutions for grid computing Some of these build on top of the Globus Toolkit to provide key services not directly addressed by Globus IBM has worked closely with these other vendors and sees their work as strategic to the overall evolution of grid solutions Though the products and technologies that these vendors are developing are not necessarily addressed in this publication they are important and should be considered when building a gird or enabling applications for a grid environment Some of these vendors include Platform Computing Provides a set of solutions to help connect manage service and optimize resources in a grid environment http www platform com gt Awaki Solutions to address data access and integrat
246. ided by a specific Globus module This module must be activated before any of the functions can be used The globus_module API provides functions to activate and deactivate the modules gt globus module activate calls the activation function for the specified module if that module is currently inactive gt globus module deactivate calls the deactivation functions for the specified module if this is the last client using that module The function s return value is GLOBUS SUCCESS if it was successful Example 5 2 Globus API module management if globus module activate GLOBUS GRAM CLIENT MODULE GLOBUS SUCCESS cerr lt lt Cannot start GRAM module exit 2 E int rc globus module activate GLOBUS FTP CLIENT MODULE globus assert rc GLOBUS SUCESS globus module deactivate all In the broker in Broker example on page 127 the GLOBUS GRAM CLIENT MODULE is activated and deactivated in the broker code That may be an issue if it is called from a program that thinks that this module is still active after its call Segmentation faults usually occur when Globus functions are called in a non activated module For more information see http www globus org common activation functions html 5 1 4 Callbacks A callback is a C function provided as a parameter to an asynchronous Globus function that is invoked after the call of the function The Globus call is non blocking in that it does not wait for the operation to com
247. idual separated data per job Any job will work on a specified set of input data The data sources and sinks can be of various kinds The following are some questions to be considered gt Can the data be separated for individual use by a defined job It is important that each single job receives a well defined set of input data and has an equally well defined place to leave its computing results gt Is the data replicated in such a way that it is available at any time the assigned job needs to run or rerun This means that we must be careful about changes to the data sets a grid job has to work with One way of solving it can be to establish certain local and temporary data caches that live as long as the grid application runs These data caches are under the control of the grid server or grid portal These caches can act as data sources for more than one job for example if multiple jobs use the same data but perform different actions It may be especially important if one job is launched redundantly or the output of one job determines the input for another job gt Cana separatable data space be created for any job of the grid application A question of how to assure each job s data does not interfere with any other job or processes being executed anywhere on the grid gt Are there interdependencies between jobs in a grid application that require synchronization of the data This may require certain locks on data for read or wr
248. ied to each node so each node works on its local copy If multiple jobs output data to the same file the data is appended to the file Table 7 1 is a list of RSL attributes that are used to stage files in and out Table 7 1 Data movement RSL specific attributes LS NNI CT REESE executable The name of the executable file to run on the remote machine If the value is a GASS URL the file is transferred to the remote GASS cache before executing the job and removed after the job has terminated file clean up Specifies a list of files that will be removed after the job is completed file stage in Specifies a list of remote URL local file pairs that indicate files to be staged to the nodes that will run the job file stage in share Specifies a list of remote URL local file pairs that indicate d files to be staged into the cache A symbolic link from the cache to the local file path will be made file stage out Specifies a list of local file remote URL pairs that indicate files to be staged from the job to a GASS compatible file server gass cache Specifies location to override the GASS cache location globus gass cache by default Chapter 7 Using Globus Toolkit for data management 165 Aes e OOO remote_io_url Writes the given value a URL base string to a file and adds the path to that file to the environment through the GLOBUS_REMOTE_IO_URL environment variable If this is specified as part of a
249. ient HelloFrontEnd 55 0 C g c GLOBUS CPPFLAGS lt o e HelloServer HelloServer C g g I usr local include cc 2 L usr local lib o 0 1ccgnu2 lpthread 1d1 HelloClient HelloClient C g g I usr local include cc 2 L usr local lib o 0 1ccgnu2 lpthread 1d1 HelloFrontEnd HelloFrontEnd C itso gram job C itso cb C itso gass copy C itso gass server C g o I usr local include cc 2 L usr local lib GLOBUS CPPFLAGS GLOBUS LDFLAGS GLOBUS PKG LIBS lccgnu2 lpthread 1d1 348 Enabling Applications for Grid Computing with Globus Lottery example Below is a sample for emulating a lottery To compile GenerateDraws C issue g o GenerateDraws 0 3 GenerateDraws C GenerateDraws C finclude cstdlib include unistd h include list include algorithm include fstream int GetARandomNumberBetweenlAnd60 returnrandom RAND MAX 60 1 h void initrandom unsigned seed define RANDSIZE 256 static char randstate RANDSIZE initstate seed randstate RANDSIZE main int argc char argv initrandom getpid seeding for a new sequence of pseudo random integers let generate 8 number between 1 and 60 list long int Series long int n long long DrawNumber InitialDrawNumber ofstream OutputFileMonitor OutputFileMonitor open Monitor DrawNumberzatol1 argv 1 Initial DrawNumber DrawNumber do int i Series clear fo
250. ifferent purposes and the application development tools market is constantly changing 3 13 Qualification scheme for grid applications In this section a usable format of a qualification scheme for grid applications is provided We also provide a criteria list that may be looked at as a knock out list That is it includes attributes of an application or its requirements that may inhibit an application from being a good candidate for a grid environment The list may not be complete and depends on the local circumstances of resources and infrastructure The qualification scheme acts as a basis for architecture and project planning for a grid application 3 13 1 Knock out criteria for grid applications Earlier sections have discussed considerations for grid enabling an application from the perspectives of infrastructure and application functionality However not all applications lend themselves to successful or cost effective deployment on a grid A number of criteria may make it very difficult require extensive work effort or even prohibit grid enabling an application Criteria below may preclude deploying an application to the grid without having to perform an extensive analysis of the application Some facts such as temporary data spaces data type conformity across all nodes within the network appropriate number of SW licences available in the network for the grid application higher bandwidth or the degree of complexity of the job flow
251. ify the application The scale here low to high could identify a range from no effort simple to a show stopper at the other extreme Skills A weight factor of the available skills of the project team Resources A weight factor that assesses the capacity and type of resources in the grid for example operating system file system network and so on Comments Any comments the evaluator wishes to record Each criterion would be analyzed and a rating provided for the relevant weight factors bearing in mind that many of the criteria may have a combined impact on grid enabling the application A suggested range of High H Medium M or Low L is shown but this could obviously be changed to a numeric or other scale After evaluating the application against the chosen criteria show stoppers should be identified and potential workarounds addressed As described above the table identifies several weight factors that could be used to evaluate an application The factors shown in the table are not exhaustive and the reader may wish to consider adding additional factors for example technologies or architecture pattern used specific to their environments 298 Enabling Applications for Grid Computing with Globus Table A 1 Qualification scheme for grid applications Weight factors H M L Com ment Range Effort Skills show low to high stoppers efforts special care base values Parallel gt networked gt serial
252. ilable resources within the grid and their statuses A broker service could be developed that utilizes MDS Broker 0 m Directory Service Portal GSI Security amr Figure 1 3 Broker service 8 Enabling Applications for Grid Computing with Globus 1 3 4 Scheduler Once the resources have been identified the next logical step is to schedule the individual jobs to run on them If a set of standalone jobs are to be executed with no interdependencies then a specialized scheduler may not be required However if it is desired to reserve a specific resource or to ensure that different jobs within the application run concurrently for instance if they require inter process communication then a job scheduler should be used to coordinate the execution of the jobs The Globus Toolkit does not include such a scheduler but there are several schedulers available that have been tested with and can be utilized in a Globus grid environment It should also be noted that there could be different levels of schedulers within a grid environment For instance a cluster could be represented as a single resource The cluster may have its own scheduler to help manage the nodes it contains A higher level scheduler sometimes called a meta scheduler might be used to schedule work to be done on a cluster while the cluster s scheduler would handle
253. iles created on each compute nodes This file content the percentage of tested draws Each files is suffixes by the nodes number statusnum is actually the sum of all the percentage Monitor files devided by 100 When it equals the number of nodes that means that we have finished echo Monitoring statussum 0 while statussum NodesNumber do echo sleep 5 we poll every 5 seconds statussum 0 for i in 1oop do gsiscp q P 24 Nodes i TMP Monitor Monitor i status cat Monitor i statussum status statussum echo Nodes i Monitor cat Monitor i done statussum statussum 100 done cleanup the tmp directory for i in 1oop do wait ProcessID i gsissh p 24 Nodes i rm fr TMP amp Chapter 9 Application examples 249 ProcessID i done Submit uses the broker mds program described in Broker example on page 127 to get the host names that it will submit the jobs to by using gsissh for n in mds NodesNumber xargs do Nodes i n i i 1 done The number of draws per node is determined by the variable n and the number of jobs by the variable NodesNumber n 100000 NodesNumber 10 Sandboxing Each execution host uses a sandbox directory in each execution node This directory is created in the local home directory of the user under which the job is executed This directory is configured by the TMP variable set up as lt execution host
254. ill use a mutex and condition variable the same way moni tor Lock wait until it is finished 186 Enabling Applications for Grid Computing with Globus while monitor IsDone monitor Wait monitor UnLock h To compile this example uses the following commands g I usr local globus include gcc32 L usr local globus lib o gasscopy gasscopy C lglobus gass copy gcc32 lglobus common gcc32 To run the program you need to start a GASS server on the remote site for example globus m0 globus grid proxy init Your identity 0 Grid 0 Globus 0U itso maya com CN g1obus Enter GRID pass phrase for this identity Creating PROXY sexa se rette Pede Te D Rd ls Toba tetany Done Your proxy is valid until Sat Mar 1 02 40 36 2003 globus m0 globus globus gass server p 5000 https m0 itso maya com 5000 On the client side to copy the file tmp TEST to m0 itso maya com by renaming it to NEWTEST issue globus t1 globus grid proxy init Your identity 0 Grid 0 Globus OU itso maya com CN globus Enter GRID pass phrase for this identity Creating Proxy ics Waster 39 qo eA aia oe RR ds wale CTS Le n Done Your proxy is valid until Sat Mar 1 02 40 36 2003 globus t1 globus gasscopy tmp TEST https m0 itso maya com 5000 NEWTEST On mo you can check that NEWTEST appears in the target directory Note If you use gsissh to connect from mO to t1 after you issued grid proxy init you do not need to rei
255. imes but with different parameters for which it generates differing results A major improvement for the performance of the grid application may be derived by transferring the input data ahead of time as close as possible to the compute nodes Other cases of data separation More unfavorable cases may appear when jobs have dependencies on each other The application flow may be carefully checked in order to determine the level of parallelism to be reached The number of jobs that can be run simultaneously without dependences is important in this context In this section a few cases are discussed in more detail from the data perspective For independent jobs there needs to be synchronization mechanisms in place to handle the concurrent access to the data The Globus Toolkit does not provide any synchronization mechanisms to manage these dependencies and therefore these cases need to be managed by the grid application developers However Globus core modules provide portable mutex condition variables and thread implementations that help to implement such mechanisms Synchronizing access to one output file This case is shown in Figure 4 5 on page 83 Here all jobs work with common input data and generate their output to be stored in a common data store 82 Enabling Applications for Grid Computing with Globus Figure 4 5 All jobs works on the same data and write on the same data set The output data generation implies t
256. implements data brokering used by grid applications to retrieve their data The SRB consists of three components The metadata catalog MCAT SRBservers SRBclients The MCAT is implemented using a relational database such as Oracle DB2 PostGresSQL or Sybase It maintains a Unix name space file name directories and subdirectories and a mapping of each logical name to a set of physical attributes and a physical handle for data access The physical attributes include the host name and the type of resource Unix File system HPSS archive database and so on The MCAT server handles requests from the SRB servers that may be information queries as well as instructions for metadata creation and update SRB in conjunction with the Metadata Catalog MCAT provides a way to access data sets and resources based on their attributes rather than their names or physical locations Each data stored in SRB has a logical name that can be used as a handle for data operation The physical location of data is logically mapped to the data sets that may reside on different storage systems A server manages brokers a set of storage resources The supported storage resources are Mass Storage system such as HPSS UniTree and DMF and ADSM as file systems SRB provides an API for grid application developers in the following programming languages C C Perl Python and Java For management purposes SRB also provides a set of Unix shell command
257. imum amount of memory in MBs required for the job gt minMemory Specifies the minimum amount of memory in MBs required for the job gt hostCount Specifies the number of nodes in a cluster required for the job gt environment Specifies environment variables that are required for the job gt jobType Specifies the type of job single process multi process mpi or condor gt maxTime Specifies the maximum execution wall or cpu time for one execution gt maxWallTime Specifies the maximum walltime for one execution gt maxCpuTime Specifies the maximum cpu time for one execution gt gramMyjob Specifies the whether the gram myjob interface starts one process thread independent or more collective The following examples show how RSL scripts are used with the globusrun command The following is a list of files included in this example gt MyScript sh Shell script that executes the 1s al and ps ef commands bin sh x Is al ps ef gt MyTest rsl RSL script that calls the shell script tmp MySrcipt sh It runs the script in the tmp directory and stores the standard output of the script in tmp temp The contents are below amp rsl substitution TOPDIR tmp executable TOPDIR MyScript sh directory tmp stdout tmp temp count 1 Chapter 2 Grid infrastructure considerations 19 20 gt MyTest2 rsl RSL script that executes the bin ps ef command and stores the standard output of the
258. in the replica catalog as well of the information needed to connect to the LDAP server a user and a password The Globus Toolkit V2 2 uses an LDAP directory so the URL for a collection follows the format Idap host port dn where dn is the distinguished name of the collection The HOST format is therefore host collection URL manager manager DN password lt file gt Two environment variables can be used to avoid typing the host and manager option each time GLOBUS REPLICA CATALOG HOST for the logical collection distinguished name GLOBUS REPLICA CATALOG MANAGER for the manager distinguished name file contains the password used during the connection OBJECT indicates which entry in the replica catalog the command will act upon collection for a collection that was specified in the host option location name logicalfile lt name gt ACTION determines which operations will be executed on the entry There are four categories Creation deletion attributes modifications files names manipulation in the logical collection file lists and location file lists and finally search operations See the Globus documentation for more information 7 5 2 Replica example In the following example scenario we propose to create a logical collection called itsoCollection in the Replica Catalog created in Installation on page 211 This collection consists of five files that are located on two diff
259. int In Requesting Job try job request rmc catch Exception e System out println Error e getMessage We request the job and deactivate GASS using the deactivator when the job is done Example 6 33 Batch GASS example 4 of 4 public static void main String args System out print n Starting GRAM amp GASS in Batch mode GASSBatch run new GASSBatch run startGassServer Chapter 6 Programming examples for Globus using Java 157 run runJob System out print ln Job Sumbitted Done Deactivator deactivateAl1 6 7 2 Interactive GASS example In interactive mode we will reroute the output of the application to our client instead of storing it Example 6 34 Interactive GASS example 1 of 3 import import import import import import import org globus gram Gram org globus gram GramJob org globus gram GramJobListener org globus io gass server GassServer org globus io gass server JobOutputListener org globus io gass server JobOutputStream org globus util deactivator Deactivator Example of using GRAM amp GASS in interactive mode public class GASSInteractive implements GramJobListener JobOutputListener private GassServer gServer null private String gURL null private JobOutputStream oStream private JobOutputStream eStream null OutputStream null ErrorStream private String JobID null To Start the GASS Server priva
260. ion http www avaki com gt DataSynapse Supplies a CPU scavenging platform http www datasynapse com gt United Devices Provides a grid application framework for CPU scavenging http www ud com Enabling Applications for Grid Computing with Globus 1 1 High level overview of grid computing The most common description of grid computing includes an analogy to a power grid When you plug an appliance or other object requiring electrical power into a receptacle you expect that there is power of the correct voltage to be available but the actual source of that power is not known Your local utility company provides the interface into a complex network of generators and power sources and provides you with in most cases an acceptable quality of service for your energy demands Rather than each house or neighborhood having to obtain and maintain their own generator of electricity the power grid infrastructure provides a virtual generator The generator is highly reliable and adapts to the power needs of the consumers based on their demand The vision of grid computing is similar Once the proper kind of infrastructure is in place a user will have access to a virtual computer that is reliable and adaptable to the user s needs This virtual computer will consist of many diverse computing resources but these individual resources will not be visible to the user just as the consumer of electric power is unaware of how his electricity is bein
261. ion see http ww citi umich edu projects nfsv4 For NFS VA for the ASCI project see http ww citi umich edu projects asci General Parallel File System GPFS allows shared access to files that may span multiple disk drives on multiple nodes GPFS is currently supported for Linux and AIX operating systems A high performance inter connect switch such as Myrinet or a SP switch is mandatory to achieve acceptable performance GPFS is installed on each node as a kernel extension and appears to jobs as just another file system This implies that the jobs only need to call normal I O system calls to access the files The GPFS advantages are gt The jobs still use standard file system calls gt The jobs can concurrently access files from different nodes with either read or write I O calls gt Increases bandwidth of the file system by striping across multiple disks gt Balances the load across all disks to maximize throughout gt Supports large amounts of data As all nodes in a grid cannot be connected to the same high performance network GPFS is not the ultimate solution for the grid but is a good solution when local file sharing is requested on a local cluster that will process grid jobs GPFS is also a good candidate for the permanent storage of very large files that need to be partially copied to other nodes on the grid by using the Globus Toolkit Chapter 4 Data management considerations 91 Avaki Data Grid solution
262. ion flow vs job flow For the remainder of the book an application flow is the flow of work between the jobs that make up the grid application The internal flow of work within a job itself is called job flow Chapter 3 Application architecture considerations 45 Analyzing the type of flow within an application delivers the first determining factor of suitability for a grid This does not mean that a complex networked application flow excludes implementation on a grid nor does a simple flow type determine an easy deployment on a grid Rather besides the flow types the sum of all qualifying factors allows for a good evaluation of how to enable an application for a grid There are three basic types of application flow that can be identified gt Parallel gt Serial gt Networked The following sections discuss each of these in more detail 3 2 1 Parallel flow If an application consists of several jobs that can all be executed in parallel a grid may be very suitable for effective execution on dedicated nodes especially in the case when there is no or a very limited exchange of data among the jobs From an initial job a number of jobs are launched to execute on preselected or dynamically assigned nodes within the grid Each job may receive a discrete set of data and fulfills its computational task independently and delivers its output The output is collected by a final job or stored in a defined data store Grid services such as a
263. iped FTP server You can do this by using the function globus ftp client operationattr set layout Example 7 23 Parallel transfer example extracted from Globus tutorial f Fei keke ke keke ke ke eke ke e ke ke e ke ke e he He e he Ae Ske he Ae Ske he She She e ke Ske e ke She e He She e He He e He He S He Ae Ske he Ae Ske e he Ske e ke Ske e He Ske e He ke e He Ke e He Globus Developers Tutorial GridFTP Example Authenticated Put w attrs Operation attributes are used in this example to set a parallelism of 4 This means the transfer must run in extended block mode MODE E Note that while this program shows proper usage of the Globus GridFTP client library functions it is not an example of proper coding style Much error checking has been left out and other simplifications made to keep the program simple e e Ke e e ke e e ke e e he e He e e e e e e RK ERR KKK RK KEK KK EKER KK KER KKK RK KR KARA RK KEKE KEKE KEREKER oko F HF include lt stdio h gt include globus_ftp_client h static globus_mutex_t lock static globus_cond_t cond static globus_bool_t done int global_offset 0 define MAX_BUFFER_SIZE 64 1024 define ERROR 1 202 Enabling Applications for Grid Computing with Globus define SUCCESS 0 define PARALLELISM 4 BRR RR RRR RRR RRR ER de ke ERR KK RR KK RRR KR RR KR ERK KERR EKER ERR KK RK KARA ARA RARA done_cb A pointer to this function is passed to the call to globus_ftp_client_put and al
264. ipts recompile software and so on The install process should be equally straightforward for host management and client nodes regardless of the potentially heterogeneous nature of the nodes in terms of operating system or configuration Unobtrusive criteria Transparency and ease of use as well job submission and control are not obvious items but are essential for a good grid design gt The use of a grid should be transparent to the user The grid portal should isolate the user from the need to understand the makeup of the grid gt Is documentation available or required for all categories of user including executive level summaries on the nature and use of the grid programmer and administrative support staff Where possible the documentation should provide demos and examples for use gt Ease of resource enrollment after any installation steps should provide simple configuration of grid parameters to enable the node and its resources to be a participant on the grid The administrator of the grid or user of a donor machine should not require special privileges to enroll gt Ease of job submission should alleviate the need for the user to understand the makeup of the grid search for available resources or have to provide complex parameters other than from the business nature of the application It may be appropriate to provide multiple channels for job submission including command line although this has not typically provided eas
265. is HelloServer The source code is provided in HelloWorld example on page 341 The executable for the front end server is HelloFrontEnd and starts HelloServer remotely The source code is provided in HelloWorld example on page 341 central storage 7 i libCommonC sources submit transfer transfer 4 7 front end 7 application server submit library compilation launch the HelloServer application libCommonC HelloServer hello receive a ticket and an IP HelloClient Figure 9 8 Hello World example with dynamic library dependencies issues 9 3 2 Dynamic libraries dependencies In this example the application depends on a dynamic library GNU CommonC http www gnu org software commonc that is not installed by default on the remote servers To solve this issue the front end server installs at startup the dynamic library on the remote server by compiling it on this server This is an interesting solution to avoid runtime issues like libc or libstdc dependencies or other library dependencies that Common C depends on This Chapter 9 Application examples 281 library can also be recompiled on different architectures with only the copy of the source code to store We store the source copy of the library on a storage server mO in the example The script Compile is used to compile the library and install it Example 9 14 Compile script
266. it string string void Cancel void SetJobContact const char void Wait void SetFailed bool HasFailed h fendif itso gram jobs callback h ifndef ITSO GRAM JOBS CALLBACK H define ITSO GRAM JOBS CALLBACK H include lt cstdio gt include lt string gt include lt map gt include globus gram client h finclude itso cb h class ITSO GRAM JOBS CALLBACK class ITSO GRAM JOB class ITSO GRAM JOBS CALLBACK globus mutex t JobsTableMutex char callback contact This is the identifier for the callback returned by globus gram job request mapsstring ITSO GRAM JOB JobsTable void Lock void UnLock public ITSO GRAM JOBS CALLBACK ITSO GRAM JOBS CALLBACK Appendix B C C source code for examples 317 void Add string ITSO GRAM JOB void Remove char char GetURL ITSO GRAM JOB GetJob char h class ITSO GRAM JOB public ITSO CB char jobcontact bool failed ITSO GRAM JOBS CALLBACK callback public ITSO0 GRAM JOB ITSO GRAM JOBS CALLBACK f failed false jobcontact NULL callback f ITSO GRAM JOB bool Submit string string void Cancel void SetJobContact char void Wait void SetFailed bool HasFailed h endif itso_gram_jobs_callback C include itso gram jobs callback h namespace itso gram jobs static void callback func void user callback arg char job contact int state int errorcode
267. ite access It also means that we must consider how failures while producing data are to be solved among any dependent jobs Chapter 4 Data management considerations 73 4 1 2 Shared data access Related to the separation of data for individual jobs is the question of sharing data access with concurrent jobs and other processes within the network Access to data input and the data output of the jobs can be of various kinds The following considerations are kept generic so that they can be applied to the actual cases appropriately During the planning and design of the grid application you must consider whether there are any restrictions on the access of databases files or other data stores for either read or write The installed policies need to be observed and depending on the task the job has to fulfill sufficient access rights have to be granted to the jobs Another topic is the availability of data in shared resources It must be assured that at run time of the individual jobs the required data sources are available in the appropriate form and at the expected service level Potential data access conflicts need to be identified up front and planned for You must ensure that individual jobs will not try to update the same record at the same time nor dead lock each other Care has to be taken for situations of concurrent access and resolution policies imposed Federated databases If a job must handle large amounts of data in various
268. itle Grid Job Status out printIn html out printIn head out printIn title title lt title gt out printIn lt head gt out printIn lt body bgcolor cfd09d text 000099 gt out println hl align center gt title lt h1 gt myJobIds jspBean getJobIds Chapter 8 Developing a portal 239 int size myJobIds length if size gt 0 out printIn table border 1 gt out printIn lt tr gt out print lt td gt lt b gt Job Id lt td gt out printIn lt td gt Job Status lt b gt lt td gt out printIn tr for int i 0 i size i String myJobId myJobIds i out printIn lt tr gt out print lt td gt myJobId lt td gt out printIn td doGetStatus myJobId lt td gt out printIn tr out printIn table out printIn body out printIn lt htm1 gt private void getResult String myJobIds String title Grid Application Run Result out printIn html out printIn head out printIn title title lt title gt out print ln lt head gt out println body bgcolor cfd09d text 000099 gt out println hl align center gt title lt h1 gt myJobIds jspBean getJobIds int size myJobIds length if size gt 0 out printIn table border 1 gt out printIn lt tr gt out print l
269. itself calls the setDone method of the ITSO CB class through the request cb attribute The RSL submission string is passed as an argument as well as the host name of the execution node to globus gram client register job request GLOBUS GRAM PROTOCOL JOB STATE ALL specifies that we want to monitor all states done failed staging files The ITSO GRAM JOB object itself is passed as an argument void this This way the callback can invoke its SetRequestDone method See Example 5 14 on page 121 Example 5 13 globus gram client register job request call int rc globus gram client register job request res c str rsl c str GLOBUS GRAM PROTOCOL JOB STATE ALL callback contact GLOBUS GRAM CLIENT NO ATTR itso gram job request callback void this Here is an example of a globus gram client register job request callback The callback is called whether the job has been submitted successfully or not 120 Enabling Applications for Grid Computing with Globus Example 5 14 globus_gram_client_register_job_request callback static void request callback void user callback arg globus gram protocol error t failure code const char job contact globus gram protocol job state t state globus gram protocol error t errorcode ITSO GRAM JOB Request ITSO GRAM JOB user callback arg cout Contact on the server job contact endl Request SetRequestDone job contact The callback calls
270. ixed platform environments 40 modules 107 Monitoring and Discovery Service see MDS MPI 66 MPICH G2 34 66 mutex 109 201 mutex life cycle 106 Index 375 N naming 292 Network File System see NFS network file systems 26 network topology 39 networked flow 46 49 NFS 91 non blocking calls 117 non functional requirements 35 O OGSA 3 5 11 33 54 OGSI 6 11 58 290 Open Grid Service Architecture 292 Open Grid Services Architecturer see OGSA open source licensing 63 open source software 63 OpenSSH 15 OpenSSL 7 16 170 operating systems 54 OSI 64 overview of grid 3 P pache 63 parallel application flow 46 47 parallel applications 52 parallelism 82 202 parallelization 48 partial file transfer 26 201 Particle Physics Data Grid 103 peer to peer 88 peer to peer computing 4 performance 36 Perl 53 66 persistent license 64 persistent storage 38 Petascale Virtual Data Grid 102 ping 122 Platform Global License Broker 66 Platform Globsal License Broker 66 portal 6 34 215 considerations 35 integration with application 232 portal example 216 portal login flow 219 portal security 233 portType 295 POSIX 169 power grid 3 producers 46 programming environment 106 programming language considerations 53 programming model 5 proxy 15 134 proxy certificate 7 proxyType variable 136 Public Key Infrastructure 84 Puissance 4 262 Python 5 66 Q qualification scheme 69 298 R Redbooks W
271. job restart RSL the job manager will update the file s contents This is intended for jobs that want to access files via GASS but the URL of the GASS server has changed due to a GASS server restart stdin The name of the file to be used as standard input for the executable on the remote machine If the value is a GASS URL the file is transferred to the remote GASS cache before executing the job and removed after the job has terminated stdout The name of the remote file to store the standard output from the job If the value is a GASS URL the standard output from the job is transferred dynamically during the execution of the job stderr The name of the remote file to store the standard error from the job If the value is a GASS URL the standard error from the job is transferred dynamically during the execution of the job 166 Enabling Applications for Grid Computing with Globus GridFTP Server data movement GRAM 71 Job Manager sans i 1 submits RSL string i gatekeeper E gt we gt cache Execution node Figure 7 2 File staging Let us consider an example where a program called MyProg generates an output file named OutputFileGenerated on the execution node This output file is retrieved from the execution node and saved as tmp RetrievedFile on the machine where the globusrun command was issued Example 7 1 Staging files out with RSL globusrun o s
272. ker developped for the publication see chapter 8 mds executable for node in mds NodesNumber xargs do Nodes i node loop loop i i i 1 done echo The number of draws tested is n a sort the numbers in the specified draw 2 45 23 12 32 43 becomes 2 12 23 32 43 45 so that we could use grep to test this draw and the ouput of the draw programs param echo a tr n sort n xargs parrarell transfer of the draw executable we submit jobs in the background get their process id and uses the wait command to wait for their completion this method is also used for the jobs submission echo Transferring executable files for i in 1oop do gsissh p 24 Nodes i d TMP mkdir TMP amp ProcessID i done for i in 1oop do wait ProcessID i 248 Enabling Applications for Grid Computing with Globus gsiscp P 24 GenerateDraws Nodes i TMP amp ProcessID i done for i in 1oop do wait ProcessID i gsissh p 24 Nodes i chmod x TMP GenerateDraws amp ProcessID i done file should be made executable on all the execution nodes echo Jobs submission to the grid for i in 1oop do wait ProcessID i echo Nodes i EXE cd TMP GenerateDraws n grep param amp amp echo GOT IT on HOSTNAME gsissh p 24 Nodes i EXE amp ProcessID i done for monitoring we copy locally the Monitor f
273. kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk main int argc char argv First thing to do activate the module globus module activate GLOBUS IO MODULE globus io attr t io attr globus io tcpattr init amp io attr 174 Enabling Applications for Grid Computing with Globus gss cred id t credential handle GSS C NO CREDENTIAL if getCredential amp credential_handle cerr lt lt you are not authenticated exit 1 globus io secure authorization data t auth data globus io secure authorization data initialize amp auth data globus result t t globus io attr set secure authentication mode amp io attr GLOBUS IO SECURE AUTHENTICATION MODE GSSAPI use GSI credential handle globus io attr set secure authorization mode amp io attr GLOBUS IO SECURE AUTHORIZATION MODE SELF amp auth data We want encrypted communication if not use GLOBUS IO SECURE CHANNEL MODE CLEAR globus io attr set secure channel mode amp io attr GLOBUS IO SECURE CHANNEL MODE GSI WRAP globus io attr set secure protection mode amp io attr GLOBUS IO SECURE PROTECTION MODE PRIVATE encryption will see later for the delegation globus io attr set secure delegation mode amp io attr GLOBUS IO SECURE DELEGATION MODE FULL PROXY globus io attr set secure proxy mode amp io attr GLOBUS IO SECURE PROXY MODE MANY The first argument like http m0 itso tupi co
274. l restrictive to all permissive Between these two extremes there are numerous models in the middle ground where licenses are linked to a named user personal license a workgroup a single server or a certain number of CPUs in a cluster to a server farm or linked to a certain maximum number of concurrent users and others Software licenses are given with a one time charge or on a monthly license fee base They can include updates or require purchase of new licenses All this varies from vendor to vendor and from customer situation to customer situation depending on individual agreements or other criteria Software licenses may allow for the migration of software from one server to another or may be strictly bound to a certain CPU Listing all possible software licensing models could easily fill a book but we cover a few below 62 Enabling Applications for Grid Computing with Globus Service Provider License Agreement Subscriber Access Licenses SALs are offered by service providers for example on a pay per use basis or as a flat rate for a certain maximum number of access times per month week year IT service providers in turn may acquire software licenses from ISVs for use by their customers or they may simply host software for which the end user will pay directly to the providing ISV according to their agreed license model Open source licensing Another complexity is added when a software product is built that contains or
275. l the other high level transfer operations It is called when the transfer is completely finished i e both the data channel and control channel exchange Here it simply sets a global variable done to true so the main program will exit the while loop KKK RK KKK KKK KKK KHER KK ERK KE RK KEKE KEKE RRR KERR ARA RARA AAA KERR KERR ERE oko F X static void done cb void user arg globus ftp client handle t handle globus object t err char tmpstr if err fprintf stderr s globus object printable to string err globus mutex lock amp lock done GLOBUS TRUE globus cond signal amp cond globus mutex unlock amp lock return BRR AAA AAA ARA AAA AA RARA AAA AA RA AAA AAA ERK ERK EKER KK EKER KERR KK KER KR ERR EERE RK data_cb A pointer to this function is passed to the call to globus_ftp_client_register_write It is called when the user supplied buffer has been successfully transferred to the kernel Note that does not mean it has been successfully transmitted In this simple version it justs reads the next block of data and calls register write again HR K RK KKK KEK KKK KK ERK ERR KKK e Ske KEKE KEKE RK EKER AAA A RK EERE KERR EERE RERKEKERE f static void data cb void User arg globus ftp client handle t handle globus object t err globus byte t buffer globus size t length globus off t offset globus bool t eof Chapter 7 Using Globus Toolki
276. lation GSIssh middleware is developed by the National Science Foundation Initiative and is not included in the Globus Toolkit Therefore it needs to be installed on top of Globus Toolkit 2 2 and its installation requires the Globus Packaging Technology GPT It can be downloaded at the following site http ww nsf middleware org NMIR2 download asp GCSS The installation instructions can be found at http ww nsf middleware org documentation NMI R2 0 A11 allserver_install htm GSIssh can be either installed by using a binary bundle already compiled or by using a source bundle that needs to be compiled on site The installation procedure is very well explained on the NMI Web site see above The following steps summarize the installation procedure for GSIssh using the Source package in the case where the Globus Toolkit 2 has been already installed 1 Download the GSIssh package from the NMI Web site 2 Set up your environment according your Globus Toolkit environment export GPT_LOCATION usr local globus export GLOBUS LOCATION usr 1local globus 3 Build the bundle using GPT s build command GPT_LOCATION sbin gpt build static gsi_openssh NMI 2 1 src_bundle tar gz gcc32 4 Run any post install setup scripts that require execution GPT LOCATION sbin gpt postinstall 5 Use GPT s verify command to verify that all of the files were installed properly GPT LOCATION sbin gpt verify 116 Enabling Applications for Grid Compu
277. launched for a second time if it has not changed any persistent data prior to its error state This process can be then repeated until final successful completion However it may make sense that failures be handled by the grid server to allow a more sophisticated way to get to job completion By building checkpoint and restart capabilities into the job and making its state available to other services within the grid the job could be restarted where it failed even on a different node 3 7 Job topology For a grid application there are various topology related considerations There are certain architectural requirements covering the topology of jobs and data When designing the grid application architecture some of the key items to consider are Where grid jobs have to or can run How to distribute and deploy them over a network How to package them with essential data Where to store the executables within the network How to determine a suitable node for executing the individual jobs YYYY Y The following are some factors that should be included in the consideration of the above items Location of the data and its access conditions for the job Amount of data to be processed by the jobs gt Interfaces needed for any interaction with certain devices gt Inter process communication needed for the job to complete its tasks Availability and performance values of the individual nodes at time of execution Size of th
278. lements sophisticated query operations that include gt Logic operators AND amp OR and NOT Value operators gt lt for approximate matching Chapter 5 Getting started with development in C C 125 For example here is a way to look up host names of the resources of all nodes running Linux that use a Pentium processor with a CPU speed greater than 500 Mhz ldapsearch x p 2135 h m0 b mds vo name maya o grid s sub amp Mds 0s name Linux Mds Cpu model Pentium Mds Cpu speedMHz gt 500 Mds Host hn version 2 filter amp Mds 0s name Linux Mds Cpu model Pentium II Mds Cpu speedMHz gt 500 requesting Mds Host hn al itso apache com apache maya Grid dn Mds Host hn al itso apache com Mds Vo name apache Mds Vo name maya o Grid Mds Host hn al itso apache com t2 itso tupi com tupi maya Grid dn Mds Host hn t2 itso tupi com Mds Vo name tupi Mds Vo name maya o Grid Mds Host hn t2 itso tupi com tl itso tupi com tupi maya Grid dn Mds Host hn tl itso tupi com Mds Vo name tupi Mds Vo name maya o Grid Mds Host hn tl itso tupi com The following command can be included in a program to retrieve the list of the machines that match the criteria dluser d1 dluser ldapsearch x p 2135 h m0 b mds vo name maya o grid s sub amp Mds 0s name Linux Mds Cpu model Pentium Mds Cpu speedMHz 500 Mds Host hn awk Mds Host hn print 2
279. lient C finclude itso globus ftp client h namespace itso globus ftp client static void done cb void user arg globus ftp client handle t handle globus object t err ITSO CB f ITSO CB user arg if err cerr lt lt globus object printable to string err h f setDone return bs static void data cb void User arg globus ftp client handle t handle globus object t err globus byte t buffer globus size t length globus off t offset globus bool t eof ITSO GLOBUS FTP CLIENT 1 ITSO GLOBUS FTP CLIENT user arg if err fprintf stderr 5s globus object printable to string err else if eof Appendix B C C source code for examples 313 1 gt Transfer buffer length offset else return data cb bs ITSO GLOBUS FTP CLIENT ITSO GLOBUS FTP CLIENT char f char dst fd fopen f r globus ftp client handle init amp handle GLOBUS NULL globus result t r globus ftp client put amp handle dst GLOBUS NULL GLOBUS NULL itso globus ftp client done cb this bs ITSO_GLOBUS_FTP_CLIENT ITSO GLOBUS FTP CLIENT fclose fd globus ftp client handle destroy amp handle bs void ITSO GLOBUS _FTP_CLIENT StartTransfer int rc rc fread buffer 1 MAX_BUFFER_SIZE fd globus_ftp_client_register_write amp handle buffer rc 0 feof fd SUCCESS itso globus ftp client data cb void this bs
280. ling Applications for Grid Computing with Globus l atoi c while 1 lt 1 1 gt XSIZE Current CanPlay 1 Current Play 1 BLACK if Current HasWon 1 BLACK Current Display break h Serialize to disk the Current variable so that it could be used by the GRAM subsystem and transferred on the remote execution nodes Current ToDisk GAME Current Display cout endl remove eval file for each new jobs submission otherwise results will be appended to the same files unlink eval for i 0 1 8 1 cout lt lt submission on lt lt node i lt lt endl char tmpc 2 sprintf tmpc d i build the RSL commands rs req amp executable SmallBlueSlave arguments rsl_reqt tmpc 0 rsl_reqt stdout https rs req hostname rs req 10001 rsl req get current dir name rs req eval stdin https rs req hostname rs req 10001 rs req get current dir name rs req GAME count 1 submit it to the GRAM if Current CanPlay i if job i Submit node i rs req exit 1 P And Wait for i 0 i 8 1 if Current CanPlay i job i gt Wait worse case 1 100000 Chapter 9 Application examples 273 Here we are reading the eval files All the jobs has been completed so we should have all the results in the eval file ifstream results eval while results eof results gt gt k gt
281. ling Applications for Grid Computing with Globus specifically its performance and turn around time Applications with many individual jobs that each may be affected or controlled by a load balancing system can benefit from the improved overall performance and throughput of the grid but may also require more complicated mechanisms to handle the complexity of having its jobs delayed or moved to accommodate the overall grid 2 1 7 Broker As already described the role of a broker in a grid environment can be very important It is a component that will likely need to be implemented in most grid environments though the implementation can vary from relatively simple to very complex The basic role of a broker is to provide match making services between a service requester and a service provider In the grid environment the service requesters will be the applications or the jobs submitted for execution and the service providers will be the grid resources With the advent of OGSA the future service requester may be able to make requests of a grid service or a Web service via a generic service broker A candidate for such a generic service broker may be IBM WebSphere Business Connection which is currently a Web services broker The Globus toolkit does not provide the broker function It does however provide the grid information services function through the Monitoring and Discovery Service MDS The MDS may be queried to discover the propertie
282. ll rights reserved Licensed Materials Property of IBM Note to US Government users Documentation related to restricted rights Use duplication or disclosure is subject to restrictions set forth in GSA ADP Schedule with IBM Corp This page may contain other proprietary notices and copyright information the terms of which must be observed and followed This program may be used executed copied modified and distributed without royalty for the purpose of developing using marketing or distributing package com ibm itso mygridportal web import java io IOException import javax servlet import javax servlet ServletException import javax servlet http HttpServlet import javax servlet http HttpServletRequest import javax servlet http HttpServletResponse import java io import java util Chapter 8 Developing a portal 225 version 1 0 author xf public class Application extends HttpServlet HttpServletRequest req request HttpServletResponse res response JSPBean jspbean new JSPBean PrintWriter out String submit String getresult String getstatus String logout String appselect see javax servlet http HttpServlet void javax servlet http HttpServletRequest javax servlet http HttpServletResponse public void doGet HttpServletRequest req HttpServletResponse resp throws ServletException IOException performTask req resp
283. lt i gt getHostname lt lt lt lt i gt getCpu lt lt endl delete i for i nodes end i delete i globus module deactivate GLOBUS GRAM CLIENT MODULE Example 5 23 is a quick example that uses the broker C implementation The application takes the first argument as the number of required nodes running the Linux operating system Example 5 23 Application using GetLinuxNodes to get n nodes include string finclude vector include broker h using namespace itso broker int main int argc char argv vector lt string gt Y GetLinuxNodes Y atoi argv 1 vector lt string gt iterator i for i Y begin i Y end i cout lt lt i lt lt end Chapter 5 Getting started with development in C C 131 Executing the program in our environment results in globus m0 GLOBUS mds 6 cl itso cherokee com d2 itso dakota com al itso apache com tl itso tupi com c2 itso cherokee com dl itso dakota com Note Do not forget to modify the MDS attributes to suit your environment in broker C define GRID INFO HOST m0 define GRID INFO PORT 2135 define GRID INFO BASEDN mds vo name maya o grid 5 3 Summary 132 In this chapter we have introduced the C C programming environment for the Globus Toolkit and provided several samples for submitting jobs and searching for resources In the next chapter we will provide samples written in Java that touch most of
284. lti protocol communication However when communicating over wide area networks applications may encounter network congestion that severely impacts the performance of the application Application enablement considerations IPC There are many possible solutions for inter process communication of which MPICH G2 described above is just one However requiring inter process communication between jobs always increases the complexity of an application and when possible should be kept to a minimum However in large complex applications it often cannot be avoided In these cases understanding the IPC mechanisms that are available and minimizing the effect of failed or slowed communications can help ensure the overall success of the applications A grid portal may be constructed as a Web page interface to provide easy access to grid applications The Web user interface provides user authentication job submission job monitoring and results of the job The Web user interface and interaction of a grid portal may be provided using an application server such as the WebSphere Application Server See Figure 2 5 on page 35 Enabling Applications for Grid Computing with Globus Application Server Grid Portal Sample Application 1 Job Status Application_2 Application_1 complete Application_2 submitted Application_3 Globus API Web Browser on User Machine Grid Portal Start
285. m 10000 is parsed by using the globus url parse function globus url t parsed url if globus url parse argv 1 amp parsed url GLOBUS SUCCESS cerr lt lt invalid URL lt lt endl exit 1 h globus io handle t connection use globus io tcp register connect for asynchronous connect Here this is a blocking call globus io tcp connect parsed url host parsed url port amp io attr Chapter 7 Using Globus Toolkit for data management 175 amp connection cout lt lt parsed url host lt lt end lt lt parsed url port lt lt end globus size t n string msg Hello world secured globus io write amp connection globus byte t STR msg msg length amp n 5 cout lt lt n lt lt end h Example 7 13 globus io example server gsisocketserver C include lt iostream gt include lt globus_io h gt include lt globus_io h gt include globus_gss_assist h f EEFAAAAAARAAA AAA RARA RA AAA RA AAA KR ER KK ERK EKER KK ERE RR KK KR RK KKK ERR EERE RK ERE KEK This macro is defined for debugging reasons It checks the status of the globus calls and displays the Globus error message The t variable needs to be defined before kkkkkkxkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk define _ a t a if t GLOBUS SUCCESS cerr globus object printable to string globus error get t exit 1 f BRR RR RRR ARA AA AAA RRR ARA KK
286. machine which runs the FTP server An overview is shown in Figure 2 3 GridFTP Client GridFTP Server control globus url copy 1 transfer File File Figure 2 2 Standard file transfer Third party data transfer allows a third party to transfer files between two servers GridFTP Server 1 GridFTP Server 2 transfer File ra File control globus url copy GridFTP Client Figure 2 3 Third party file transfer Global Access to Secondary Storage GASS GASS is used to transfer files between the GRAM client and the GRAM server GASS also provides libraries and utilities for the opening closing and pre fetching of data from datasets in the Globus environment A cache management API is also provided It eliminates the need to manually log into sites transfer files and install a distributed file system For further information refer to the Globus GASS Web site http www fp globus org gass Chapter 2 Grid infrastructure considerations 27 Replica management Another Globus facility for helping with data management is replica management In certain cases especially with very large data sets it makes sense to maintain multiple replicas of all or portions of a data set that must be accessed by multiple grid jobs With replica management you can store copies of the most relevant portions of a dat
287. milar to the Globus Toolkit 2 gatekeeper The MMUFS still determines the local account in which the job should be run by using a grid mapfile as for the Globus Toolkit 2 Grid Resource Identity Mapper GRIM is a setuid program that accesses the local host credentials and from them generates a proxy for the Local Managed Job Factory Service LMJFS This proxy credential has embedded in it the user s grid identity local account name and local policy about the user LMJFS invokes a Managed Job Service MJS with the request and returns the address of the MJS to the user The user then connects to the MJS The Globus Toolkit V8 RSL language will be described in XML format even if the functionality remains similar to Globus Toolkit 2 The Managed Job Service will translate it into scheduler specific language 294 Enabling Applications for Grid Computing with Globus Example 10 1 Globus Toolkit V3 RSL example lt rsl rs lt insert GRAM RSL Namespace gt lt gram job gt lt gram executable gt lt rsl pathElement path bin 1s gt gram executable lt gram directory gt lt rsl pathElement path tmp gt lt gram directory gt lt gram arguments gt lt gram argument gt 1 lt gram argument gt lt gram argument gt a lt gram argument gt lt gram arguments lt gram job gt lt rsl rs gt Managed Job Factory portType The Managed Job Factory Service defines an OGSI WSDL interface for submitting monit
288. most common situation complexity comes into play As shown in Figure 3 3 certain jobs within the application are executable in parallel but there are interdependences between them In the example jobs B and C can be launched simultaneously but they heavily exchange data with each other Job F cannot be launched before B and C have completed whereas job E or D can be launched upon completion of B or C respectively Finally job G finally collects all output from the jobs D E and F and its termination and results then represent the completion of the grid application Loose coupling For a grid this means the need for a job flow management service to handle the synchronization of the individual results Loose coupling between the jobs avoids high inter process communication and reduces overhead in the grid Figure 3 8 Networked job flow Chapter 3 Application architecture considerations 49 For such an application you will need to do more analysis to determine how best to split the application into individual jobs maximizing parallelism It also adds more dependencies on the grid infrastructure services such as schedulers and brokers but once that infrastructure is in place the application can benefit from the flexibility and utilization of the virtualized computing environment 3 2 4 Jobs and sub jobs 50 Another approach to ease the managing of jobs within a grid application is to introduce a hierarchical system
289. mpilation to transfer the HelloServer used on the remote hosts to manage clients requests The GASS server arbitraly listens on port 20000 StartGASSServer 20000 get the hostname using the globus function globus_libc_gethostname hostname MAXHOSTNAMELEN ITSO_GRAM CLIENT does not start the module lets do it if globus module activate GLOBUS GRAM CLIENT MODULE GLOBUS SUCCESS cerr lt lt Cannot start GRAM module exit 2 h string node we use a fixed address for this simple example but nodes getNodes SLA MDS Workload in a more complex example we should get here the list of nodes where the application is supposed to run node t0 variable used in all for loops int i Here we want test the existence of the file as there is no such checking in the ITSO GLOBUS FTP CLIENT class Appendix B C C source code for examples 343 FILES fd fopen commoncpp2 1 0 8 tar gz r if fd NULL printf Error opening commoncpp2 1 0 8 tar gz file exit 2 else that fine lets go for FTP we can close fd descriptor because a new one will be opened for each ITSO GLOBUS FTP CLIENT object fclose fd never forget to activate the Globus module you want to use globus module activate GLOBUS GASS COPY MODULE ERA AAA AA AAA A AAA A AAA AR AIA ERK ERK AAA AA RA AAA AAA AIAR AIAR In this section we perform the transfer of the dynamic librar
290. mputation are either transmitted as arguments or accessible by the job be it in local or remote storage or in a file that can also be sent across the grid Chapter 3 Application architecture considerations 51 A batch job especially one with few environmental requirements in general is well suited for deployment in a grid environment 3 3 2 Standard application A grid environment can also be applicable to a standard application like spreadsheets or video rendering systems For example if extensive financial calculations on many variations of similar input parameters are to be done these could be processed on one or more nodes within the grid See the Excel Grid example in Section 12 1 and Zetagrid in Section 11 4 of Introduction to Grid Computing with Globus SG24 6895 Often such a standard application requires an installation procedure and cannot be sent over the network to run simply as a batch job However a command line interface provided can be remotely used on a grid for execution of the application where it is installed In this case the grid broker or grid portal needs to know the locations of the application and the availability of the node The locations of the applications on the grid are relatively fixed meaning in order to change it a new installation has to be performed and the application may need to be registered with the grid portal or grid server before it can be used New installations are mostly done manu
291. munication 7 Unsupported network protocols used by jobs may be prohibited to perform their tasks due to firewall rules 3 13 2 The grid application qualification scheme The application architecture considerations and requirements of grid services lead to a qualification scheme which highlights the solution requirements and criteria that impact building a grid application The scheme shown in Appendix A Grid qualification scheme on page 297 provides a summary of 35 criteria of which most will apply to any grid application but not all The criteria are to be seen in relation to each other and to the individual situation of the project The scheme is intended for use at the analysis phase of a grid application development project and allows the user to quickly detect and highlight the most critical issues for the grid application to be built It may also reveal any show stoppers or identify more effort to be planned to solve a certain problem The scheme is provided as a tool that can be modified for specific use at a given grid application project 3 14 Summary The approach to build a grid enabled application either from scratch or based on existing solutions adds a wide range of aspects for problem analysis application architecture and design This chapter has provided an overview of the issues to consider for any grid application Some of these items may not apply for every project Some aspects are familiar from other a
292. n between the EU DataGrid and the Particle Physics Data Grid Project PPDG GDMP is described in detailed in Grid Data Mirroring Package GDMP on page 97 For more information see http www eu datagrid org 4 3 2 GriPhyn The GriPhyN Project is developing grid technologies for scientific and engineering projects that must collect and analyze distributed petabyte scale data sets GriPhyN research will enable the development of Petascale Virtual Data Grids PVDGs through its Virtual Data Toolkit VDT Virtual data means that data does not necessarily have to be available in a persistent form but is created on demand and then materialized when it is requested 102 Enabling Applications for Grid Computing with Globus The Virtual Data Toolkit VDT is a set of software that supports the needs of the research groups and experiments involved in the Griphyn project It contains two types of software gt Core grid software Condor Scheduler GDMP REF and the Globus Toolkit In future releases VDT will use the NMI software gsissh kerberos GSI gateway Condor G Software developed to work with virtual data Chimera is the first software of this kind The Chimera Virtual Data System VDS provides a catalog that can be used by application environments to describe a set of application programs transformations and then track all the data files produced by executing those applications derivations Chimera contains the mecha
293. nabled MPI http www niu edu mpi Grid Application Development software GrADS http nhse2 cs rise edu grads gt IBM Grid Toolbox http www alphaworks ibm com tech gridtoolbox Grid Application Framework for Java http ww alphaworks ibm com tech GAF4J IBM Data Management products http ww ibm com software data Database Access and Integration Services Working group http www gridforum org 6 DATA dais htm MDS information provider example http www unix mcs anl gov slang mds iprovider example OpenSSH http www openssh org gt NFS Version 4 Open Source Reference Implementation http ww citi umich edu projects nfsv4 gt Avaki http ww avaki com 370 Enabling Applications for Grid Computing with Globus Global File System http www sistina com products_gfs htm Replica Location Service http www globus org rls Replica Location Service http www globus org rls GDMP http project gdmp web cern ch project gdmp OGSA DAI http umbriel dcs gla ac uk NeSC general projects 0GSA_DAI gSOAP http www cs fsu edu engelen soap htm Spitfire project http spitfire web cern ch Spitfire Storage Resource Broker http www npaci edu DICE SRB European Union data grid http www eu datagrid org Griphyn Project http www griphyn org Particle Physics Data Grid http www ppdg net Grid Portal Development Kit http doesciencegrid org projects GPDK GSI OpenSSH http www nsf middleware o
294. name TMP HOSTNAME gsissh Nodes i d TMP mkdir TMP amp All file copies and remote execution use the TMP variable in their relative path name to refer to the remote files This way each client machine can submit a job without conflicting with another client gsissh Nodes i chmod x TMP GenerateDraws amp ProcessID i gsiscp GenerateDraws Nodes i TMP amp ProcessID i For more granularity TMP could also use the process ID of the Submit script TMP HOSTNAME Shell script callback As we cannot use a callback mechanism in a shell script We start each command in the background Therefore they become non blocking operations and all commands can be submitted simultaneously gsiscp GenerateDraws Nodes i TMP amp gsissh Nodes i chmod x TMP GenerateDraws amp 250 Enabling Applications for Grid Computing with Globus The wait command is used to wait for their completion and acts like a simple callback wait ProcessID i Job submission GenerateDraws needs to be copied to each execution node Each execution node must have the GSIssh server up and running gsiscp is used to transfer the files and gsissh is used to remotely execute the chmod x command as shown in Example 9 2 Example 9 2 Job submission using gsissh for i in 1oop do gsiscp GenerateDraws Nodes i TMP amp ProcessID i done for i in 1oop do wait ProcessID
295. nd how a job and its related data might flow through the grid In this chapter we discuss various components and services in more detail and highlight specific issues and considerations that you should be aware of as you architect and develop your grid application Copyright IBM Corp 2003 All rights reserved 13 2 1 Grid infrastructure components This section describes the grid infrastructure components and how they map with the Globus Toolkit It will also address how each of the components can affect the application architecture design and deployment The main components of a grid infrastructure are security resource management information services and data management Security is an important consideration in grid computing Each grid resource may have different security policies that need to be complied with A single sign on authentication method is a necessity A commonly agreed upon method of negotiating authorization is also needed When a job is submitted the grid resource manager is concerned with assigning a resource to the job monitoring its status and returning its results For the grid resource manager to make informed decisions on resource assignments the grid resource manager needs to know what grid resources are available and their capacities and current utilization This knowledge about the grid resources is maintained and provided by Grid Information Service GIS also known as the Monitoring and Discov
296. nd the job that handles the splitting dynamically when the job is submitted and retrieves the individual data sets after each job has completed The second aspect of data management is during the job execution by itself The job needs to access data that may not be available on local storage Several solutions are available gt Data is stored on network accessible devices and jobs work on the data through the network Copyright IBM Corp 2003 All rights reserved 71 Data is transferred to the execution node before the job is executed such that the job can access the data locally 72 Enabling Applications for Grid Computing with Globus 4 1 Data criteria Any application at its core is processing data This means that we must take a closer look at data being used for and within a grid application The following sections cover criteria related to handling data when deciding whether an application is a good candidate for a grid Data influences many aspects of application design and deployment and determines whether a planned grid application can provide the expected benefits over any other data solution As the grid can be dynamically set up and changed there are some special data related considerations The following sections describe several considerations related to data in the grid such as the distribution and location of data in regard to accessing jobs and when and how data is created and consumed by jobs 4 1 1 Indiv
297. ndencies or requirements specific to the operating system the application needs to verify that the correct environment is available and handle issues related to the differing environments Output file formats The knowledge of the output file format is necessary when the output of an application running on one grid host is accessed by another application running on a different grid host The two grid hosts may have different platform environments XML may be considered as the data exchange format XML has now become popular not only as a markup language for data exchange but also as a data format for semi structured data 2 3 Summary The functional components of a grid environment as well as non functional considerations such as performance requirements or operating system requirements must be well understood when considering enabling an application to execute in a grid environment This chapter has touched on many of these considerations In the next chapter we look at the properties of an application itself to determine whether it is a good candidate to be grid enabled Chapter 2 Grid infrastructure considerations 41 42 Enabling Applications for Grid Computing with Globus Application architecture considerations In the previous chapters we have introduced grid computing the Globus Toolkit and its components and some of the considerations that the infrastructure can impose on a grid enabled application In this chapter we lo
298. ng point to determine the suitability of a grid environment for an application The criteria are intended to address the two main aspects of architecture functional and operational as identified in the article A standard for architecture description see bibliography Note Please note that this is not an exhaustive list but rather presents a summary from the considerations presented in the earlier chapters of this publication The reader is urged to take into account the specifics of the people process and technologies being considered and to recognize that a full evaluation may require evaluation of a combination of these criteria rather than considering each criteria in isolation Copyright IBM Corp 2003 All rights reserved 297 A suggested grid application qualification scheme The architecture considerations for a grid application lead to a qualification scheme that highlights the solution requirements and criteria that impact building a grid application Table A 1 on page 299 lists several criteria to consider when evaluating an application for grid enabling and deployment For each criterion in the table the following are shown Range Provides a summary of the possible values for the criterion Importance A weight factor that provides a subjective assessment of how important the criterion is for the application under assessment Effort A weight factor that assesses how much effort would be required to mod
299. ng the GramJob with the RSL GramJob job new GramJob rs1 job addListener this Pinging resource contact to check if we are allowed to use it try Gram ping rmc catch Exception e System out print ln Ping Failed e getMessage System out printIn Requesting Job try job request rmc catch Exception e System out println Error e getMessage job removeListener this public static void main String args GRAMTest run new GRAMTest run runJob System out print n All Done MDS gives users the ability to obtain vital information about the grid and grid resources It utilizes LDAP to execute queries Users can retrieve this information by using the grid info search command line tool The JavaCog Kit Version 1 1a provides a Java version of grid info search that does not use MDS Because the MDS class itself is deprecated users should use JNDI with LDAP or the Netscape Directory SDK to access MDS functions with the JavaCog 140 Enabling Applications for Grid Computing with Globus 6 4 1 Example of accessing MDS Example 6 8 is a condensed version of the GridInfoSearch class provided in the org globus tools package for the JavaCog Kit Version 1 1a The MyGridInfoSearch class uses GSI authentication It uses JNDI to connect to the LDAP server and searches for the object class specified by a variable It is important to note that when using this MyGridProxylnit class tha
300. nilo re mE ne SEE Tue Done Your proxy is valid until Thu Feb 27 06 19 17 2003 The option pwstdin permits us to create a proxy without being prompted for a password This way the proxy creation can be integrated in the Submit script if needed You also need to compile the GenerateDraws C program and be sure that the GSIssh server is up and running in all nodes See Installation on page 211 for more information Note When connecting to a host for the first time ssh needs to retrieve its public host key To bypass this request you can add the following option to the configuration file GLOBUS_LOCATION etc ssh ssh_config StrictHostKeyChecking no Let us perform the test on six numbers instead of eight to have a better chance to win globus m0 other Submit 1 4 10 15 20 34 The number of draws tested is 100000 Transferring executable files GenerateDraws 1005 FEROCIA OR e e k e e e de 52775 00 00 GenerateDraws 100 e e e e e e R AE e e e e e e k Ae e e e e e E e de 52775 00 00 252 Enabling Applications for Grid Computing with Globus GenerateDraws 100 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 52775 GenerateDraws 100 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 52775 GenerateDraws 100 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 52775 GenerateDraws 100 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 52775 GenerateDraws 100 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 52775 GenerateDraws 100 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 52775 GenerateDraws 100 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk 5
301. nism to locate the recipe to produce a given logical file in the form of an abstract program execution graph These abstract graphs are then turned into an executable DAG for the Condor DAGman meta scheduler by the Pegasus planner which is bundled into the VDS code release For more information check the following Web site http www griphyn org 4 3 3 Particle Physics Data Grid The Particle Physics Data Grid collaboration was formed in 1999 The purpose of this long term project is to provide a data grid solution supporting the data intensive requirements of particle and nuclear physics PPDG is actively participating in the International Virtual Data Grid Laboratory IVDGL http www ivdgl org together with GriPhyN as a three prong approach to data grids for US physics experiments PPDG focuses on file replication and job scheduling Also it is working closely with complementary data grid initiatives in Europe and beyond Global Grid Forum European DataGrid and as part of the HENP For example the Grid Data Mirroring Package has been a mutual effort of EU DataGrid and PPDG For more information check the following Web site http www ppdg net 4 4 Summary A grid application must carefully take into account the topology of the data that will be processed during the job execution Data can be centralized or distributed across the execution nodes A mixed solution is usually the most appropriate and it highly depends on the
302. nitialized by using globus ftp client handleattr init By using these two handles a client can easily execute all of the usual FTP commands Chapter 7 Using Globus Toolkit for data management 195 gt globus ftp client put globus ftp client get globus ftp client mkdir globus ftp client rmdir globus ftp client list globus ftp client delete globus ftp client verbose list globus ftp client move gt globus ftp client exists tests the existence of a file of a directory gt globus ftp client modification time returns the modification time of a file gt globus ftp client size returns the size of the file The globus ftp client get functions only start a get file transfer from an FTP server If this function returne GLOBUS SUCCESS then the user may immediately begin calling globus ftp client read to retrieve the data associated with this URL Similarly the globus ftp client put functions only start a put file transfer from an FTP server If this function returns GLOBUS SUCCESS then the user may immediately begin calling globus ftp client write to write the data associated with this URL Example 7 22 First example extracted from the Globus tutorial f Fk RR RRR KERR EKER ERK KK RR KK RRR KKK KK RK KEK EKER ERK KK RK KR KKK ERK ERK ER EK KE Globus Developers Tutorial GridFTP Example Simple Authenticated Put There are no handle or operation attributes used in this example This means
303. nt in order to fit into the OGSA framework The OGSA architecture and OGSI infrastructure provides a common framework for grid services so developing new OGSI compliant services or specialized versions of existing services is quite straightforward Every OGSI compliant service can be used and managed via common interfaces so building systems and applications with OGSI compliant services is much easier OGSI software provides mandatory Grid service features such as service invocation lifetime management a service data interface and security interfaces that ensure a fundamental level of interoperability among all grid services Chapter 10 Globus Toolkit V3 0 291 10 3 Open Grid Service Architecture OSGA 292 OGSA draws on the same infrastructure as used in Web services XML SOAP WSDL and WSIL However there are some important conceptual and practical extensions that arise from the need to address a dynamic grid environment providing mechanisms to create and discover customized service instances with controlled fault resilient and secure management of distributed atomic or collective services often with a long lived state Four important concepts in OGSA are Naming Each grid service instance is globally uniquely and for all time named by a Grid Service Handle GSH gt Factories Create new grid service instances and maintain a group of service data elements that can be queried Factories play the role of a g
304. o bus GenerateDrawsGlobus m0 itso maya com file clean up GenerateDrawsGlobus m0 itso maya com environment LD LIBRARY PATH GLOBUS LOCATION lib G GASS servers on the execution nodes A GASS server is started on all execution nodes We use globusrun to start this server The command globusrun is submitted in the background so that it is non blocking in the script The URL of the GASS server is written in the file gass server in the current directory where is an index used in the script to refer to the execution nodes Example 9 5 Starting a remote GASS server using globusrun for i in loop Chapter 9 Application examples 257 do rsl amp executable GLOBUS LOCATION bin globus gass server arguments c t r environment LD LIBRARY PATH GLOBUS LOCATION lib file clean up Monitor TMP globusrun o r Nodes i rs1 gt gass server i amp done As the GASS server is not started immediately we test the size of the file gass server before trying to communicate with this server This size will actually remain null as long as the GASS server started remotely and has not returned the URL on which it will listen if s gass server i then contact cat gass server i globus url copy contact Monitor TMP file PWD Monitor i status cat Monitor i statussum status statussum echo Nodes i Monitor cat Monitor i fi Finally the GASS servers are shut down at the end o
305. o run shell scripts or to interactively issue shell commands but it also permits the transfer of files between systems without being prompted for a password and a user ID GSlssh installs the following tools in GLOBUS_LOCATION bin gt gsisshis used to either securely connect to a remote host or to securely execute a program on a remote host gt gsiscp is used to securely copy files or directories onto a remote host gt sftp is used to securely copy files or directories onto a remote host sftp is not related to gsiftp It is a different protocol that provides encryption and the same commands as the FTP protocol gsiscp and sftp do not perform as well as GridFTP but they can easily be used in a shell script to transfer files from one location to another Note Be careful to use host names for which certificates have been issued otherwise you will get the following kind of error messages if you try to use the IP address instead of the host name 21569 gss init context failed 0 Grid 0 Globus CN host g3 itso guarani com in the context and the target name CN host 192 168 0 203 The purpose of this example is to simulate a large number of draws of a lottery and to check if a winning combination was drawn Each draw consists of eight numbers between one and 60 inclusive 246 Enabling Applications for Grid Computing with Globus The program GenerateDraws whose source code GenerateDraws C is available in Lottery example
306. oFrontEnd C ticket getTicket time IP address SLA in a real production case ticket random node getNodes SLA MDS Workload Application Type in a real production case Chapter 9 Application examples 285 node t0 ITSO GRAM JOB job2 cout lt lt start app server on lt lt node lt lt endl rsl req amp executable https rs req hostname rs req 20000 rsl req get current dir name rsl req HelloServer environment LD LIBRARY PATH HOME tmp lib count 1 arguments char tmpstr 20 sprintf tmpstr Zld ticket rs req tmpstr rs req node rs req submit it to the GRAM cout lt lt rs req lt lt end job2 Submit node rsl req job2 Wait 9 3 4 Compilation All programs HelloServer C HelloClient C and HelloFrontEnd C use the class provided by the GNU Common C library thread sockets management They are not covered in this publication and are only used to quickly develop the examples Consequently the header files located in usr local include cc 2 and the libraries Iccgnu2 Ipthread dl must be used during the compilation phase The library is a prerequisite to run these examples 1 First use gl obus make header to generate a file globus header in which variables are set to appropriate values globus header will be included in the Makefile globus makefile header flavor gcc32 globus io globus gss as
307. obs in a round robin fashion to the next machine matching the resource requirements However there are advantages to using a more advanced scheduler Some schedulers implement a job priority system This is sometimes done by using several job queues each with a different priority As grid machines become available to execute jobs the jobs are taken from the highest priority queues first Policies of various kinds are also implemented using schedulers Policies can include various kinds of constraints on jobs users and resources For example there may be a policy that restricts grid jobs from executing at certain times of the day Schedulers usually react to the immediate grid load They use measurement information about the current utilization of machines to determine which ones are not busy before submitting a job Schedulers can be organized in a hierarchy For example a meta scheduler may submit a job to a cluster scheduler or other lower level scheduler rather than to an individual machine More advanced schedulers will monitor the progress of scheduled jobs managing the overall work flow If the jobs are lost due to system or network outages a good scheduler will automatically resubmit the job elsewhere However if a job appears to be in an infinite loop and reaches a maximum timeout then such jobs should not be rescheduled Typically jobs have different kinds of completion codes some of which are suitable for resubmission and some o
308. ock done GLOBUS TRUE globus cond signal amp cond globus mutex unlock amp lock return ERA AAA AAA ARA AAA AA AAA AAA AAA KK ERK KK ARA ARR RA AR AAA AAA AAA KERR KER KR ERR EERE RK data cb A pointer to this function is passed to the call to globus ftp client register write It is called when the user supplied buffer has been successfully transferred to the kernel Note that does not mean it has been successfully transmitted In this simple version it justs reads the next block of data and calls register write again KRK KKK KKK KEK KKK KKK ERR EERE KEKE KEKE RK EKER EKER KK KER KERR KEKE RERERERE static void data cb void User arg globus ftp client handle t handle globus object t err globus byte t buffer globus size t length globus off t offset globus bool t eof if err fprintf stderr 5s globus object printable to string err else Chapter 7 Using Globus Toolkit for data management 197 if eof FILE fd FILE user arg int rc rc fread buffer 1 MAX BUFFER SIZE fd if ferror fd SUCCESS printf Read error in function data cb errno d n errno return globus ftp client register write handle buffer rc offset length feof fd SUCCESS data cb void fd if eof else return data cb Fei kek k kek k ke kk ke k keke keke k k ke Main Program KEKKKAAAKAKAKAKAKKAKAKA
309. ode ListRs Node RSLParser parse ListRs Node class myrslstring2 Chapter 6 Programming examples for Globus using Java 147 catch Exception e System out print n Cannot parse rs string nv node removeParam arguments vals nv getValues System out println Removing nv System out println Your string with the arguemnts removed node catch Exception e System out println Cannot parse rs string Example 6 17 on page 147 stores an RSL string as a ListRsINode and removes the argument attribute from the string The removeParam method removes the arguments attribute and all of its variables 6 6 GridFTP The JavaCoG Kit provides the org globus ftp package to perform FTP and GridFTP operations It is basically an implementation of the FTP and GridFTP protocol The FTP client provides the following functionality Client server FTP file transfer Third party file transfer Passive and active operation modes ASCII IMAGE data types Stream transmission mode YYYY Y The GridFTP client extends the FTP client by providing the following additional capabilities Extended block mode Parallel transfers Striped transfers Restart markers Performance markers vvvvy Packages The following packages are available to be used with the Java CoG gt org globus ftp classes for direct use 148 Enabling Applications for Grid Computing with Globus org globus ftp vanilla Vanilla FTP protocol
310. odel ize Nei buque uM Pep RE us 279 Grid model 322 arce ne io era 280 Hello World example with dynamic library dependencies issues 281 Globus Toolkit V3 job invocation LL 294 Enabling Applications for Grid Computing with Globus Notices This information was developed for products and services offered in the U S A IBM may not offer the products services or features discussed in this document in other countries Consult your local IBM representative for information on the products and services currently available in your area Any reference to an IBM product program or service is not intended to state or imply that only that IBM product program or service may be used Any functionally equivalent product program or service that does not infringe any IBM intellectual property right may be used instead However it is the user s responsibility to evaluate and verify the operation of any non IBM product program or service IBM may have patents or pending patent applications covering subject matter described in this document The furnishing of this document does not give you any license to these patents You can send license inquiries in writing to IBM Director of Licensing IBM Corporation North Castle Drive Armonk NY 10504 1785 U S A The following paragraph does not apply to the United Kingdom or any other country where such provisions are inconsistent with local law INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES
311. of sub jobs A job could utilize the services of the grid environment to launch one or more sub jobs For this kind of environment an application would be partitioned and designed in such a way that the higher level jobs could include the logic to obtain resources and launch sub jobs in whatever way is most optimal for the task at hand This may provide some benefits for very large applications to isolate and pass the control and management of certain tasks to the individual components Figure 3 4 Job with sub jobs in a grid application As illustrated in Figure 3 4 in the shaded area named X job A launches sub jobs B and C which communicate with each other and will launch another sub job F For the grid application everything within the shaded area X may be regarded as one job identified by job A In this case the grid server or grid portal has to be Enabling Applications for Grid Computing with Globus notified of either completion of the whole task under X in order to launch D and E respectively or an explicit communication is established to handle notifications about partial completion of the tasks identified within job A by its sub jobs B and C in order to run jobs E and D respectively on their own schedules In the latter case the grid services can take advantage of the available resources and gain the freedom to more efficiently distribute the workload On the other hand it generates more management requirements for
312. oid invalidSelection Something was wrong with the client input try RequestDispatcher rd getServletContext getRequestDispatcher invalidSelection html rd forward req res catch javax servlet ServletException e 228 Enabling Applications for Grid Computing with Globus System out printIn e catch java io IOException e System out printIn e private void invalidInput Something was wrong with the client input try RequestDispatcher rd getServletContext getRequestDispatcher invalidInput html rd forward req res catch javax servlet ServletException e System out printiIn e catch java io IOException e System out print n e private void sendResult String list int size list length for int i 0 i lt size i String s list i out printIn s lt br gt System out print n s s trace end for From the welcome screen the user may also request application status application results and logout Figure 8 6 on page 230 shows the flow When the user clicks My Application Status My Application Results or Logout the Application Servlet is called Chapter 8 Developing a portal 229 doPost welcome html login html Figure 8 6 Simple grid portal application information and logout flow Tip Determine which button is pressed from welcome html TD width 20 gt lt INPUT type submit name status
313. ok at the characteristics of applications themselves We provide guidance for deciding whether a particular application is well suited to run on a grid Often we find people assuming that for an application to gain advantage from a grid environment it must be highly parallel or otherwise able to take advantage of parallel processing In fact some like to think of a grid as a distributed cluster Although such parallel applications certainly can take advantage of a grid you should not dismiss the use of grids for other types of applications as well As introduced in Chapter 1 Introduction on page 1 a grid can be thought of as a virtual computing resource Even a single threaded batch job could benefit from a grid environment by being able to run on any of a set of systems in the grid taking advantage of unused cycles A grid environment that can be used to execute any of a variety of jobs across multiple resources transparently to the user provides greater availability reliability and cost efficiencies than may exist with dedicated servers Copyright IBM Corp 2003 All rights reserved 43 Similarly the need for large amounts of data storage can also benefit from a grid Examples include thoroughly analyzing credit data for fraud detection bankruptcy warning mechanisms or usage patterns of credit cards Operations on vast amounts of data by uniform calculations such as the search for identifiable sequences in the human genome dat
314. ommands string rs req ITSO GRAM JOB job cout lt lt library compilation on lt lt node lt lt endl rsl req amp executable https rs req hostname rs req 20000 rs req get current dir name rs req Compile count 1 submit it to the GRAM cout lt lt rs req lt lt endl job Submit node rsl req job Wait f BRRRR RRR RRR AAA AA AAA AAA he e e e AR ARA AAA KEKE KEKE KER AIA RK KE AAA ticket getTicket time IP address SLA ina real production case ticket random node getNodes SLA MDS Workload Application Type in a real production case node t0 9 3 3 Starting the application by the resource provider The front end server also submits another job to start HelloServer on the application server HelloServer listens on port 4097 and uses the ticket to authenticate the connection In the example the ticket is fixed at the application startup but for a real production environment other parameters like time IP address public private keys and so on may be taken into account to securely authenticate a connection from a client The server is arbitrarily started on node t0 Other parameters like MDS information service level agreements with the customer workload resources provider agreements and such can be used here to determine where the application should be started Example 9 16 Front end server starts the HelloServer on remote node Hell
315. on data encryption and so on The Grid Security Infrastructure GSI component of the Globus Toolkit provides robust security mechanisms The GSI includes an OpenSSL implementation It also provides a single sign on mechanism so once a user is authenticated a proxy certificate is created and used when performing actions within the grid When designing your grid environment you may use the GSI sign in to grant access to the portal or you may have your own security for the portal The portal would then be responsible for signing into the grid either using the user s credentials or using a generic set of credentials for all authorized users of the portal Chapter 1 Introduction 7 Ti m Virtual Computing Resource ie Figure 1 2 Security in a grid environment 1 3 3 Broker Once authenticated the user will be launching an application Based on the application and possibly on other parameters provided by the user the next step is to identify the available and appropriate resources to utilize within the grid This task could be carried out by a broker function Though there is no broker implementation provided by Globus there is an LDAP based information service This service is called Grid Information Service GIS or more commonly the Monitoring and Discovery Service MDS This service provides information about the ava
316. on files In order to add your own resource to be used by MDS you must create specific information providers to transfer the properties and status to GRIS MDS client The MDS client is based on the LDAP client command 1dapsearch or an equivalent API A search for information about resources in the grid environment is initially performed by the MDS client Application enablement considerations Information Services Considerations related to information services include gt It is important to fully understand the requirements for a specific job so that the MDS query can be correctly formatted to return resources that are appropriate gt Ensure that the proper information is in MDS There is a large amount of data about the resources within the grid that is available by default within the MDS However if your application requires special resources or information that is not there by default you may need to write your own information providers and add the appropriate fields to the schema This may allow your application or broker to query for the existence of the particular resource requirement MDS can be accessed anonymously or through a GSI authenticated proxy Application developers will need to ensure that they pass an authenticated proxy if required Your grid environment may have multiple levels of GIIS Depending on the complexity of the environment and its topology you want to ensure that you are accessing an appropr
317. on page 349 is used to generate random draws It takes one argument the number of draws that it needs to simulate 1000000 for example This program is executed on n nodes by using the GSlssh tools globus m0 other GenerateDraws 10 3 29 33 39 41 46 54 55 36 7 10 16 22 35 50 0 26 36 47 48 49 22 26 36 50 57 28 32 40 51 55 24 45 49 60 20 39 50 59 60 29 49 52 57 9 36 43 52 58 8 20 22 27 45 FM CO tO GenerateDraws also creates a file named Monitor on the execution node This file is copied to the submission nodes every five seconds Monitor contains the percentage of random draws completed and permits the monitoring of the whole application node 1 Monitor node 2 q Submit 1 2 20 31 12 23 Monitor MOR peene ll gr ders Monitor 2 fe Monitor n te Figure 9 1 Lottery example Chapter 9 Application examples 247 The Submit script is used to submit the jobs to the grid We use the grep command to check the output of the GenerateDraws program and to detect if the draw we played is a winner Example 9 1 Submit script the script takes the tested draw as a parameter fexample Submit 3 4 5 32 34 43 n 100000 NodesNumber 10 temporary working directory on the execution nodes TMP HOSTNAME i 0 the loop variable is used is all the for loops the format is 12 3 4 n oop use here the bro
318. ong size client getSize remoteFileName DataSink sink null sink new FileRandomIO new java io RandomAccessFile localFileName rw setting FTPClient to active so be able to send file client setLocalPassive client setActive client extendedGet remoteFileName size sink null If performance or progress monitoring is required it can be easily implemented using the MarkerListener interface See the JavaCoG API description for more information Example 6 27 GridFTP client server example 6 of 6 public static void main String args try Initialize GridFTPclient gftp new GridFTPclient get credentials System out print ln Getting Credentials gftp getCredentials get ftp client System out println Creating the FTP Client gftp createFTPClient dl itso dakota com perform client to server copy System out println Tranfering Client to Server gftp ClientToServer tmp d2 to d1 tmp d2 to d1 Chapter 6 Programming examples for Globus using Java 153 perform server to client copy System out print ln Transfering Server to Client gftp ServerToClient tmp dl to d2 tmp dl to d2 System out print n All Done catch Exception e System out println Error e getMessage 6 6 3 URLCopy The URLCopy class provides a very easy way of transferring files It understands the GSIFTP GASS FTP and FILE protocol Example 6 28 URLCopy example 1 of 2 packa
319. ons for enabling applications as discussed throughout the rest of the book 1 3 1 Portal User interface Just as a consumer sees the power grid as a receptacle in the wall likewise a grid user should not see all of the complexities of the computing grid Though the user interface could come in many forms and be application specific for the purposes of our discussion let us think of it as a portal Most users today 6 Enabling Applications for Grid Computing with Globus understand the concept of a Web portal where their browser provides a single interface to access a wide variety of information sources A grid portal provides the interface for a user to launch applications that will utilize the resources and services provided by the grid From this perspective the user sees the grid as a virtual computing resource just as the consumer of power sees the receptacle as an interface to a virtual generator XT WIR Virtual Computing C Portal Resource Figure 1 1 Possible user view of grid The current Globus Toolkit does not provide any services or tools to generate a portal but this can be accomplished with tools such as WebSphere 1 3 2 Security A major requirement for grid computing is security At the base of any grid environment there must be mechanisms to provide security including authentication authorizati
320. onsidered in both of the load balancing models The non operational grid resources need to be detected and no new work should be sent to failed resources in the push model In addition all the submitted jobs that did not complete need to be taken care of in both push and pull models All the uncompleted jobs in the failed host need to be either redistributed or taken over by other operational hosts in the group This may be accomplished in one of two ways In the simplest the uncompleted jobs can be resent to another operational grid resource in the push model or simply added back to the job queue in the pull model In a more sophisticated approach multiple grid resources may share job information such as the jobs in the queue and checkpoint information related to running jobs as shown in Figure 2 4 In both models the operational grid resources can take over the uncompleted jobs of a failed grid resource job checkpoint data job checkpoint data job checkpoint data job checkpoint data Figure 2 4 Share job information for fault tolerance Application enablement considerations Load balancing When enabling applications for a grid environment design issues related to load balancing may need to be considered Based on the load balancing mechanism that is in place manual push pull or some hybrid combination the application designer developer needs to understand how this will affect the application and Enab
321. oot 1 0 0 Feb26 00 00 04 init root 2 1 0 Feb26 00 00 00 keventd root 2 1 0 Feb26 00 00 00 keventd root 3 1 0 Feb26 00 00 00 kapmd root 4 1 0 Feb26 00 00 00 ksoftirqd CPUO root 5 1 0 Feb26 00 00 09 kswapd root 6 1 0 Feb26 00 00 00 bdflush root 7 1 0 Feb26 00 00 01 kupdated root 8 1 0 Feb26 00 00 00 mdrecoveryd Enabling Applications for Grid Computing with Globus root 12 1 0 Feb26 00 00 20 kjournald root 91 1 0 Feb26 00 00 00 khubd root 196 1 0 Feb26 00 00 00 kjournald t3user t3 guser Although there is no way to directly run RSL scripts with the globus job run command the command utilizes RSL to execute jobs By using the dumprsl parameter globus job run is a useful tool to build and understand RSL scripts Example 2 3 Using globus job run dumprsl to generate RSL t3user t3 guser globus job run dumprs l t3 tmp MyScript amp executable tmp MyTest t3user t3 guesr Gatekeeper The gatekeeper daemon provides a secure communication mechanism between clients and servers The gatekeeper daemon is similar to the inetd daemon in terms of functionality However the gatekeeper utilizes the security infrastructure GSI to authenticate the user before launching the job After authentication the gatekeeper initiates a job manager to launch the actual job and delegates the authority to communicate with the client Job manager The job manager is created by the gatekeeper daemon
322. opology graph helps to identify needs for data splitting and replication 4 1 9 Data types When considering writing jobs for a grid application that could run on any system anywhere in the world the question of data types code pages and trans coding arises For example when transferring a C source file containing the following statement written by a German programmer as argv 1 0 It may appear as e argvEl 00 On a Danish system or as amp argv 1 0 On an American system where the compiler would not understand it Therefore one should be aware of and take into account the type of data its representation format and standards for data exchange To name a few of the standards and variations that might be used or have to be considered within the application ASCII vs EBCDIC Single byte vs double byte character sets Unicode UTF 8 16 32 Big endian vs little endian APIs and standards for data exchange SOAP MQ SQL HTML XML J2EE JDBC And more YYYY Y Chapter 4 Data management considerations 79 gt Different multi media formats for Images Animation Sound Fonts Archives And more Measurement units Metric vs non metric Currencies And more 4 1 10 Data volume and grid scalability The ability for a grid job to access the data it needs will affect the performance of the application When the data involved is either
323. or examples 345 346 BroadcastAddress addr addr localhost cout lt lt binding for lt lt addr getHostname lt lt lt lt 4096 lt lt end GridApp server addr while server isPendingConnection 300000 the server runs for a limited period of time tcp new GridAppSession server tcp gt detach the new thread is daemonize to manage the client connection h Stop the GASS server when exiting the program StopGASSServer HelloServer C finclude lt cc socket h gt include lt cstdlib gt ifdef CCXX NAMESPACES using namespace std using namespace ost fendif class GridApp public TCPSocket public GridApp InetAddress amp ia void end h GridApp GridApp InetAddress amp ia TCPSocket ia 4097 void GridApp end endSocket int main int argc char argv tcpstream tcp long ticket ticket atol argv 1 InetAddress addr Enabling Applications for Grid Computing with Globus addr argv 2 cout lt lt addr lt lt addr lt lt lt lt 4097 lt lt end GridApp server addr long i daemonize long 1 fork if 1 gt 0 exit 0 parent exits here while server isPendingConnection 300000 tcp open server if tcp isPending Socket pendingInput 2000 tcp gt gt i cout lt lt user entered lt lt i lt lt ticket lt lt end if i ticket tcp lt lt Bad ticket lt lt
324. oring and controlling a job It is used by a GRAM client to submit a job The CreateService operation of the Managed Job Factory portType prepares a job for submission It takes as input parameter RSL xml document specifying the job to be run and returns the Grid Service Reference GSR to MJS as an output parameter that is a WSDL definition of the MJS instance The Service Data Element of the Managed Job Factory portType lists the GSHs of MJS instances Managed Job portType The Start operation submits a job The MJS will clean up everything when the job is destroyed It cleans up directories files Gass cache and so on The Service Data Elements include gt Job status gt GSH to File Stream Factory Service for job s stdout gt GSH to File Stream Factory Service for job s stderr File Stream Factory portType The CreateService operation prepares to stream a job s stdout or stderr to a destination URL The input parameter is the destination URL and the output parameter returns the GSH Chapter 10 Globus Toolkit V3 0 295 The StartStreaming operation starts the streaming to the destination URL GRAM Client Interface Both a C and Java API will be provided in the Globus Toolkit V3 to communicate with the Master Job Service An API translator will be also provided in the Globus Toolkit V3 for the Globus C API the Java and Python Cog Kit that will translate the Globus Toolkit 2 RSL format into the Globus Toolkit V3
325. ovides the output result by itself Figure 4 3 on page 81 illustrates this case 80 Enabling Applications for Grid Computing with Globus pre processing 6S 6S NANNA NANNA post processing Figure 4 8 Independently working jobs on disjunct data subsets This specific case can be easily integrated in a Globus grid environment The scalability of such a solution depends on the following criteria gt Time required to transfer input data Processing time to prepare input data and generate the final data result In this case the input data may be transported to the individual nodes on which its corresponding job is to be run Preloading of the data might be possible depending on other criteria like timeliness of data or amount of the separated data subsets in relation to the network bandwidth Static input files Static input files is the other case that may be suited to using an application on a grid Figure 4 4 on page 82 illustrates how in this case each job repeatedly works on the same static input data but with different parameters over a long period of time Chapter 4 Data management considerations 81 Figure 4 4 Static input data processed by jobs with changing parameters In this case the job can work on the same static input data several t
326. peedMHz attributes respectively The broker multiplies the three attributes and performs a quick sort to return the nodes that apparently are the best available Each node is checked with the function globus gram client ping to check if the node is available The complete source code is available in Broker C on page 327 Chapter 5 Getting started with development in C C 127 We use the LDAP API provided by the Globus Toolkit 2 2 to send the request to the main GIIS server located on mO in our lab environment The definition is statically defined in the program but can be easily provided as a parameter to the GetLinuxNodes function if needed define GRID INFO HOST m0 define GRID INFO PORT 2135 define GRID INFO BASEDN mds vo name maya o grid In the function GetLinuxNodes the connection with MDS is managed by a structure of type LDAP initialized by the two calls Idap open and ldap simple bind s for the connection Example 5 18 LDAP connection char server GRID INFO HOST int port 7 atoi GRID INFO PORT char base dn GRID INFO BASEDN LDAP ldap server Open connection to LDAP server if Idap server 1dap open server port GLOBUS NULL ldap perror ldap server ldap open exit 1 Bind to LDAP server if 1dap simple bind s ldap server LDAP SUCCESS ldap perror ldap server ldap simple bind s ldap unbind ldap server exit 1 We are onl
327. plete Instead the Globus call returns immediately The callback will be invoked after the call in a different thread Consequently a synchronization mechanism needs to be used between the callback thread and the program thread that called the asynchronous call so that the program knows when the callback has been made To ensure thread safety for the application a mutex coupled with a condition variable must be used for synchronization The condition variable is used to send a signal from the callback function to the main program and the mutex is used Chapter 5 Getting started with development in C C 109 jointly with the condition variable to avoid deadlocks between the waiting thread and the active thread gt The thread in the main program that calls the asynchronous globus function must call the following globus thread functions to wait for the completion of the operation globus mutex lock amp mutex while done GLOBUS FALSE globus cond wait amp cond amp mutex globus mutex unlock amp mutex In this code done is a boolean variable initialized to false or GLOBUS FALSE done indicates the state of the operation gt The callback function must call globus mutex lock amp mutex done GLOBUS TRUE globus cond signal amp cond globus mutex unlock amp mutex This mechanism is implemented in this publication via the ITSO CB class that embeds the done variable as an attribute ITSO_CB ITSO CB on page 315
328. pletions and failures and maintains the Globus credentials that may expire during the job execution In addition Condor G is fault tolerant The jobs submitted to Condor G and the information about them are kept in persistent storage to allow the submission machine to be rebooted without losing the job or the job information Condor G provides exactly once execution semantics Condor G detects and intelligently handles cases such as the remote grid resource crashing Condor makes use of Globus infrastructure components such as authentication remote program execution and data transfer to utilize the grid resources By using the Globus protocols the Condor system can access resources at multiple remote sites Condor G uses the GRAM protocol for job submission and local GASS servers for file transfer Application enablement considerations Scheduler When considering enabling an application for a grid environment there are several considerations related to scheduling Some of these considerations include Data management Ensuring data is available when the job is scheduled to run If data needs to be moved to the execution node then data movement may also need to be scheduled Communication Any inter process communication between related jobs will require that the jobs are scheduled to run concurrently 30 Enabling Applications for Grid Computing with Globus gt Scheduler s domain In an environment with multiple schedulers
329. plex as a sophisticated spreadsheet script or any multidimensional mathematical formula of which each requires intense computing 3 2 2 Serial flow In contrast to the parallel flow is the serial application flow In this case there is a single thread of job execution where each of the subsequent jobs has to wait for Chapter 3 Application architecture considerations 47 48 its predecessor to end and deliver output data as input to the next job This means any job is a consumer of its predecessor the data producer In this case the advantages of running in a grid environment are not based on access to multiple systems in parallel but rather on the ability to use any of several appropriate and available resources Note that each job does not necessarily have to run on the same resource so if a particular job requires specialized resources that can be accommodated while the other jobs may run on more standard and inexpensive resources The ability for the jobs to run on any of a number of resources also increases the application s availability and reliability In addition it may make the application inherently scalable by being able to utilize larger and faster resources at any particular point in time Nevertheless when encountering such a situation it may be worthwhile to check whether the single jobs are really dependent of each other or whether due to its nature they can be split into parallel executable units for submission on a gri
330. ponents can represent the LAN or campus connectivity or even WAN communication between the grid networks The network s responsibility is to provide adequate bandwidth for any of the grid systems Like many other components within the infrastructure the networking can be customized to provide higher levels of availability performance or security Grid systems are for the most part network intensive due to security and other architectural limitations For data grids in particular which may have storage resources spread across the enterprise network an infrastructure that is designed to handle a significant network load is critical to ensuring adequate performance The application enablement considerations should include strategies to minimize network communication and to minimize the network latency Assuming the application has been designed with minimal network communication there are a number of ways to minimize the network latency For example a gigabit Ethernet Chapter 2 Grid infrastructure considerations 39 LAN could be used to support high speed clustering or utilize high speed Internet backbone between remote networks Data topology It would be desirable to assign executing jobs to machines nearest to the data that these jobs require This would reduce network traffic and possibly reduce scalability limits Data requires storage space The storage possibilities are endless within a grid design The storage needs to be secur
331. pplication architecture and have to be addressed up front Chapter 3 Application architecture considerations 61 An important topic is licensing in a grid environment Licensing covers software licenses that are required for running the whole or parts of the grid application From the user perspective performance plays a role This is especially important when opening the grid for broad use This often means unpredictable workload that needs to be taken care of during design of the application Finally grid application development is a topic to be covered before code development and implementation can be started 3 12 1 Software license considerations One question that commonly arises when discussing grid computing is that of software license management There are many products and solution designs that can help with license management Commercial software licenses It is important to discuss how to deal with software licenses that are used inside the grid Insufficient numbers of licenses may seriously hinder the expansion or even exclude certain programs or applications from being used in a grid environment The latter is the case if the grid wants to access personally licensed applications on a personal computer for example in a scavenging mode use of single user licensed software This cannot be done without violation of the license agreement Different models The range of license models for commercial software spans from al
332. pplication development projects and are not elaborated on in depth Others that are new aspects due to the nature of a grid application are provided with greater detail Chapter 3 Application architecture considerations 69 The grid qualification scheme in Appendix A Grid qualification scheme on page 297 represents a summary of most of the essential items to consider It is meant to be a base document to be used during the analysis phase of a grid project In the next chapter we discuss considerations specific to data management 70 Enabling Applications for Grid Computing with Globus Data management considerations No matter what the application it generally requires input data and will produce output data In a grid environment the application may submit many jobs across the grid and each of these jobs in turn will need access to input data and will produce output One of the first things to consider when thinking about data management in a grid environment is management of the input data and gathering of the output data If the input data is large and the nodes that will execute the individual jobs are geographically removed from one another then this may involve splitting the input data into small sets that can be easily moved across the network assuming the individual jobs need access to only a subset of the data The splitting of input data and the joining of output data from the jobs is often handled by a wrapper arou
333. pplications Similar requirements may exist for applications developed in other applications Java Virtual Machine JVM Applications written in the Java programming language require the Java Virtual Machine JVM Java applications may be sensitive to the JVM version To address this sensitivity the application needs to identify the JVM version as a prerequisite The prerequisite may specify the required JVM version or the minimum JVM version 40 Enabling Applications for Grid Computing with Globus Java applications may be sensitive to the Java heap size The Java application needs to specify the minimum heap size as part of its prerequisite Java packages such as J2SE or J2EE may also need to be identified as part of the prerequisites Availability of application across platforms portability The executables of certain applications are platform specific For example an application written in the C or C programming language needs to be recompiled on the target platform before it can be run The application could be pre compiled for each platform and the resulting executables marked for a target platform This will increase the number of qualifying grid host environments where the application can run The limitation of this method will be the cost effectiveness of porting the application to another platform Awareness of OS environment The grid is a collection of heterogeneous computing resources If the application has certain depe
334. programming languages The span of license models covered by each product varies In the following some of the most often used tools are listed FLEXIm In the Linux world there is foremost FLEXIm which offers 11 core models and 11 advanced licensing models The core models include Node locked named user 64 Enabling Applications for Grid Computing with Globus package floating concurrent over network time lined demo enable disable product upgrade versions and a few more The advanced licensing models span from capacity over site license license sharing user groups hosts floating over list of hosts high water mark linger license overdraft and pay per use to network segments and more The complete list of supported licensing can be found at the following Web site http ww globetrotter com flex1m 1mmodels sthm More information about the use and advantages of this de facto standard of electronic license management technology in the Linux world is available at http www globetrotter com flexlm flexlm shtm Tivoli License Manager IBM Tivoli License Manager is a software product that supports management of licenses in a network Due to its nature it is possible to reflect most of the license models being used in the industry IBM Tivoli License Manager can reflect various stages of use during a piece of software s life time The IBM Redbook ntroducing IBM Tivoli License Manager SG24 6888 provides examples of how
335. protected bool onAccept const InetHostAddress amp ia tpport_t port public GridApp InetAddress amp ia h GridApp GridApp InetAddress amp ia TCPSocket ia 4096 boo GridApp onAccept const InetHostAddress amp ia tpport_t port cout lt lt accepting from return true lt lt ia getHostname lt lt lt lt port lt lt endl class GridAppSession public TCPSession private void run void void final void public GridAppSession TCPSocket amp server i GridAppSession GridAppSession TCPSocket amp server TCPSession server h cout lt lt creating session client object lt lt endl void GridAppSession run void string node 342 Enabling Applications for Grid Computing with Globus node t0 node getNode MDS SLA Workload in a real production case For simplicity here we use a fixed address InetAddress addr getPeer tcp lt lt welcome to lt lt addr getHostname lt lt endl tcp lt lt ticket lt lt ticket lt lt endl tcp lt lt hostname lt lt node lt lt endl endSocket void GridAppSession final void delete this f BRRRR RRR RRR RR RR ER ERE RRR EKER KKK RK ERR KEKE KEKE KEKE AA AA ARR AVRA main We start here the GASS server that will be used to transfer the Compile script to the application nodes to perform the library co
336. pt the script takes the tested draw as parameter fexample Submit 3 4 5 32 34 43 n 300000 NodesNumber 8 temporary filename used by by GenerateDrawsGlobus to monitor the job we can also use the process id to increase the granularity TMP HOSTNAME i 0 the loop variable is used is all the for loops the format is 12 34 n oop use here the broker developped for the publication see chapter 8 mds executable for node in mds NodesNumber xargs do Nodes i node loop loop i i i 1 done Chapter 9 Application examples 259 echo The number of draws tested is n a sort the numbers in the specified draw 2 45 23 12 32 43 becomes 2 12 23 32 43 45 so that we could use grep to test this draw and the ouput of the draw programs param echo a tr n sort n xargs Start the gass server on each nodes clean up the Monitoring file when leaving for i in 1oop do rsl amp executable GLOBUS LOCATION bin globus gass server arguments c t r environment LD LIBRARY PATH GLOBUS LOCATION lib file clean up Monitor TMP globusrun o r Nodes i rs1 gt gass server i amp done file should be made executable on all the execution nodes echo Jobs submission to the grid rsl for i in 1oop do echo Nodes i rsl rs1 amp resourceManagerContact V Nodes i V rs1 rs1 executable
337. q Be sure to include the following two lines in the file near the top schemacheck off include usr local globus etc openldap schemas replica schema 2 Start the LDAP daemon export LD LIBRARY PATH GLOBUS LOCATION etc GLOBUS LOCATION libexec slapd f GLOBUS LOCATION etc openldap slapd conf 3 The LDAP daemon sends a message to the syslogd daemon though the local4 facility Add the following line in etc syslogd conf Local4 var log ldap log Issue service syslogd reload to enable LDAP error messages For any issues regarding the LDAP server you can check var log Idap log to determine what the problem might be 4 Initialize the catalog a Open a shell and issue GLOBUS LOCATION etc globus user env sh 212 Enabling Applications for Grid Computing with Globus Note All bold statements are specific to your site and need to be replaced where necessary b Create a file called root Idif with the following contents dn dc itso maya dc com objectclass top objectclass GlobusTop c Create a file called rc Idif with the following contents dn rc test dc itso maya dc com objectclass top objectclass GlobusReplicaCatalog objectclass GlobusTop rc test d Now run the following commands ldapadd x h mO itso maya com D cn Manager dc itso maya dc com w globus f root ldif ldapadd x h m0 itso maya com D cn Manager dc itso maya dc com w globus f rc ldif ldapsearch h ldap server com b dc i
338. r statussum 0 while statussum NodesNumber do echo sleep 5 we poll every 5 seconds statussum 0 for i in 1oop do if s gass server i then contact cat gass server i globus url copy contact Monitor TMP file PWD Monitor i status cat Monitor i statussum status statussum echo Nodes i Monitor cat Monitor i fi done statussum statussum 100 done fStop the gassserver for i in loop do contact cat gass server i globus gass server shutdown contact done C C simple examples Below are more simple examples gassserver C include globus_common h include globus gass server ez h include lt iostream gt include itso_cb h ITSO CB callback invoked when client wants to shutdown the server void callback c function callback setDone main Appendix B C C source code for examples 355 Never forget to activate GLOBUS module globus module activate GLOBUS GASS SERVER EZ MODULE let s define options for our GASS server unsigned long server ez opts 0UL Files openfor writing will be written a line at a time so multiple writers can access them safely server ez opts GLOBUS GASS SERVER EZ LINE BUFFER URLs that have character will be expanded to the home directory of the user who is running the server server ez opts GLOBUS GASS SERVER EZ TILDE EXPAND URLs that have user character will be expande
339. r The code for the ITSO GASS TRANSFER class is provided in ITSO GASS TRANSFER on page 306 and is based on the globus url copy c code of the Globus Toolkit 2 2 This class provides the member 282 Enabling Applications for Grid Computing with Globus transfer between two objects of type GLOBUS_URL GLOBUS_URL is defined in ITSO_GASS_TRANSFER on page 306 and is just a C wrapper to the globus url t C type The member setURL sets up the object by providing a valid URL like gsiftp m0 tmp test The Transfer method is a C wrapper around the Globus asynchronous call to transfer the file from the first URL to the second It is non blocking and the program must call the method Wait to wait for the completion of the transfer GRAM is used to submit the compilation of the GNU CommonC library and the application startup The library is transferred and installed remotely from a remote storage server mO in the source code example to the application node tO in the source code example in the tmp directory created in the home directory of the user under which the Compile script is executed A GASS server is started locally on the front end server and listens on port 20000 It used to copy the script Compile and the executable HelloServer from the front end server to the application server Example 9 15 CommonC library copy and compilation HelloFrontEnd C main We start here the GASS server that will be used to transfe
340. r countries or both AFS IBM Redbooks logo 6 AIXG ibm com amp Sametime CICS Lotus Notes Storage TankTM DB2 Lotus Tivoli DB2 Connect Notes amp WebSphere amp DFS MQSeries xSeries server TM Redbooks The following terms are trademarks of other companies ActionMedia LANDesk MMX Pentium and ProShare are trademarks of Intel Corporation in the United States other countries or both Microsoft Windows Windows NT and the Windows logo are trademarks of Microsoft Corporation in the United States other countries or both Java and all Java based trademarks and logos are trademarks or registered trademarks of Sun Microsystems Inc in the United States other countries or both UNIX is a registered trademark of The Open Group in the United States and other countries Other company product and service names may be trademarks or service marks of others xii Enabling Applications for Grid Computing with Globus Preface This IBM Redbook is the second in a planned series of redbooks addressing grid computing In the first redbook Introduction to Grid Computing with Globus SG24 6895 grid concepts and the Globus Toolkit were introduced In this redbook we build on those concepts to discuss enabling applications to run in grid environments Again we focus on the open source Globus Toolkit In Chapters 1 4 of this publication we look at various factors that should be considered when con
341. r i 8 i i find 8 different number between 1 and 60 do n GetARandomNumberBetween1And60 while find Series begin Series end n Series end Series push front n E let display the result Appendix B C C source code for examples 349 Series sort list lt long int gt iterator j for j Series begin j Series end j cout lt lt j lt lt cout lt lt endl OutputFileMonitor seekp 1 ios beg OutputFileMonitor lt lt 100 InitialDrawNumber DrawNumber InitialDrawNumber while DrawNumber OutputFileMonitor seekp 1 ios beg OutputFileMonitor 100 OutputFileMonitor close Submit script the script takes the tested draw as parameter fexample Submit 3 4 5 32 34 43 n 1000000 NodesNumber 12 temporary working directory on the execution nodes TMP HOSTNAME i20 the loop variable is used is all the for loops the format is 12 3 4 n oop use here the broker developped for the redbook see chapter 8 mds executable for node in mds NodesNumber xargs do Nodes i node loop loop i i i 1 done echo The number of draws tested is n a sort the numbers in the specified draw 2 45 23 12 32 43 becomes 2 12 23 32 43 45 so that we could use grep to test this draw and the ouput of the draw programs param echo a tr n sort n xargs parrarell transfer of the draw executable
342. r more physical instances The catalog may contain one logical entry in the Replica Catalog for each logical file in a collection url gsftp m0 repo rea EA z protocol gsiftp location A list of files file1 file2 file3 location B url ftp ftp lab itso maya com location B protocol ftp list of files file4 file5 logical name gt f size 185802 gt f Size 232802 3 1 9 size 3284802 4 list of files fi n Size 1838602 file 5 size 187812 Figure 4 11 Replica logical view Replica Catalog functions can be used directly by applications by using the C C APIs provided by Globus They provide the following operations Creation and deletion of collection location and logical file entries Insertion and removal of logical file names into collections and locations Listing of the contents of collections and locations A function to return all physical locations of a logical file vvvy 96 Enabling Applications for Grid Computing with Globus Examples are provided in Replication on page 208 by using shells commands provided by the Globus Toolkit 2 2 Replica Location Service RLS The Replica Location Service is a new component that appears in Globus Toolkit 2 4 This component maintains and provides access to information about the physical locations of replicated data This implementation was co develop
343. r the Compile script to the application nodes to perform the library compilation to transfer the HelloServer used on the remote hosts to manage clients requests The GASS server arbitraly listens on port 20000 StartGASSServer 20000 get the hostname using the globus function globus libc gethostname hostname MAXHOSTNAMELEN 1TSO GRAM CLIENT does not start the module lets do it if globus module activate GLOBUS GRAM CLIENT MODULE GLOBUS SUCCESS cerr lt lt Cannot start GRAM module exit 2 h string node we use a fixed address for this simple example but nodes getNodes SLA MDS Workload in a more complex example we should get here the list of nodes where the application is supposed to run node t0 Chapter 9 Application examples 283 variable used in all for loops int i Here we want test the existence of the file as there is no such checking in the ITSO GLOBUS FTP CLIENT class FILE fd fopen commoncpp2 1 0 8 tar gz r if fd NULL printf Error opening commoncpp2 1 0 8 tar gz file exit 2 else that fine lets go for FTP we can close fd descriptor because a new one will be opened for each ITSO GLOBUS FTP CLIENT object fclose fd never forget to activate the Globus module you want to use globus module activate GLOBUS GASS COPY MODULE f EBREA ARA AAA RARA ER RRA KERR KR RR KR ERK RARA KEKE AAA AAA AAA AIAR AAA In
344. rce provider for a limited period of time Use a server that has a better network bandwidth Chapter 9 Application examples 279 front end server P Em y N app resources provider resources provider Figure 9 7 Grid model This extended approach underlines several issues that are managed by the Globus Toolkit 2 2 gt With GSI the Globus Toolkit 2 2 provides the secure infrastructure needed for an application to be spread across different locations gt With GridFTP the Globus Toolkit 2 2 provides a subsystem to easily efficiently and securely move data necessary for the applications gt With GRAM and GASS the Globus Toolkit 2 2 provides mechanisms to easily and securely start remote applications on distributed resources 9 3 1 The Hello World application Let us consider a basic example for such an application A front end server waits for client requests When connected the client is given back a ticket and an application server IP address of where to connect The application answers hello world when the client connects to it The application is started on the application servers by the front end server 280 Enabling Applications for Grid Computing with Globus The executable for the client is HelloClient and takes the front end server host name as a parameter The source code is provided in HelloWorld example on page 341 The executable for the server itself
345. rder to calculate and handle the large number of variables and their effects For each set of parameters a complex calculation can be executed The simulation of a large scale scenario then consists of a larger number of such steps In other words a grid application may consist of a number of jobs that together fulfill the whole task Job Considered as a single unit of work within a grid application It is typically submitted for execution on the grid has defined input and output data and execution requirements in order to complete its task A single job can launch one or many processes on a specified node It can perform complex calculations on large amounts of data or might be relatively simple in nature 3 2 Application flow in a grid In this section we look at the overall flow of a grid enabled application which may consist of multiple jobs Traditional applications execute in a well known and somewhat static environment with fixed assets We need to look at the considerations and value for having an application run in a grid environment where resources are dynamically allocated based on actual needs If taking advantage of multiple resources concurrently in a grid you must consider whether the processing of the data can happen in parallel tasks or whether it must be serialized and the consequences of one job waiting for input data from another job What may result is a network of processes that comprise the application Applicat
346. re and facilities to provide a single sign on environment Through the grid proxy init command or its related APIs a temporary proxy is created based on the user s private key This proxy provides authentication and can be used to generate trusted sessions and allow a server to decide on the user s authorization A proxy must be created before a user can submit a job to be run or transfer data through the Globus Toolkit facilities Depending on the configuration of the environment a proxy may or may not be required to query the information services database Other facilities are available outside of the Globus Toolkit such as GSI Enabled OpenSSH that utilize the same authentication mechanism to create secure communications channels For more information on the GSI Enabled OpenSSH visit http grid ncsa uiuc edu ssh Authorization Authentication is just one piece of the security puzzle The next step is authorization That is once a user has been authenticated to the grid what they are authorized to do In GSI this is handled by mapping the authenticated user to a local user on the system where a request has been received The proxy passed by the operation request such as a request to run a job contains a distinguished name of the authenticated user A file on the receiving system is used to map that distinguished name to a local user Through this mechanism either every user of the grid could have a user ID on each system wit
347. re gkrellm on t1 but will display the graphical interface on mO Example 5 10 Running a graphical application through gsissh globus m0 globus gsissh t1 gkrellm gsissh also supports proxy delegation That means that once the GSI credentials are created on one node a user can log onto other nodes and from there submit jobs that will use the same GSI credentials In Example 5 11 a user connects to t1 and from there can submit a job without the need to regenerate a new Globus proxy Example 5 11 Proxy delegation support on m0 globus m0 globus grid proxy init Your identity 0 Grid 0 Globus O0U itso maya com CN m0user Enter GRID pass phrase for this identity Creating prOXy scudo scena ctm emet mm eem e ie cepa i qm t Rn rr ace laa aes Done Your proxy is valid until Tue Mar 18 04 33 21 2003 globus m0 globus gsissh tl itso tupi com Last login Fri Mar 14 15 16 59 2003 from m0 itso maya com on tl globus t1 globus globus job run al s bin hostname al itso apache com globus t1 globus grid proxy info subject 0 Grid 0 Globus 0U itso maya com CN m0user CN proxy CN proxy Chapter 5 Getting started with development in C C 115 issuer 0 Grid 0 Globus 0U itso maya com CN m0user CN proxy type full strength 512 bits timeleft 11 19 34 For more information see the followings links http www OpenSSH http www openssh org http www GSIopenssh http www nsf middleware org NMIR2 GSIssh instal
348. requires open source software like the Globus Toolkit or Apache WebServer The open source model is based on the principle that anybody an ISV or private person provides software to any interested parties that can be modified customized or improved by the recipient The modifying recipient in turn can offer this changed code to anybody who again can change it when needed So there can be many developers in a loose community participating in development and improvement of a given set of code In this case licenses are not bound to binary executables but cover source code as well The following three licensing models for open source software are the most common though there are several more which may need to be investigated in any specific case BSD MIT Apache all permissive licenses The license models for BSD MIT and Apache are all permissive which means that they allow for free distribution modification and license changes Software without copyright public domain software falls under this category as well For details on BSD licensing see http www opensource org licenses bsd license php For MIT licenses see http www opensource org licenses mit license php For the Apache Software License see http www opensource org licenses apachepl php Chapter 3 Application architecture considerations 63 LGPL persistent license The Lesser General Public License LGPL allows free distribution of the software
349. resulting data of the job may be passed to a data store or message queue for further processing or presentation Chapter 3 Application architecture considerations 57 gt Other APIs when communicating with Web services Web servers application servers news tickers measurement devices or any other external systems the appropriate conditions for data passing in and out have to be taken into consideration In these cases you may use HTTP HTML XML SOAP or other high level protocols or APIs As indicated for a grid application there may not be only one way to pass data for a job but you may use any combinations of the described mechanisms It is advised to program grid jobs in such a way that the data sources and sinks are generically handled for more flexible grid topologies The optimal solution depends on the environment and the requirements to be considered at the architecture and design phase of the grid application 3 9 Transactions Handling of transactions in their strict definition of commit and roll back is not yet well suited for a common grid application The OGSI does not cover these services However a grid application may include subsystems or launch transaction aware operations to subsystems such as CICS The handling of transactions within a grid application easily becomes quite complex with the given definitions and it needs to be carefully applied The added benefits of a grid application may be outweighed by the
350. results next attrs si getAttributes if si getName trim length 0 dn baseDN else dn si getName baseDN System out print n dn dn for NamingEnumeration ae attrs getA11 ae hasMoreElements at Attribute ae next attribute at getID Enumeration vals at getA11 while vals hasMoreElements System out println attribute vals nextElement System out print n The displayResults method above takes the information stored in the results variable parses it into separate attributes and converts it to an enumeration type so it can be printed Example 6 11 GridinfoSearch example 4 of 4 Create new instance of MyGridInfoSearch and use specified filter string public static void main String args MyGridInfoSearch gridInfoSearch new MyGridInfoSearch String filter amp objectclass Mds0s Mds 0s name Linux System out println Your search string is filter gridInfoSearch search filter The above code creates a new instance of MyGridInfoSearch and passes the filter to the search method 144 Enabling Applications for Grid Computing with Globus 6 5 RSL We introduced RSL in 2 1 2 Resource management on page 17 Now we show some programming examples that utilize RSL 6 5 1 Example using RSL Example 6 12 utilizes the org globus rsl package provided by the JavaCoG Kit to parse and display the RSL strin
351. rg NMIR2 Grid Portal Development Kit http doesciencegrid org projects GPDK CommonC http www gnu org software commonc gSOAP Plugin http gsoap2 sourceforge net Related publications 371 Platform Computing http ww platform com DataSynapse http www datasynapse com United Devices http www ud com How to get IBM Redbooks You can search for view or download Redbooks Redpapers Hints and Tips draft publications and Additional materials as well as order hardcopy Redbooks or CD ROMs at this Web site ibm com redbooks 372 Enabling Applications for Grid Computing with Globus Index A Access Control System 88 accounting 5 11 all permissive license 63 Apache 63 application architecture considerations 43 application development 66 Application Development Environments 66 application flow 45 52 Application Programming Interfaces 5 application server 55 application status 234 asynchronous calls 117 authentication 14 15 authorization 14 15 Avaki 92 B bandwidth 77 blocking calls 117 broker 8 23 33 123 124 considerations 33 broker example 127 327 browing MDS with a GUI 127 BSD 63 C C bindings 5 C considerations 53 C 105 C examples 305 C C 66 caching 87 callback 109 250 315 cancel job 235 CAS 88 CCA 67 Certificate Authority 84 CertUtils 136 chargeback 5 11 checkpoint restart 38 56 Chimera 103 Copyright IBM Corp 2003 All rights reserved
352. rid application have to reflect this in order to operate with valid data when executing Especially when using data caching or other replication techniques the currency of the data used by the jobs needs to be assured at any given point in time As discussed in 3 2 2 Serial flow on page 47 the order of data processing by the individual jobs especially the production of input data for subsequent jobs has to be observed 4 1 8 Data topology The issues discussed above about the size of the data network bandwidth and time sensitivity of data determine the location of data or the topology of the data Depending on the job the following data related questions need to be considered gt Is it reasonable that each job or set of jobs accesses the data via a network gt Does it make sense to transport a job or set of jobs to the data location gt ls there any data access server for example implemented as a federated database that allows access by a job locally or remotely via the network gt Are there time constraints for data transport over the network for example to avoid busy hours and transport the data to the jobs in a batch job during off peak hours Chapter 4 Data management considerations 77 gt Is there a caching system available on the network to be exploited for serving the same data to several consuming jobs gt Is the data only available in a unique location for access or are there replicas that are clos
353. ring and joining of results can be handled multiple ways depending in the requirements In the first case the Globus Toolkit does not provide tools to perform the pre and post processing tasks Therefore software will need to be developed to perform the two tasks Shell script and scripting languages like Perl or Python may be appropriate to perform these tasks depending on the type of data store and the size of the data It may be mandatory to use languages like C C which produce compiled executables to achieve acceptable performance In the second case the data will remain distributed on different locations for all jobs that will process this data Therefore users need to have a logical view of this file distributed across a set of nodes This logical view will be provided by a catalog whereas each storage node will store the different parts of the file The Globus Toolkit provides a framework to manage this case It provides an LDAP schema to implement the replica catalog as well as a C C API to access and manage this information The user of a grid environment needs transparent access to its input and output data This data will most of the time be permanently located on remote locations and the job will process local copies only The transparent access to the data has a network cost and it must be carefully qualified Data access transparency also requires that the storage resources be sufficient and this also needs to be qualifie
354. ript For a a short computation on three nodes the result is globus m0 other SubmitGlobus 2 3 45 6 7 8 20 The number of draws tested is 100000 Jobs submission to the grid d2 itso dakota com c2 itso cherokee com cl itso cherokee com amp resourceManagerContact d2 itso dakota com executable GLOBUSRUN_GASS_UR L home globus JYCode other GenerateDrawsGlobus sh arguments m0 itso maya com 100000 2 3 6 7 8 20 45 subjobStartType 1oose barrier file stage in GLOBUSRUN GASS URL home globus JYCode other GenerateDrawsGlo bus GenerateDrawsGlobus m0 itso maya com file clean up GenerateDrawsGlobus m0 itso maya com environment LD LIBRARY PATH GLOBUS LOCATION lib amp resourceManagerContact c2 itso cherokee com executable GLOBUSRUN GASS URL home globus JYCode other GenerateDrawsGlobus sh arguments m0 itso maya com 100000 2 3 6 7 8 20 45 subjobStartType loose barrier file stage in GLOBUSRUN GASS URL home globus JYCode other GenerateDrawsGlo bus GenerateDrawsGlobus m0 itso maya com file_clean_up GenerateDrawsG obus m0 itso maya com environment LD_LIBRARY_PATH GLOBUS LOCATION 1ib Chapter 9 Application examples 261 amp resourceManagerContact cl itso cherokee com executable GLOBUSRUN_GASS_URL home globus JYCode other GenerateDrawsGlobus sh arguments m0 itso maya com 100000 2 3 6 7 8 20 45 subjobStartType loose barrier file stage in GLOBUSRUN GASS UR
355. rnate process can help to determine the status of the first process and even restart it However if the alternate process also fails to respond then we assume that either the host machine has crashed or the network has failed In this case the client must wait until the communication can be reestablished System management Any design will require a basic set of systems management tools to help determine availability and performance within the grid A design without these tools is limited in how much support and information can be given about the health of the grid infrastructure Alternate networks within a grid architecture can be dedicated to perform these functions so as to not hamper the performance of the grid 2 2 3 Topology considerations The distributed nature of grid computing makes spanning across geographies and organizations inevitable As an intra grid topology is extended to an inter grid topology the complexity increases For example the non functional and operational requirements such as security directory services reliability and performance become more complex These considerations are discussed briefly in the following sections 38 Enabling Applications for Grid Computing with Globus Intragrid d Intergrid Figure 2 6 Grid topologies Network topology The network topology within the grid architecture can take on many different shapes The networking com
356. rovide Globus Toolkit functionality within their code without calling scripts or in some cases without having Globus installed There are several COGs available for GT2 development CoGs are currently available for Java Python CORBA Perl and Matlab The Java CoG Kit is the most complete of all the current CoG Kits It is an extension of the Java libraries and classes that provides Globus Toolkit functionality The most current version is 1 1 alpha and is compatible with GT2 and GT3 The examples in this chapter use JavaCoG Version 1 1a JavaCoG provides a pure Java implementation of the Globus features This chapter provides examples in Java for interfacing with the following Globus components functions Proxy Credential creation and destruction GRAM Job submission and job monitoring MDS Resource searching RSL Resource specification and job execution GridFTP Data management GASS Data management vvvvvy 6 2 GSI Proxy The JavaCoG 1 1a Toolkit provides a sample application written in Java to create a proxy It has the same name as the standard Globus command line function grid proxy init This tool by default creates a proxy in a format that will be used in Globus Toolkit V3 which is not compatible with Globus Toolkit V2 To create a proxy valid for Globus Toolkit V2 2 the old option must be set This can be done by simply passing old as a parameter when executing the Java version of grid proxy init In order to creat
357. rs and has been involved with Grid Computing since December 2002 Roman was working for two years in IBM ICAM as a system administrator After that he went to the Swiss Lotus Notes development team and 1 year xiv Enabling Applications for Grid Computing with Globus ago joined the Sales Operations team as a developer He holds a degree of Informatiker from GIBZ in Switzerland His areas of expertise include Java Development Lotus Notes Development amp Administration Lotus Sametime Development Intelligent Agent Development Linux operating system Grid technologies and Web Services Seong Steve Yu is an Advisory Software Engineer on the WebSphere Beta team IBM Software Group in Austin Texas He has been with IBM for 20 years the last three years with the WebSphere product Steve led the development of a WebSphere V5 migration guide redbook He developed the original design and the prototype migration tool for JSP and Servlet migration Steve has a BS degree in Mathematics Computer Science from UCLA and an MS degree in Computer Science from CSU and he is currently pursuing a PhD in Computer Science at NSU Ft Lauderdale His current research interests include autonomic computing machine learning and multi agent systems Thanks to the following people for their contributions to this project Paul Bate IBM Global Services Architecture and Technology Center of Excellence Andreas Hermelink Grid Computing WW Technical S
358. rticular operating system and hardware configuration This poses possible issues if an application is simply loaded on a new grid host and run This issue may be resolved if the service provider makes an arrangement with the resource provider so that the applications optimum configuration and resource requirements are identified ahead of time and applied when the application is run Contention for resource Resource contention is always a problem when resources are shared If resource contention impacts performance significantly alternate resources may need to be introduced For example if a database is the source of contention then introducing a replica may be an answer In addition the network may need to be divided to separate the traffic to the databases Optimum sharing of the grid hosts may be achieved by a proper scheduling algorithm and workload balancing For example the shortest job first SJF batch job scheduling algorithm may provide the best turnaround time Reliability Failures in the grid resource and network can cause unforeseen delays To provide reliable job execution the grid resource may apply various recovery methods for different failures For example in the checkpoint restart environment some amount of delay will be incurred each time a checkpoint is taken A much longer delay may be experienced if the server crashed and the application was migrated to a new server to complete the run In other instances the delay m
359. rver 0 cece eee ees 151 6 6 3 WRECOPYi rhe bekkelsR A eed nee et Rede ead Pe ees 154 6 0 GASS ia oe FY Ek eet RS ES ee SOM De od ee el Haat RE 155 6 7 1 Batch GASS example 156 6 7 2 Interactive GASS example 0 00 eee 158 06 8 Summary c cssixiefanur ic Rex enhadiYiesbbe5iB igd bbs EN 161 Chapter 7 Using Globus Toolkit for data management 163 7 1 Using a Globus Toolkit data grid with RSL auaa aaua 165 7 2 Globus Toolkit data grid low level API globus_io 169 7 2 1 globus io example ee 172 7 2 2 Skeleton source code for creating a simple GSI socket 173 7 3 Global access to secondary storage 178 7 3 1 Easy file transfer by using globus gass copy API 178 7 3 2 globus gass transfer API 187 7 3 3 Using the globus gass server ez API 188 7 3 4 Using the globus gass server command 192 7 3 5 Globus cache management cee eee eee 192 4 4 GridE TP iilam ELLE eee 194 7 4 4 GridFTP examples eee 195 7 4 2 Globus GridFTP APIS llle eren 195 TS RepliCationzz e teret Les re e repe bed ek e ist Re Rea 208 7 5 1 Shell commands 209 7 5 2 Replica example 209 7 5 3 Installatiori oem nex RR nS 211 7 60 Summary oslsie eae a Pe ae m db ye ew imd we de ded 213 Chapter 8 Developing a portal e eee 215 8 1 Building a simple portal 216 8 2 Integrating portal function with
360. rver C GLOBUS PKG LIBS 3 Start the monitoring program on mO itso maya com by issuing gsisocketserver 4 Submit the job on t2 itso tupi com globus m0 globus grid proxy init Your identity 0 Grid 0 Globus OU itso maya com CN globus Enter GRID pass phrase for this identity Creating Proxy airone aa Nx ba RU Pa eR NUR TR Done Your proxy is valid until Mon Mar 3 23 37 23 2003 globus m0 globus gsiscp gsiclient2 t2 itso tupi com gsiclient2 100 RRA rR a AE e e ESE RIO O OOO 126 KB 00 00 globus m0 globus globusrun o r t2 amp executable home globus gsisocketclient arguments http m0 itso maya com 10000 m0 itso maya com 10000 23 On the monitoring side you should see globus m0 globus gsisocketserver Hello world secured 23 7 2 2 Skeleton source code for creating a simple GSI socket Below we review the skeleton source code for creating a simple GSI socket Example 7 12 globus io client gsisocketclient C include include include include macro lt iostream gt lt globus_io h gt globus_gss_assist h lt string gt to use a C string class as a char parmeter in a C function Chapter 7 Using Globus Toolkit for data management 173 define STR a const_cast lt char gt a c_str f E EFAAAARARAAAARAA RARA AAA AA RAA ARA ARR ARR AAA RARA ARA KARA KARA EKER KR ER RK KER ER ERE KEK This macro is defined for debugging reasons It checks the sta
361. s globus job run args You al s MyProg bl s MyProg cl s MyProg Chapter 5 Getting started with development in C C 111 Hello You from al itso apache com Hello You from bl itso bororos com Hello You from cl itso cherokee com globus job submit This shell command submits a job in the background so that you can submit a job log out of the system and collect the results later The job is managed via a URL also known as a job contact created at job submission The syntax is the same as for globus job run except that the program must refer to an absolute path and the s option cannot be used Example 5 5 globus job submit example globus m0 globus globus job submit al myjobs LongRunningJob https al itso apache com 47573 22041 1047929562 The job contact returned the https string in the example can then be used with the following commands gt globus job status job contact to get the status of the job pending active done failed others gt globus job get ouput job contact to retrieve the output of the job gt globus job cancel job contact to cancel the job gt globus job clear job contact to clear the files produced by a job Example 5 6 Retrieving information about a job globus m0 globus globus job status https al itso apache com 47573 22041 1047929562 ACTIVE globus m0 globus globus job cancel https al itso apache com 47573 22041 1047929562 Are you sure you want to
362. s Application and Standards Stallings W 2000 Prentice Hall Inc A standard for architecture description by R Youngs D Redmond Pyle P Spaas and E Kahan IBM Systems Journal Volume 38 Number 1 1999 Enterprise Solutions Structure available at http ww research ibm com journal sj 381 youngs htm On Death Taxes and the Convergence of Peer toPeer and Grid Computing by lan Foster Adriana lamnitchi http people cs uchicago edu anda papers foster grid vs p2p pdf Foster et al The Grid Blueprint for a New Computing Infrastructure Morgan Kaufmann 1999 ISBN 1558604758 The Anatomy of the Grid Enabling Scalable Virtual Organizations found at http www globus org research papers anatomy pdf Copyright IBM Corp 2003 All rights reserved 367 A Brief Introduction to Grid Technology found at http www bo infn it alice introgrd introgrd Computational Grids found at http www globus org research papers chapter2 pdf The Globus Project A Status Report found at ftp ftp globus org pub globus papers globus hcw98 pdf gt GridFTP Update January 2002 found at http www globus org datagrid deliverables GridFTP Overview 200201 pdf gt Grid Service Specification found at http www gridforum org ogsi wg drafts GS_Spec_draft03_2002 07 17 pdf Internet Draft GridFTP Protocol Extensions to FTP for the Grid found at http www fp mcs anl gov ds1 GridFTP Protocol RFC Draft pdf gt Internet
363. s The Storage Tank implementation is currently built on a Fibre Channel network However it could also be built on any other high speed network such as Gigabit Ethernet iSCSI for which network attached storage devices have become available Storage Tank clients can access data directly from storage devices using the high bandwidth provided by a Fibre Channel or other high speed network Direct data access eliminates server bottlenecks and provides the performance necessary for data intensive applications An installable file system IFS is installed on each IBM Storage Tank client An IFS directs requests for metadata and locks to an IBM Storage Tank server and sends requests for data to storage devices on the SAN Storage Tank clients can access data directly from any storage device attached to the SAN Enabling Applications for Grid Computing with Globus Existing IP Network for Client Server Communications Storage Tank Protocol Linux client AIX client Storage Tank Fiber Channel Network Storage Area Network Sever Storage fia dd S m ta data ever Storage Tank Sever si Server Cluster for Load Shared Storage Data Balancing Fail Over Processing Scalability Figure 4 10 Storage Tank architecture The Global File System GFS GFS allows multiple servers on a Storage Area Network to have read and write access to a
364. s as well as a GUI application and a Web application SRB supports the GSI security infrastructure that permits the integration of the SRB into the Globus Toolkit environment See http www npaci edu DICE security index html The Authentication and Chapter 4 Data management considerations 101 Integrity of Data library libAID needs to be installed to permit SRB to use GSI authentication LibAID provides an API to GSI For more information see the following Web site http ww npaci edu DICE SRB 4 3 Some data grid projects in the Globus community Many data centric grid projects in the research community are based on the Globus Toolkit 2 They have developed various middleware to help handle the data management considerations Here is a short list of large data grid projects whose middleware source codes are available 4 3 1 EU DataGrid The DataGrid project is a project funded by the European Union that aims to enable access to geographically distributed data servers It is based on the Globus Toolkit 2 2 and therefore uses the Globus Data Grid framework GridFTP protocol and replica management This project implements a middleware layer between applications and the Globus Toolkit 2 The Grid Data Mirroring Package GDMP is a file replication tool that replicates files from one site to another site It can manage replica catalog entries for file replicas Note that all files are assumed to be read only GDMP is a collaboratio
365. s ftp client restart marker init For a complete description of the globus ftp client API see http www unix globus org api c globus ftp client html index html Chapter 7 Using Globus Toolkit for data management 201 Parallelism GridFTP supports two kind of transfers gt Stream mode is a file transfer mode where all data is sent over a single TCP Socket without any data framing In stream mode data will arrive in sequential order This mode is supported by nearly all FTP servers Extended block mode is a file transfer mode where data can be sent over multiple parallel connections and to multiple data storage nodes to provide a high performance data transfer In extended block mode data may arrive out of order ASCII type files are not supported in extended block mode Use globus ftp client operationattr set mode to select the mode Note that you will need a control handler of type globus ftp client operationattr tto define this transfer mode and it needs to be initialized before being used by the function globus ftp client operationattr init Currently only a fixed parallelism level is supported This is interpreted by the FTP server as the number of parallel data connections to be allowed for each stripe of data Use the globus ftp client operationattr set parallelism to set up the parallelism You also need to define a layout that defines what regions of a file will be stored on each stripe of a multiple str
366. s is achieved when you submit a job via the gatekeeper that supports proxy delegation or using gsissh 7 3 4 Using the globus gass server command globus gass server is a simple file server that can be used by any user when necessary from a Unix shell It uses the secure https protocol and GSI security infrastructure The GASS server can be started with or without GSI security The security mode is controlled by the i option that deactivates the GSSAPI security This way the server will use http protocol instead of https protocol The c option allows a client to shut down the server by writing to dev globus gass client shutdown See the previous example The o and e options allow a client to write to standard output and standard error The r and w options authorize a client to respectively read and write on the local file system where the GASS server is running The t option expands the tilde sign in a URL expression to value of the user s home directory globus gass server example On mO itso maya com globus mO globus globus gass server o e r w p 10001 On t2 itso tupi com globus m0 globus globus url copy file home globus FileToBeCopied https m0 itso maya com 10001 dev stdout You can see the contents of the FileToBeCopied file on mO 7 3 5 Globus cache management The globus gass cache API provides an interface for management of the GASS cache 192 Enabling Applications for Grid Computing with Globus
367. s of the machines computers and networks such as the number of processors available at this moment what bandwidth is provided and the type of storage available Application enablement considerations Broker When designing an application for execution in a grid environment it is important to understand how resources will be discovered and allocated It may be up to the application to identify its resource requirements to the broker so that the broker can ensure that the proper and appropriate resources are allocated to the application 2 1 8 Inter process communications IPC A grid system may include software to help jobs communicate with each other For example an application may split itself into a large number of sub jobs Each of these sub jobs is a separate job in the grid However the application may implement an algorithm that requires that the sub jobs communicate some information among them The sub jobs need to be able to locate other specific Chapter 2 Grid infrastructure considerations 33 2 1 9 Portal 34 sub jobs establish a communications connection with them and send the appropriate data The open standard Message Passing Interface MPI and any of several variations are often included as part of the grid system for just this kind of communication MPICH G2 MPICH G2 is an implementation of MPI optimized for running on grids It combines easy secure job startup excellent performance data conversion and mu
368. s server url lt lt end wait until it is finished that means that the put requests to the URL https host dev globus gass client shutdown 1TS0 CB implements the symchronization mechanism by using a mutex and a condition variable callback Wait shutdown callback stop everything globus gass server ez shutdown listener globus module deactivate GLOBUS GASS SERVER EZ MODULE To compile this program issue use the following Makefile globus makefile header flavor gcc32 globus gass server ez globus common globus gass transfer globus io globus gass copy globus header include globus header all gassserver 55 0 C g g c GLOBUS CPPFLAGS lt o e gassserver gassserver o itso cb o g g o 0 GLOBUS CPPFLAGS GLOBUS LDFLAGS GLOBUS PKG LIBS This program can be launched on one node for example mO itso maya com and by using gasscopy from another node for example t2 itso tupi com we will be able to copy files display files on mO and even shut down the GASS server On mO itso maya com gassserver On t2 itso tupi com gasscopy FileToBeCopied https m0 itso maya com 10000 FileCopied gasscopy FileToBeDisplayed https m0 itso maya com 10000 dev stdout gasscopy None https m0 itso maya com 10000 dev globus_gass_client_shutdown Chapter 7 Using Globus Toolkit for data management 191 Note On both server and client side you need to have the same credentials Thi
369. s should be addressed to the suppliers of those products This information contains examples of data and reports used in daily business operations To illustrate them as completely as possible the examples include the names of individuals companies brands and products All of these names are fictitious and any similarity to the names and addresses used by an actual business enterprise is entirely coincidental COPYRIGHT LICENSE This information contains sample application programs in source language which illustrates programming techniques on various operating platforms You may copy modify and distribute these sample programs in any form without payment to IBM for the purposes of developing using marketing or distributing application programs conforming to the application programming interface for the operating platform for which the sample programs are written These examples have not been thoroughly tested under all conditions IBM therefore cannot guarantee or imply reliability serviceability or function of these programs You may copy modify and distribute these sample programs in any form without payment to IBM for the purposes of developing using marketing or distributing application programs conforming to IBM s application programming interfaces Copyright IBM Corp 2003 All rights reserved xi Trademarks The following terms are trademarks of the International Business Machines Corporation in the United States othe
370. se of resource information I Local resource information Information Provider Local resource information Resources Eu Set lia ee aS SS ee Sree ee re Idapadd delete modify slapd LDAP base Figure 2 1 MDS overview Grid Resource Information Service GRIS GRIS is the repository of local resource information derived from information providers GRIS is able to register its information with a GIIS but GRIS itself does not receive registration requests The local information maintained by GRIS is updated when requested and cached for a period of time known as the time to live TTL If no request for the information is received by GRIS the information will time out and be deleted If a later request for the information is received GRIS will call the relevant information provider s to retrieve the latest information 24 Enabling Applications for Grid Computing with Globus Grid Index Information Service GIIS GIIS is the repository that contains indexes of resource information registered by the GRIS and other GIISs It can be seen as a grid wide information server GIIS has a hierarchical mechanism like DNS and each GIIS has its own name This means client users can specify the name of a GIIS node to search for information Information providers The information providers translate the properties and status of local resources to the format defined in the schema and configurati
371. sed as one command With the string array Ibin su c and subCmd are treated separately and execute correctly String cmd bin su c subCmd mOuser cmdResult doRun cmd Example 8 5 Sample code to run non Java commands from Web portal public String doRun String cmd throws IOException ArrayList cmdOutput Process p InputStream cmdOut BufferedReader brOut InputStream cmdErr BufferedReader brErr String line 232 Enabling Applications for Grid Computing with Globus cmdOutput new ArrayList p Runtime getRuntime exec cmd cmdOut p getInputStream brOut new BufferedReader new InputStreamReader cmdOut get the command output cmdOutput clear while line brOut readLine null cmdOutput add line cmdErr p getErrorStream brErr new BufferedReader new InputStreamReader cmdErr get error message while line brErr readLine null cmdOutput add line try p waitFor catch InterruptedException e System out println Command cmd interrupted e return String cmdOutput toArray new String 0 Security In the sample code in Example 8 6 the grid proxy init command is executed to get a valid proxy The su c command userid is used to switch to the correct user to run the command Example 8 6 Sample code to run grid proxy init from Web portal public String doProxy String cmdResult null
372. setDataChannelProtection GridFTPSession PROTECTION SAFE To send a file to a server we have to provide an interface to our local file This can be done using the DataSource interface as shown in Example 6 25 or using the DataSourceStream Note however that DataSourceStream does not work with extended block mode As we are using the extended block mode we have to use the DataSource interface Example 6 25 GridFTP client server example 4 of 6 public void ClientToServer String localFileName String remoteFileName throws Exception DataSource datasource null datasource new FileRandomIO new java io RandomAccessFile localFileName rw client extendedPut remoteFileName datasource null When receiving a file from a server we have to provide a local file interface to write the data to In this case it is the DataSink interface Again if extended block mode is not used the DataSinkStream can be used instead 152 Enabling Applications for Grid Computing with Globus Attention By default the GridFTPClient is passive so it can receive files As we are going to use the same GridFTPClient to send data we have to set it to active and our local to passive This can be done using client setLocalPassive client setActive Note that the passive side must always be set first Example 6 26 GridFTP client server example 5 of 6 public void ServerToClient String localFileName String remoteFileName throws Exception l
373. sist globus ftp client globus ftp control globus gram job globus common globus gram client globus gass server ez globus header 2 Use the Makefile shown in Example 9 17 to compile the program Example 9 17 Second example Makefile include globus header all HelloServer HelloClient HelloFrontEnd o o 0 C g c GLOBUS CPPFLAGS lt o e 286 Enabling Applications for Grid Computing with Globus HelloServer HelloServer C g g I usr local include cc 2 L usr local lib o 0 1ccgnu2 lpthread 1d1 HelloClient HelloClient C g g I usr local include cc 2 L usr local lib o 0 1ccgnu2 lpthread 1d1 HelloFrontEnd HelloFrontEnd o itso gram job o itso cb o itso gass copy o itso gass server o g o I usr local include cc 2 L usr local lib GLOBUS CPPFLAGS GLOBUS LDFLAGS GLOBUS PKG LIBS lccgnu2 lpthread 1d1 Then use make all to obtain the three executables 9 3 5 Execution In this publication example the storage server is mO which also acts as the front end server The source file for GNU Common C classes is stored in Amp commoncpp2 1 0 8 tar gz on mO tO is the application server You must generate a valid proxy with grid proxy init before running the test On mO start the Hello front end server globus m0 globus HelloFrontEnd we are listening on https m0 itso maya com 20000 library compilation on t0 amp executable https m0 itso maya com 20000 home globus JYCode
374. ssion The script GenerateDrawsGlobus sh is used to invoke GenerateDrawsGlobus and to perform the simulation on each execution node Example 9 4 GenerateDrawsGlobus sh First argument is the hostname Second arguement is the number of draws to simulate third argument is the draw to test 1 21 32 12 24 43 45 chmod x GenerateDrawsGlobus 1 GenerateDrawsGlobus 1 1 2 grep 3 amp amp echo GOT IT on HOSTNAME GenerateDrawsGlobus sh is used as an intermediary to start the computation instead of directly invoking GenerateDrawsGlobus It is needed because it performs three actions that cannot be described in one RSL string gt It make GenerateDrawsGlobus executable gt It invokes GenerateDrawsGlobus gt It pipes the GenerateDrawsGlobus output through grep We use the local GASS server that is started with globusrun and the s option to perform the movement of the executables GenerateDrawsGlobus sh and GenerateDrawsGlobus Both files are staged in the execution nodes see the SubmitGlobus script executable GLOBUSRUN_GASS_URL PWD GenerateDrawsGlobus sh file stage in A GLOBUSRUN GASS URL PWD GenerateDrawsGlobus GenerateDrawsGlobus TMP Enabling Applications for Grid Computing with Globus TMP is used for the same reason as in the previous example to avoid conflicts between jobs submitted from different nodes so that they do not work on the same files TMP equals HOSTNAME actually the submission no
375. st gass attr 310 Enabling Applications for Grid Computing with Globus h void ITSO GASS TRANSFER Transfer GLOBUS FILE amp globus source file GLOBUS URL amp destURL setDestination destURL globus result t result globus gass copy register handle to url amp gass copy handle globus source file get globus io handle destURL getURL amp dest gass copy attr itso gass copy url copy callback void this h void ITSO GASS TRANSFER Transfer GLOBUS URL amp sourceURL GLOBUS FILE amp globus dest file setSource sourceURL globus result t result globus gass copy register url to handle amp gass copy handle sourceURL getURL amp source gass copy attr globus dest file get globus io handle itso gass copy url copy callback void this E void ITSO GASS TRANSFER Transfer GLOBUS URL amp sourceURL GLOBUS_URL amp destURL setSource destURL setDestination destURL globus result t result globus gass copy register url to url amp gass copy handle sourceURL getURL amp source gass copy attr destURL getURL amp dest gass copy attr itso gass copy url copy callback void this ITSO GLOBUS FTP CLIENT A wrapper for GridFTP capabilities itso globus ftp client h ifndef ITSO ITSO GLOBUS FTP CLIENT H define ITSO ITSO GLOBUS FTP CLIENT H include cstdio Appendix B C C source code for examples 311 include lt iostream gt include globus_ftp_client h incl
376. stURL getURL amp dest_gass_copy_attr globus l1 url copy monitor callback void amp monitor Chapter 7 Using Globus Toolkit for data management 185 h f E FEAR AAA ARA AAA AA AAA AAA AAA AAA AAA AAA AAA RARA AAA AIA AAA RATA f BRRRR RRR RRR AA AAA AAA AAA AA RK KKK RK ERK ERK KR EKER ERE RRR ERE ERE main int argc char argv char localFile strdup argv 1 char destURL strdup argv 2 cout lt lt localFile lt lt endl lt lt destURL lt lt end Globus modules needs always to be activated return code not checked here globus module activate GLOBUS GASS COPY MODULE Callback activation to monitor data transfer MONITOR monitor convert file into a globus io handle GLOBUS FILE globus source file localFile check if this is a valid URL GLOBUS URL dest url if dest url setURL destURL exit 2 we do not manage gsiftp transfer not yet see ITSO0 GASS TRANSFER for that or globus url copy c if dest url getMode GLOBUS GASS COPY URL MODE GASS cerr lt lt You can only use GASS copy lt lt endl exit 1 GASS_TRANSFER transfer transfer setDestination dest url Use Binary mode transfer setBinaryMode transfer startTransfer globus source file dest url monitor Way to wait for a cond signal by using a mutex and a condition variable These three calls are included in the Wait method of the ITSO CB call but they st
377. status cat Monitor i Appendix B C C source code for examples 351 statussum status statussum echo Nodes i Monitor cat Monitor i done statussum statussum 100 done cleanup the tmp directory for i in 1oop do wait ProcessID i gsissh p 24 Nodes i rm fr TMP amp ProcessID i done GenerateDrawsGlobus C To compile this program just issue g o GenerateDrawsGlobus GenerateDrawsGlobus C include lt cstdlib gt include lt unistd h gt include lt list gt include lt algorithm gt include lt string gt include lt fstream gt int GetARandomNumberBetweenlAnd60 returnrandom RAND MAX 60 1 h void initrandom unsigned seed define RANDSIZE 256 static char randstate RANDSIZE initstate seed randstate RANDSIZE the first argument is the hostname provided by SubmitGlobus script the second argument is the number of draws that must be generated main int argc char argv initrandom getpid seeding for a new sequence of pseudo random integers let generate 8 number between 1 and 60 list long int Series long int n long long DrawNumber InitialDrawNumber ofstream OutputFileMonitor string filename filename Monitor filename append argv 1 OutputFileMonitor open filename c_str 352 Enabling Applications for Grid Computing with Globus DrawNumber ato11 argv 2 InitialDrawNumber DrawNumber do
378. stinations location entries to include the new files gt The publishing operation takes a file from a storage system that is not represented in the replica catalog copies the file to a destination storage system that is represented in the replica catalog and updates the corresponding location and logical collection entries 4 2 4 Mirroring For safety and performance reasons data are usually mirrored across a set of nodes This way several access points are provided for jobs that need to process this data and data brokering can be used to determine which access point needs to be used according to various criteria such as the subnet where the job is run or user identification Mirroring consists of being able to synchronize data manipulations that occur at different locations The mirroring can be synchronous or asynchronous mirroring happens at certain time intervals The Globus Toolkit does not provide mirroring capabilities but the European DataGrid project and the Particle Physics Data Grid project developed the Grid Data Mirroring Package on top of the Globus Toolkit 4 2 5 Caching Caching provides temporary storage on the execution nodes and avoids network access during job execution The primary purpose of the cache is efficiency Programs and any prerequisite modules that are required to invoke a job as well as input data are good candidates to be stored locally on each execution node A suitable case is when a job needs
379. such as those with meta schedulers the complexities of coordinating concurrent jobs or ensuring certain jobs execute at a specific time can become complex especially if there are different schedulers for different domains gt Scheduling policy Scheduling can be implemented with different orientations Application oriented Scheduling is optimized for best turn around time System oriented Optimized for maximum throughput A job may not be started immediately It may be interrupted or preempted during execution It may be scheduled to run overnight Grid information service The interaction between the scheduler and the information service can be complex For instance if the resource is found through MDS before the job is actually scheduled then there may be an assumption that the current resource status will not change before execution of the job Or a more proactive mechanism could be used to predict possible changes in the resource status so proactive scheduling decisions may be made Resource broker Typically a resource broker must interface with the scheduler 2 1 6 Load balancing Load balancing is concerned with the distribution of workload among the grid resources in the system Though the Globus Toolkit does not provide a load balancing function under certain environments it is a desired service As the work is submitted to a grid job manager the workload may be distributed in a push model pull model or
380. t cannot be used endl globus module deactivate GLOBUS GRAM CLIENT MODULE To compile the above program 1 Generate the globus variables used in the Makefile globus makefile header flavor gcc32 globus gram job globus header 2 Then use the following Makefile include globus header all CheckNodes o DI 55 0 C g g c I GLOBUS CPPFLAGS lt o e CheckNodes CheckNodes o g g o 0 GLOBUS CPPFLAGS GLOBUS LDFLAGS GLOBUS PKG LIBS 3 Issue make to compile When this program executes you will see results similar to the following globus m0 JYCode CheckNodes al itso tupi com al itso tupi com cannot be used globus m0 JYCode CheckNodes tl itso tupi com tl itso tupi com is okay 122 Enabling Applications for Grid Computing with Globus Job resubmission In this example by using ITSO_GRAM_JOB we submit a job check if it has failed and if so submit it again to another host One simple method is to get three nodes from the broker and submit the job to the next node when it fails on the previous one The job state management is managed in the callback function shown in Example 5 12 on page 119 We declare that we want to monitor all changes in the state of the job GLOBUS_GRAM_PROTOCOL_JOB_STATE_ALL option passed to the globus_gram_client_register_job_request function Then the callback modifies or not the status of the job via the SetFailed method provided by
381. t RW Small gt nearly unlimited check out concurrent jobs on each node Network Small gt high bandwidth speed network LAN gt WAN Time Data always sensitive valid gt time data depending data Data type Commonly Character available sets unicode in SBCS network gt different unicode in DBCS gt inconformity of character codes on network Appendix A Grid qualification scheme 301 Qualification criteria Weight factors H M L Com ment Range Effort Skills show low to high stoppers efforts special care base values Datatype Uniform use of Multi set of multimedia media formats gt mixed formats use of formats Uniform use of encryption techniques available gt varying use of encryption techniques on network Security Commonly policy agreed on among all grid users gt discrepancies between involved parties Time con No time straints restrictions apply Strong need for timely execution and data provisioning Migration Grid in fixed needs environment gt grid application based on common standard gt grid likely to migrate on different platforms 302 Enabling Applications for Grid Computing with Globus Qualific Amountof data Job topology Data topology Network scalability Software licensing Nn Com ment show stoppers special care base values ation criteria Weight factors H M L Range Effort Skills
382. t as a sample on which readers can build a more robust implementation that meet their specific needs 244 Enabling Applications for Grid Computing with Globus Application examples This chapter provides several examples of simple applications that have been enabled to run in a grid environment These samples provide many examples of techniques and help solidify concepts that may be useful to the application developer They are provided as programming examples that may be useful to readers in developing more sophisticated applications for their businesses Copyright IBM Corp 2003 All rights reserved 245 9 1 Lottery simulation program The first application simply utilizes the GSI OpenSSH module Many people will not consider it a true grid application as it does not use most of the facilities provided by the Globus Toolkit and their is little ability to manage the application and control its environment However it is an example of the power of using the GSI and GSI OpenSSH packages to allow multiple systems to work together to provide a solution After presenting the GSI OpenSSH version of the program we then provide a true grid enabled version that does utilize the Globus Toolkit facilities 9 1 1 Simulate a lottery using gsissh in a shell script GSI OpenSSH is a modified version of the OpenSSH client and server that adds support for GSI authentication GSIssh can of course be used to remotely create a shell on a remote system t
383. t for data management 203 if err else fprintf stderr 5s globus object printable to string err if eof FILE fd FILE user arg int rc rc fread buffer 1 MAX BUFFER SIZE fd if ferror fd SUCCESS printf Read error in function data cb errno d n errno return globus ftp client register write handle buffer rC global_offset feof fd SUCCESS data_cb void fd global_offset rc if eof else globus libc free buffer else return data cb EEE K K H k kke ERK RR ke ER ERE ke ke H ke Ke Main Program K KE K e e ke e H ke e H ke e H AE E K K KK ER int main int argc char argv globus_ftp_client_handle_t handle globus ftp client operationattr t attr globus ftp client handleattr t handle attr globus byte t buffer globus result t result char src char dst FILE fd 204 Enabling Applications for Grid Computing with Globus globus ftp control parallelism t parallelism globus ftp control layout t layout int i EEE EK k RRR RRR EKER ERE RK KERR KR ERK KERR ERK Process the command line arguments KKK KR KKK KKK ERK ERK KK EK KK ERE REKKE KEKE if argc 3 printf Usage ext put local_file DST_URL n return ERROR else argv 1 argv 2 src dst BRR RRRRRE RRR ER ERK KERR KEE AAA ARA Open the local source file KAR KR KKK KKK KERR KEKE KEKE REKEKE
384. t td gt lt b gt Job Id lt td gt out printIn lt td gt Job Results lt b gt lt td gt out printIn tr for int i 0 i lt size i String myJobId myJobIds i out printIn tr out print td myJobId lt td gt out printIn td sendResult doGetResult myJobId out printIn td out printIn tr 240 Enabling Applications for Grid Computing with Globus out printIn table out printIn body out printIn htm1 private void doLogout System out print ln doLogout forwarding to login page try RequestDispatcher rd getServletContext getRequestDispatcher login html rd forward req res catch javax servlet ServletException e System out printIn e catch java io IOException e System out print In e private void invalidSelection Something was wrong with the client input System out printIn invalid selection String title Invalid selection out printIn html out printIn head out printIn title title lt title gt out printIn head out println body bgcolor cfd09d text 000099 gt out println hl align center gt title lt h1 gt out print ln lt body gt out print ln lt html gt private void invalidInput Something was wrong with the client input System out print n in
385. t the grid could include several clusters with copies of a parallel application 3 3 4 Interactive jobs Interaction with a grid application is most commonly done via the grid portal or grid server interface This implies that other than launching the job there should not be on going interaction between the user and the job Of course if we go back to our initial view of the gird as a virtual computing resource it is certainly feasible to think of an application requiring user interaction to be launched on any appropriate resource within the grid as long as a secure and reliable communications channel could be created and maintained between the user and the resource Though the GSI Enabled SSH package is available and could be used to create a secure session the Globus Toolkit does not provide any tools or guidance for supporting such an application There would be many considerations and issues involved in the development and deployment of such an application within a grid environment We will not discuss this type of application within the grid context any further in this publication 3 4 Programming language considerations Whenever an application is being developed the question of the programming language to be used arises The grid environment may include additional considerations Jobs that are made for high performance computing are normally written in languages such as C or Fortran Those jobs whose individual execution time does
386. t you must have a valid Globus proxy and your CLASSPATH must contain the location all of the JavaCog jar files along with the current directory Without having a valid Globus proxy you will receive the error Failed to search GSS OWNYQ6NTEOAUVGWG Without having the proper CLASSPATH you will receive the error Failed to search SASL support not available GSS OWNYQ6NTEOAUVGWG Example 6 8 shows the import statements and variable declarations for the MyGridInfoSearch class Example 6 8 GridinfoSearch example 1 of 4 import java util Hashtable import java util Enumeration import java net InetAddress import java net UnknownHostException import javax naming Context import javax naming NamingEnumeration import javax naming NamingException import javax naming directory Attribute import javax naming directory SearchControls import javax naming directory SearchResult import javax naming directory Attributes import javax naming ldap LdapContext import javax naming ldap InitialLdapContext import org globus mds gsi common GSIMechanism we could add aliasing referral support public class MyGridInfoSearch Default values private static final String version org globus common Version getVersion private static final String DEFAULT CTX com sun jndi ldap LdapCtxFactory private String hostname t3 itso tupi com private int port 2135 private String baseDN mds vo name local o grid
387. t you only want to run the executable once Below is a set of examples to illustrate cache management using Globus Toolkit shell commands Example 7 19 shows how to create a copy on t2 itso tupi com of the file gsiclient2 stored on a GSIFTP server at t0 itso tupi com and request the file The file will be referred to with the tag itso Example 7 19 Adding a file to the cache globus gass cache add t itso r t2 gsiftp t0 home globus gsiclient2 The file is not stored in the cache with the same file name Use the globus gass cache command to retrieve the file as shown in Example 7 20 Example 7 20 Retrieving a file in the cache globus gass cache list r t2 Chapter 7 Using Globus Toolkit for data management 193 URL gsiftp t0 home globus gsiclient2 Tag itso globus gass cache query t itso r t2 gsiftp t0 home globus gsiclient2 It returns the name of the file in the cache home globus globus gass_cache local md5 4e 72 68 e57a109668e83f60927154d812 md5 a6 78 0e 703376a3006db586eb24535315 data You can then invoke it using globusrun as shown in Example 7 21 Example 7 21 Invoking a program from the cache globusrun o r t2 amp executable home globus globus gass_cache 1local md5 4e 72 68 e57a109668e83 60927154d812 md5 a6 78 0e 703376a3006db586eb24535315 data arguments https g0 itso tupi com 10000 Files in the cache are usually referenced with a tag equal to a URL You can use the file name or the tag
388. ta protection should be done on the socket connection Use GLOBUS IO SECURE PROTECTION MODE PRIVATE for encrypted messages GLOBUS IO SECURE PROTECTION MODE SAFE to only check the message integrity and GLOBUS IO SECURE PROTECTION MODE NONE for no protection Example 7 9 Encrypted sockets globus io attr set secure protection mode amp io attr globus io handle t GLOBUS IO SECURE PROTECTION MODE PRIVATE gt globus io attr set secure delegation mode is used to determine whether the process credentials should be delegated to the other side of the connection GLOBUS IO SECURE DELEGATION MODE FULL PROXY delegates full credentials to the server Example 7 10 Delegation mode globus io attr set secure delegation mode amp io attr globus io handle t GLOBUS IO SECURE DELEGATION MODE FULL PROXY gt globus io attr set secure proxy mode is used to determine whether the process should accept limited proxy certificates for authentication Use GLOBUS IO SECURE PROXY MODE MANY to accept any proxy as a valid authentication Example 7 11 globus io set secure proxy mode globus io attr set secure proxy mode amp io attr globus io handle t Chapter 7 Using Globus Toolkit for data management 171 GLOBUS IO SECURE PROXY MODE MANY 7 2 1 globus io example In this example we establish a secure and authenticated communication between two hosts by using the globus io functions We submit from host m0 itso maya com
389. tance the right JDK or interpreter versions may have to be planned and in place Application Server version and standard as well as its capacity may be needed to be considered as well as access requirements and services to be used gt Other applications that are needed to properly run a job have to be in place prior to deployment of the grid application These applications can be compilers databases system services such as the registry under Windows and so on gt Hardware devices that are required for certain jobs to perform their tasks For example requirements for storage measurement devices and other peripherals must be considered when building the application and planning the grid architecture When developing the grid application these prerequisites need to be checked in order to avoid too many restrictions for job execution A large number of restrictions could mean more complicated enablement as well as limiting the number of possible nodes on which the job will be able to run Therefore it is better to restrict such requirements during development of the application such that jobs can run in as generic an environment as possible Chapter 3 Application architecture considerations 55 3 6 Checkpoint and restart capability A job within a grid application may be designed to be launched perform its tasks and report back to the user or grid portal regarding its success or failure In the latter case the same job may be
390. tatic callback does not take any argument So it is impossible afterwards in the callback to refer to the object StartGASSServer 10001 ITSO_GRAM CLIENT does not start the module lets do it if globus module activate GLOBUS GRAM CLIENT MODULE GLOBUS SUCCESS cerr lt lt Cannot start GRAM module 332 Enabling Applications for Grid Computing with Globus exit 2 h the game GAME Current XSIZE YSIZE used to temporary store columns positions evaluation results int s l k toplay used to store human inputs char c 2 The node vector should be initialized with the value of the nodes what is missing here is the globus calls to the globus MDS server to get these values So for the exercise you can use grid info search to find 8 hosts on which you can submit your queries vector lt string gt node ask the broker to find 8 nodes itso broker GetLinuxNodes node 8 variable used in all for loops int i Here we want test the existence of the file as there is no such checking in the ITSO GLOBUS FTP CLIENT class FILE fd fopen SmallBlueSlave r if fd NULL printf Error opening local smallblueslave exit 2 else that fine lets go for FTP we can close fd descriptor because a new one will be opened for each ITSO GLOBUS FTP CLIENT object fclose fd the ITSO CB callback object is used to determine when the transfer has been compl
391. te a new ldap context to hold perform search on filter try ctx new InitialLdapContext env null SearchControls constraints new SearchControls constraints setSearchScope scope constraints setCountLimit sizeLimit constraints setTimeLimit timeLimit store the results of the search in the results variable NamingEnumeration results ctx search baseDN filter constraints displayResults results catch Exception e System err println Failed to search e getMessage finally if ctx null try ctx close catch Exception e The above search method uses the filter to perform an LDAP search A hash table is used to store all of the search information such as the version of LDAP to use the type of security authentication to use and the URL of the LDAP server to query The results returned from the search are stored in a results variable which is passed to the displayResults method shown in Example 6 10 Example 6 10 GridinfoSearch example 3 of 4 DISPLAY RESULTS OF SEARCH private void displayResults NamingEnumeration results throws NamingException if results null return String dn String attribute Attributes attrs Attribute at SearchResult si Chapter 6 Programming examples for Globus using Java 143 use the results variable from search method and store them in a printable variable while results hasMoreElements si SearchResult
392. te void startGassServer try gServer new GassServer 0 gURL gServer getURL catch Exception e System out print n GassServer Error e getMessage gServer registerDefaultDeactivator job output vars oStream new JobOutputStream this eStream new JobOutputStream this JobID String valueOf System currentTimeMillis 158 Enabling Applications for Grid Computing with Globus register output listeners gServer registerJobOutputStream out JobID oStream gServer registerJobOutputStream err JobID eStream System out printIn GassServer started We register listeners to the GASS server so that we can receive the output of the application and also know when the application is finished The method outputChanged will provide the screen output of the application line by line In order to display it we can just reroute it to our screen The method outputClosed tells us that there will be no more output from the application Example 6 35 Interactive GASS example 2 of 3 Method called by the JobOutputListener public void outputChanged String output System out printIn JobOutput output Method called by the JobOutputListener public void outputClosed System out printIn JobOutput OutputClosed Method called by the GRAMJobListener public void statusChanged GramJob job System out print n Job job getIDAsString Status
393. templating creating or porting an application to a grid environment These factors include infrastructure considerations application specific considerations and data management considerations As a result readers should come away with an appreciation for the applicability of a grid environment to their particular application s In the latter part of the book we provide detailed information and examples of using the Globus Toolkit to develop grid enabled applications We provide examples both in C C and in Java This is not intended to be a complete programmers guide or reference manual Instead we focus on many of the issues that an architect or developer needs to be aware of when designing a grid enabled application The programming samples provided in this publication provide the basic techniques required to get you started in the exciting world of application development for grid environments The team that wrote this redbook This redbook was produced by a team of specialists from around the world working at the International Technical Support Organization Austin Center Bart Jacob is a Senior Technical Staff Member at IBM Corp International Technical Support Organization Austin Center He has 23 years of experience providing technical support across a variety of IBM products and technologies including communications object oriented software development and systems management He has over10 years of experience at the ITSO where
394. terate grid proxy init because gsissh supports proxy delegation 7 3 2 globus gass transfer API The gass transfer API is a core part of the GASS component of the Globus Toolkit It provides a way to implement both client and server components gt Client specific functions are provided to implement file get put and append operations gt Server specific functions are provided to implement servers that service such requests Chapter 7 Using Globus Toolkit for data management 187 The GASS Transfer API is easily extendable to support different remote data access protocols The standard Globus distribution includes both client and server side support for the http and https protocols An application that requires additional protocol support may add this through the protocol module interface globus_gass_transfer_request_t request handles are used by the gass_transfer API to associate operations with a single file transfer request The GASS transfer library provides both blocking and non blocking versions of all its client functions 7 3 3 Using the globus_gass_server_ez API This API provides simple wrappers around the globus_gass_transfer API for server functionality By using a simple function globus_gass_server_ez_init you can start a GASS server that can perform the following functions gt Write to local files with optional line buffering Write to stdout and stderr Shutdown callback so the client can stop t
395. terface to stream and datagram style communications It provides wrappers for using TCP and UDP sockets and file I O The Globus Toolkit 2 2 uses a specific handle to refer to a file It is defined as globus_io_handle_t Two functions are provided to retrieve I O handles gt globus io file posix convert which can convert a normal file descriptor into a Globus Toolkit 2 2 handle gt globus io file open which creates a Globus Toolkit 2 2 handle from a file name The Globus Toolkit 2 2 provides I O functions that map the POSIX systems calls and use the Globus Toolkit 2 2 file handle as a parameter instead of the file descriptor gt globus io read globus io write gt globus io writev for vectorized write operations Globus Toolkit 2 2 provides an asynchronous or non blocking I O that uses a callback mechanism The callback is a function given as a parameter to the globus io calls that will be called when the operation has completed By using condition variables the call back can alert the process that the operation has completed gt globus io register read globus io register write gt globus io register writev The Globus Toolkit 2 2 provides functions to manipulate socket attributes and by doing so extends the POSIX system sockets calls In particular it provides a set of functions globus io attr that are used to establish authentication and authorization at the socket level see Example 7 12 on page 173
396. terogeneous data Sources by adding a layer between the databases and the application DB2 SQL XE ue ne federated Wrapper SS S DBMS Bad Oracle T wrapper bm local cache catalog Figure 4 13 Federated databases In a federated database each data source is registered to the federated DBMS along with its wrapper A wrapper is a piece of code dynamic library loaded at runtime by the federated database to access a specific data source The application developer only needs to use a common SQL API like ODBC or JDBO in their applications and to access the federated database The developer also needs to explicitly specify the data source in the federated query Consequently the application must be changed when new data sources are added Currently no federated databases use the Globus Toolkit 2 2 Security Infrastructure GSI to authenticate or authorize the query The application developer needs to manage the authentication process to the database apart from the Globus Security API IBM DB2 Connect provides a solution to transparently access remote legacy systems using common database access APIs like ODBC and JDBC OGSA Database Access and Integration The Open Grid Services Architecture Database Access and Integration OGSA DAI is a project conceived by the UK Database Task Force and is working closely with the Global Grid Forum DAIS WG and the Globus team Chapter
397. the Chapter 2 Grid infrastructure considerations 17 grid The resource management component provides the facilities to allocate a job to a particular resource provides a means to track the status of the job while it is running and its completion information and provides the capability to cancel a job or otherwise manage it In Globus the remote job submission is handled by the Globus Resource Allocation Manager GRAM Globus Resource Allocation Manager GRAM When a job is submitted by a client the request is sent to the remote host and handled by a gatekeeper daemon The gatekeeper creates a job manager to start and monitor the job When the job is finished the job manager sends the status information back to the client and terminates The GRAM subsystem consists of the following elements The globusrun command and associated APIs Resource Specification Language RSL The gatekeeper daemon The job manager Dynamically Updated Request Online Coallocator DUROC YYYY Yy Each of these elements are described briefly below The globusrun command The globusrun command or its equivalent API submits a job to a resource within the grid This command is typically passed an RSL string see below that specifies parameters and other properties required to successfully launch and run the job Resource Specification Language RSL RSL is a language used by clients to specify the job to be run All job submission requests are
398. the Globus Toolkit 2 2 API calls to start and stop the local GASS server The source code of these functions is available in itso gass server C on page 325 We can see in the SmallBlueSlave code source that it reads and writes only on standard input and output channels via cin and cout standard iostream objects It will nevertheless transparently work on remotely stored files thanks to the stdin and stdout keywords in the RSL job description language stdout https lt masternode gt 10000 lt 1localdir gt eval stdin https lt masternode gt 10000 lt 1ocaldir gt GAME Chapter 9 Application examples 267 Where gt stdin is mapped to the GAME file located on the master node and generated by the call to the method ToDisk of the object Current object serialization Another way to proceed would be to use Globus sockets to transfer the serialized object without the need of intermediate files gt stdout is mapped to the eval file located on the master node SmallBlueSlave will write the value of a tested position to this file All the nodes write to eval so all output will be appended to this file SmallBlueSlave also needs a parameter the tested column that will be passed as a parameter to the program via the arguments expression of the RSL job submission string Then SmallBlueSlave uses argv 1 to retrieve this parameter Finally we will use the GridFTP protocol as an example to transfer the SmallBlueSlave executa
399. the actual scheduling of work on the cluster s individual nodes Broker AD Directory Service Th WIE i Lj Portal Scheduler LI Figure 1 4 Scheduler 1 3 5 Data management If any data including application modules must be moved or made accessible to the nodes where an application s jobs will execute then there needs to bea secure and reliable method for moving files and data to various nodes within the grid The Globus Toolkit contains a data management component that provides such services This component known as Grid Access to Secondary Storage GASS includes facilities such as GridFTP GridFTP is built on top of the standard FTP protocol but adds additional functions and utilizes the GSI for user Chapter 1 Introduction 9 authentication and authorization Therefore once a user has an authenticated proxy certificate she can utilize the GridFTP facility to move files without having to go through a login process to every node involved This facility provides third party file transfer so that one node can initiate a file transfer between two other nodes Broker _ MDS Directory Service Lj Portal iud aC d a V i i A GASS Data GSI Mgmt IR Figure 1 5 Data man
400. the solution and the customer The subjects to consider are authentication access control data integrity data confidentiality and key management For a grid application this can be addressed via a Public Key Infrastructure PKI or via the Grid Security Infrastructure GSI as supported by Globus For a grid application the Certificate Authority CA for public keys as well the various encryption mechanisms symmetric or asymmetric can be used During the architecture and design phases one needs to determine which CA and which encryption mechanism to use 84 Enabling Applications for Grid Computing with Globus It has to be assured that the appropriate infrastructure is implemented and reflected in the grid application to be built Hence this is a topic for the qualification scheme see 3 13 2 The grid application qualification scheme on page 69 used at the early stages of a grid project 4 2 Data management techniques and solutions A grid can increase application performance by way of parallelism This implies that a big job must be divided into smaller ones From a data point of view it may be necessary to split the input data and to gather the results after processing The two operations that occur respectively before and after the job submission are called data pre processing and data post processing The data splitting can be triggered each time a job is submitted or it can done one time in advance Similarly the data gathe
401. their application Enabling Applications for Grid Computing with Globus Developing a portal We have mentioned multiple times that the likely user interface to grid applications will be through portals specifically Web portals This chapter shows what such a portal might look like and provides the sample code required to create it The assumption is that the grid specific logic such as job brokers job submission and so on has already been written and is available as Java or C C programs that can simply be called from this portal A few examples of integrating Globus calls with the grid portal are shown Copyright IBM Corp 2003 All rights reserved 215 8 1 Building a simple portal The simple grid portal has a login screen as shown in Figure 8 1 Figure 8 1 Sample grid portal login screen After the user has successfully authenticated with a user ID and password the welcome screen is presented as shown in Figure 8 2 on page 217 216 Enabling Applications for Grid Computing with Globus a D Welcome to Simple Grid Portal Demo Select an application My Application Status My Application Results Logout below and click o 3 Submit Grid This simple grid portal is a demonstration to show how easily you can submit an application to the grid for execution In this demo you will WeatherSimulation be able to GeneProject Submit your application to the grid TestApplication Query your applica
402. these factors as possible or understand that any dependencies will need to be taken into account within the grid infrastructure gt Operating Systems version service level and OS parameter settings that are necessary for execution of the job as well its reliance on certain system Enabling Applications for Grid Computing with Globus services and auxiliary programs such as a registry It is worthwhile to consider whether the grid application will be capable of running its jobs on any node with different operating systems or whether it will be restricted to a single operating system Memory size required by a job may limit the possible nodes on which it can run The available memory size depends not only on its physical presence at a node but also on how much the operating system is capable of granting at run time DLLsthat are to be linked for the execution of the job They either need to be available on the target resource or could possibly be transferred and made available on the resource before the job is executed gt Compiler settings play a role as compiler flags and locations may be different For example subtle differences like bit ordering and number of bytes used for real and integer numbers may cause failures when a job is compiled on a different node or operating system than the one it will eventually be executed on Runtime environment that has to be in place and ready to receive the job for execution For ins
403. ting with Globus 6 Install gsissh as a service cp usr local globus sbin SXXsshd etc rc d init d gsissh chkconfig level 3 gsissh on service gsissh start Note GSIssh can be installed concurrently with a non gsi ssh server However since they both default to using the same port you have to modify the port on which the GSlssh will listen for requests To do this edit etc rc d init d gsissh and assign a value to SSHD_ARGS for example SSHD_ARGS p 24 to listen on port 24 You will then need to specify this port for all gsissh gsiscp and gsisftp commands gsissh p 24 g3 itso guarani com hostname 5 2 4 Job submission skeleton for C C applications To submit a job in a C or C program an RSL string describing the job must be provided The globus gram client API provides an easy API for job submission Two kinds of functions can be used Blocking calls that wait for the completion of the jobs before returning gt Non blocking or asynchronous calls that return immediately and call a callback function when the operation has completed or to inform the main program about the status of the asynchronous operation Chapter 5 Getting started with development in C C 117 callback_func x 1 invokes when job state changes application callback server 4 callback contact url communicates 1 job status change execution node hostname
404. tion but it does provide the necessary functions and framework to create one through the MDS component The broker software will communicate via the LDAP protocol in the Globus Toolkit 2 with the GIIS and GRIS servers The broker can be linked with other information stored in databases or plain files that provide other information such as customer service level agreement resources topology network problems and cost of service This third party data may influence the decisions of what resource to use in conjunction with the technical information provided by default with MDS Enabling Applications for Grid Computing with Globus Woke ddap queries GIIS virtual organization virtual organization Figure 5 3 Working with a broker Using Globus Toolkit tools grid info search as well as 1dapsearch are the shell tools used to query information through the GIIS server The h option allows the user to specify a specific host usually the master GIIS server on top in Figure 5 3 mO in our lab environment The connection to the GIIS can be controlled through GSI security such that a valid proxy certificate needs to be generated before running either of the two commands dluser d1 dluser grid proxy init Your identity 0 Grid 0 Globus OU itso dakota com CN dluser Enter GRID pass phrase for this identity Creating PROV ricrea Done Your proxy is valid until Sat Mar 15 06 55 55 2003 An LDAP query imp
405. tion status Query your results You may now submit an application to the grid Please note this portal is designed for demonstration purposes only Application button Submit Grid Application ad Figure 8 2 Simple grid portal welcome screen From the left portion of the welcome screen the user is able to submit an application by selecting a grid application from the list and clicking Submit Grid Application With the buttons on the top right portion of the screen the user is able to retrieve information about the grid application such as the status and the run results Clicking the Logout button shows the login screen again Let us see how this may be implemented by using an application server such as WebSphere Application Server Figure 8 3 on page 218 shows the high level view of a simple grid portal application flow Chapter 8 Developing aportal 217 login html doPost Login html unsuccessful welcome him doPost Figure 8 3 Simple grid portal application flow The login html produces the login screen where the user enters the user ID and password The control is passed to the Login Servlet with the user ID and password as input arguments The user is authenticated by the servlet If successful the user is presented with a welcome screen with the welcome html file Otherwise the user is presented with an unsuccessful login s
406. tions 45 3 2 Application flow ina grid 45 9 21 Parallel flow vile ia ii eeu ddp te REALEN 46 3 2 2 Serial flow ee 47 3 2 3 Networked flow 0 49 3 2 4 Jobs and SUb jobS LL 50 3 3 Job critena i ai Eee ta Ha sega ga 51 3 9 1c BatcliJOD s su exce eO Qu ER ER NEM Nd 51 3 3 2 Standard application 52 3 3 3 Parallel applications 0 52 3 3 4 Interactive jobs 2 0 i 53 3 4 Programming language considerations 0 53 3 5 Job dependencies on system environment 54 3 6 Checkpoint and restart capability llle 56 33 Job topology c ise ix eb d ee aree CR ale D oet gi 56 3 8 Passing of data input output liliis 57 3 9 TFANSAGHONs lita a teoria CR k e a e teda 58 3 10 Data criteria su incu ened d Ohad ah ee en Da Eg IER 58 3 11 Usability criteria 59 3 11 1 Traditional usability requirements LL 59 3 11 2 Usability requirements for grid solutions 59 3 12 Non functional criteria 61 3 12 1 Software license considerations LL 62 3 12 2 Grid application development 66 3 13 Qualification scheme for grid applications 68 3 13 1 Knock out criteria for grid applications 68 3 13 2 The grid application qualification scheme 69 3 14 Summary ina eee m e qr Am DR m de E Rm HRS 69 Chapter 4 Data management considerations 71 4 1 Datacriteria ouo oi eere mde edd eei enr ds 73 4 1 1 Individual separated data per job
407. to make SmallBlueSlave executable end for i 0 i 8 i rs req amp executable bin chmod count 1 arguments x SmallBlueSlave if job i Submit node i rs req exit 1 for i 0 i 8 i job i gt Wait while true Current Display do cout lt lt 2 cin gt gt C c 1 0 l atoi c while 1 lt 1 1 gt XSIZE Current CanPlay 1 334 Enabling Applications for Grid Computing with Globus Current Play 1 BLACK if Current HasWon 1 BLACK Current Display break h Serialize to disk the Current variable so that it could be used by the GRAM subsystem and transferred on the remote execution nodes Current ToDisk GAME Current Display cout endl remove eval file for each new jobs submission otherwise results will be appended to the same files unlink eval for i 0 i 8 i cout lt lt submission on lt lt node i lt lt endl char tmpc 2 sprintf tmpc d i build the RSL commands rs req amp executable SmallBlueSlave arguments rs reqe tmpc 0 rsl_reqt stdout https rs req hostname rs req 10001 rs req get current dir name rs req eval stdin https rs req hostname rs req 10001 rsl req get current dir name rs req GAME count 1 submit it to the GRAM if Current CanPlay i if job i Submit node i rs req exit 1
408. to process the same data multiple times maybe each run with different parameters However using a cache is not the only solution and considerations such as transfer times and space requirements should be taken into account The Globus Toolkit implements cache mechanisms for files only and not for data files Globus GASS cache provides a C API that provides for the manipulation of the cache The Globus Toolkit also provides the globus gass cache command to manipulate the contents of a local or remote GASS cache Chapter 4 Data management considerations 87 4 2 6 Transfer agent The role of the transfer agent is to provide speed and reliability for files being transferred These files can be Executables scripts or other modules representing the programs that will be run remotely Job dependencies for example dynamic shared libraries Input files gt Output or results files The Globus Toolkit uses the GridFTP protocol for all file transfers This protocol is detailed in GridFTP on page 194 File transfer is built on top of a client server architecture that implies that a GridFTP server must be running on the remote node to be able to transfer a file to the remote host The globus io module and Globus GASS subsystem transparently use the GridFTP protocol Note that the GSlssh transfer tool gsiscp does not use the GridFTP protocol but uses the same encrypted flow transfer used by openSSH http www openssh org 4 2
409. to reflect IBM Microsoft Oracle and other vendors license models in its management IBM Tivoli License Manager is integrated with WebSphere Application Server and available for AIX Solaris and several Microsoft Windows platforms More details about the product are also given on the IBM Software Group Web site at http www ibm com software tivoli products license mgr IBM License Use Management LUM IBM License Use Management LUM in its current version 4 6 6 is designed for technical software license management as it is deployed by most IBM use based software products It is intended to be integrated with any vendor software in order to control use based licensing of the software LUM is available for all Windows platforms AIX HP UX Linux IRIX and Solaris It supports a wide range of C C and Java development environments It can be used in networks with most of the available Web servers Software developers are enabled to reflect various use based license models while integrating LUM APIs in their software products It can be used for monitoring and controlling the use of software in networks Chapter 3 Application architecture considerations 65 More details are found on the IBM software group Web site at http ww ibm com software is 1um Platform Global License Broker Among the various ISVs that offer grid software products Platform shows a special grid oriented license management feature named Platform Glo
410. tso maya com objectclass You should see the following in the output dn dc itso maya dc com objectclass top objectclass GlobusTop dn rc test dc itso maya dc com objectclass top objectclass GlobusReplicaCatalog objectclass GlobusTop 7 6 Summary The Globus Toolkit 2 2 does not provide a complete data grid solution but provides all of the components of the infrastructure to efficiently build a secure and robust data grid solution Major data grid projects are based on or use the Globus Toolkit and have developed data grid solutions suited to their needs Chapter 7 Using Globus Toolkit for data management 213 214 The Globus Toolkit 2 provides two kinds of services regarding data grid needs gt For data transfer and access GASS which is a simple multi protocol file transfer It is tightly integrated with GRAM GridFTP which is a protocol and client server software that provides high performance and reliable data transfer gt For data replication and management Replica Catalog which provides a catalog service for keeping track of replicated data sets Replica Management which provides services for creating and managing replicated data sets All these services should not be considered as a complete and integrated Data Grid solution but they provide APIs and components to application developers to build a data grid solution that will fit their expectation and that will integrate easily with
411. tso tupi com home globus storage uc means URL Constructor and is the attribute used in the LDAP directory to store the location URL 2 Check the size attribute for the file file2 globus replica catalog password password logicalfile file2 list attributes size You receive size 200000 7 5 3 Installation The installation process is explained at http www globus org gt2 replica html Chapter 7 Using Globus Toolkit for data management 211 It consists of the following steps 1 Addanewschema that defines objects manipulated for replica management It can be downloaded from http ww globus org gt2 replica schema txt Copy this file to GLOBUS LOCATION etc openldap schema replica schema Edit GLOBUS_LOCATION etc openidap slapd conf to reflect your site s requirements for all bolded entries See slapd conf 5 for details on configuration options This file should NOT be world readable include usr local globus etc openldap schema core schema include usr local globus etc openldap schema repl ica schema pidfile usr local globus var slapd pid argsfile usr local globus var slapd args Heed ee EH He Eee a Ee Ee ee a a a a ae a a a ae a a ae a ee a a PE ldbm database definitions THHHHHHHHHHHHHHHHHEHHHHHHHHEHHHHHHHHERHHHHHHHHHHHBHHBHHHE database ldbm suffix dc itso maya dc com rootdn cn Manager dc itso maya dc com rootpw globus directory usr local globus var openldap ldbm index objectClass e
412. tus of the globus calls and displays the Globus error message The t variable needs to be defined before kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk define _ a t a if t GLOBUS_SUCCESS cerr lt lt globus object printable to _string globus_error_get t kkkkxkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk This function is used to check the validity of the local credentials probably generated by gatekeeper or gsi ssh server kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk bool getCredential gss cred id t credential_handle OM uint32 major status OM uint32 minor status major status globus gss assist acquire cred amp minor status GSS C INITIATE or GSS C ACCEPT credential handle if major status GSS S COMPLETE return false else return true kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Here is the main program create a socket connect to the server and say Hello _ macro is used to check the error code of each Globus function and display the Globus Error message The first argument will be used to indicate the server to connect to for example http m0 itso maya com 10000
413. ude itso_cb h define _ a r a if r GLOBUS_SUCCESS cerr lt lt globus_object_printable_to_string globus_error_get r exit 1 define MAX_BUFFER_SIZE 2048 define SUCCESS 0 f E EFAAAAAARA AAA AAA AAA AA ARA AAA KR ERK KEK EKER KK EKER AAA AA ARA KARA RE KER EKER class ITSO GLOBUS FTP CLIENT public ITSO CB FILE fd globus_byte_t buffer MAX_BUFFER_SIZE globus_ftp_client_handle_t handle public ITSO_GLOBUS_FTP_CLIENT char char ITSO GLOBUS FTP CLIENT void StartTransfer void Transfer globus byte t globus size t amp globus off t8 h endif ifndef ITSO_ITSO_GLOBUS_FTP_CLIENT_H define ITSO_ITSO_GLOBUS_FTP_CLIENT_H include lt cstdio gt include lt iostream gt include globus_ftp_client h include itso_cb h define a r a if r GLOBUS_SUCCESS cerr lt lt globus object printable to string globus error get r exit 1 define MAX_BUFFER_SIZE 2048 define SUCCESS 0 f EB RA ARA AAA AAA AA RAR AAA ERK EKER KR AR AA RARA AAA AA RA AAA RK KERR KERR EERE KEKE KEK class ITSO GLOBUS FTP CLIENT public ITSO CB FILE fd globus byte t buffer MAX BUFFER SIZE globus ftp client handle t handle 312 Enabling Applications for Grid Computing with Globus public ITSO_GLOBUS_FTP_CLIENT char char ITSO_GLOBUS_FTP_CLIENT void StartTransfer void Transfer globus byte t globus_size_t amp globus_off_t amp h endif itso globus ftp c
414. unts of data there can be arguments that specify the name of a data file or other data source Data store of any kind such as data files in the file system local or on a LAN or WAN or records in a database a data warehouse or other storage system that is available These data stores can be used for input as well as output of data given that the required access rights are granted to the job The transfer of data in can be done anytime before the job executes and likewise the output data could be read anytime after the job completes therefore providing flexibility for data movement operations gt Message queues like those provided by WebSphere MQSeries are well suited to be used for asynchronous tasks within a grid application especially when guaranteed delivery of the data provided to the job and generated by the job is of high importance A job can access the data queues in various ways normally using specific APIs for putting or getting data as well as for polling the queue for data waiting for processing In an environment where message queueing servers are already installed this type of data passing may be desirable gt System return value is a corresponding case to the CLI and normally a way a batch job or any CLI invoked program will return data or at least status information about how the job ended This indicates to the grid server or grid portal the status of the individual job and requires appropriate management The
415. valid input String title Invalid Input out printIn html out printIn head out printIn title title lt title gt out printIn head out println body bgcolor cfd09d text 000099 gt out println hl align center gt title lt h1 gt out printIn body out printIn lt htm1 gt private void sendResult String list Chapter 8 Developing a portal 241 int size list length for int i 0 i lt size i String s list i out printIn s lt br gt System out printIn s s trace end for public String doProxy String cmdResult null String subCmd echo mOuser grid proxy init pwstdin try String cmd bin su c subCmd mOuser cmdResult doRun cmd catch IOException e System out println doProxy e return cmdResult public String doSubmit String mdsHost String appName String cmdResult null String subCmd globus job submit mdsHost stage appName try String cmd bin su c subCmd mOuser cmdResult doRun cmd catch IOException e System out println doSubmit e return cmdResult 0 public String doGetStatus String jobId String cmdResult null String subCmd globus job status jobId try String cmd bin su c subCmd mOuser cmdResult doRun cmd
416. ver unsigned long server ez opts 0UL Files openfor writing will be written a line at a time so multiple writers can access them safely server ez opts GLOBUS GASS SERVER EZ LINE BUFFER URLs that have character will be expanded to the home directory of the user who is running the server server ez opts GLOBUS GASS SERVER EZ TILDE EXPAND URLs that have user character will be expanded to the home directory of the user on the server machine server ez opts GLOBUS GASS SERVER EZ TILDE USER EXPAND get requests will be fullfilled server ez opts GLOBUS GASS SERVER EZ READ ENABLE put requests will be fullfilled server ez opts GLOBUS GASS SERVER EZ WRITE ENABLE for put requets on dev stdout will be redirected to the standard output stream of the gass server server ez opts GLOBUS GASS SERVER EZ STDOUT ENABLE for put requets on dev stderr will be redirected to the standard output stream of the gass server server ez opts GLOBUS GASS SERVER EZ STDERR ENABLE Appendix B C C source code for examples 325 put requests to the URL https host dev globus gass client shutdown will cause the callback function to be called this allows the GASS client to communicate shutdown requests to the server server ez opts GLOBUS GASS SERVER EZ CLIENT SHUTDOWN ENABLE Secure char scheme https unsecure char scheme http globus gass transfer listenerattr
417. welcome html script is provided in Example 8 3 on page 223 Tip The application servlet is associated with welcome html with following statement FORM name form method post action Application gt Tip The application selection list is produced by the nested statements lt SELECT size 4 name appselect gt lt OPTION value weather gt WeatherSimulation lt OPTION gt lt OPTION value gene gt GeneProject lt OPTION gt lt OPTION value test gt TestApp lt OPTION gt OPTION value demo selected gt DemoApp lt OPTION gt lt SELECT gt 222 Enabling Applications for Grid Computing with Globus Example 8 3 Simple grid portal welcome html lt DOCTYPE HTML PUBLIC W3C DTD HTML 4 01 Transitional EN gt lt HTML gt lt HEAD gt lt page language java contentType text html charset IS0 8859 1 pageEncoding IS0 8859 1 gt META http equiv Content Type content text html charset IS0 8859 1 gt lt META name GENERATOR content IBM WebSphere Studio gt lt META http equiv Content Style Type content text css gt lt LINK href theme Master css rel stylesheet type text css gt lt TITLE gt welcome jsp lt TITLE gt lt HEAD gt lt BODY gt lt FORM name form method post action Application gt H1 align center gt Welcome to Grid Portal Demo lt H1 gt lt TABLE border 1 width 718 height 262 gt lt TBODY gt lt TR gt lt TD width 209 height 37 gt lt TD gt lt T
418. wing Web site http www gridforum org 4 GP ogsap2p htm 4 2 9 Sandboxing For performance reasons runtime files tend to be stored on the local storage where the job will use them Programs and data files are stored on a remote site and copied to local disks when needed The performance of the LAN environment may be good enough so that a network file system could provide the needed bandwidth and therefore could avoid the overload of data transfer This becomes not true in a WAN environment or if the jobs need to work repeatedly on the same data sets A sandbox provides a temporary environment to process data on a remote machine and imited access to the resources of the node This way the job execution cannot interfere with normal processes running on this node Data are copied into this sandbox The sandbox can be encrypted so that any other applications normally running on the node could not access the job data sandbox C job D environment e network system resource data space Figure 4 7 Sandboxing Globus Toolkit also provides globus gass cache commands to manipulate the contents of a local or remote GASS cache Each entry in a GASS cache consists of a URL local file name a list of tags and a reference count for each tag When the last tag for a URL is removed the local file is removed from the cache The cache directory is actually a directory located in the globus
419. x servlet ServletException e System out printIn e catch java io IOException e System out printIn e Chapter 8 Developing a portal 231 8 2 Integrating portal function with a grid application This section describes some techniques for integrating the portal with a grid enabled application 8 2 1 Add methods to execute the Globus commands The simplest and most obvious integration is to be able to launch or execute Globus commands via the Web interface From a Java servlet you may need to launch Globus commands written in C Let us see how this is accomplished Running non Java commands from Java code Our portal code is written in Java If the grid commands and the Globus commands are also Java classes then this section can be skipped There are two possible ways to do this One way is to use the Java native method which can be difficult to implement The second way is to use the exec method of the Runtime class This method is easier to implement and our choice used in the sample code Either option will lose platform independence The sample code in Example 8 5 shows how to execute the grid commands and Globus commands from the Web portal Java code Tip The method of running non Java commands from Java code is Proc p Runtime getRuntime exec cmd Tip Below is the method of properly passing parameter inputs or sub commands to the non Java command The exec method has trouble handling a single string pas
420. y to the application server We use the ITSO GLOBUS FTP CLIENT class to do the task Note that we use the local directory to perform the task In a real case example a storage server would be used instead of a local directory gt globus url copy gsiftp storage server commoncpp2 1 0 8 tar gz gsiftp application server commoncpp2 1 0 8 tar gz ERA A AA AA AAA A AAA AAA AIR AAA AA AAA RA KKK ARA AA AAA AAA AAA e He ke AAA GLOBUS_URL source destination source setURL gsiftp m0 tmp commoncpp2 1 0 8 tar gz string dst dst gsiftp node commoncpp2 1 0 8 tar gz destination setURL dst globus module activate GLOBUS GASS COPY MODULE ITSO GASS TRANSFER transfer transfer Transfer source destination transfer Wait globus module deactivate GLOBUS GASS COPY MODULE f EBRAICA AA AAA A AAA AAA AIAR AAA ERK ERK AAA AA RA AAA AAA AAA KEKE ERK K In this section we submit the compilation of the dynamic libray The script Compile that must be in the current directory is transferred to the remote host and executed The result is the installation of the CommonC toolkit in the tmp directory of the user under which the script was executed globus in the lab environement of the redbook f EBREA AA AA AAA AAA AA AAA KERR KR RR KR ERK ARA ARA AA AAA ARA KERR REE He used to store the RSL commands string rs req 344 Enabling Applications for Grid Computing wit
421. y interested in the resources running the Linux operating system This can be expressed by the following LDAP query amp Mds 0s name Linux Mds Host hn Then we can submit the query as shown in Example 5 14 on page 121 Example 5 19 Submitting the LDAP query string filter amp Mds Os name Linux Mds Host hn if ldap_search_s ldap_server base dn LDAP SCOPE SUBTREE const cast char filter c str attrs 0 amp reply LDAP SUCCESS ldap perror ldap server ldap search 128 Enabling Applications for Grid Computing with Globus ldap unbind ldap server exit 1 The result of the query is a set of entries that match the query Each entry is itself a set of attributes and their values The Idap first entry and Idap next entry functions allow us to walk the list of entries Idap first attribute and ldap next attribute allow us to walk the attribute list and Idap get values is used to return their value Example 5 20 Retrieving results from Globus MDS LDAPMessage reply LDAPMessage entry vector lt Host gt nodes for entry ldap_first_entry ldap_server reply entry GLOBUS NULL entry ldap next entry ldap server entry cout lt lt end lt lt ldap get dn ldap server entry lt lt end BerElement ber char values char attr char answer GLOBUS_NULL string hostname int cpu for attr ldap_first_attribute ldap_server entry amp
422. y setUseThirdPartyCopy true ucopy setSourceAuthorization srcAuth ucopy setDestinationAuthorization dstAuth System out print n Start Copy ucopy copy System out print n All done catch Exception e System out printIn Error e getMessage public static void main String args URLCopy u new URLCopy u ucopy 6 7 GASS The GASS API can be used to send or retrieve data files or application output When for example submitting a job in batch mode the result of the job can be picked up using the GASS API or any standard binary tool provided by the Globus Toolkit When using interactive job submission the GASS API can be used to retrieve the output of an application by redirecting standard out and standard error to the client Chapter 6 Programming examples for Globus using Java 155 These two examples will show how to submit a job and retrieve the results GASS Batch gt GASS Interactive 6 7 1 Batch GASS example The following examples are of batch GASS Example 6 30 Batch GASS example 1 of 4 import org globus gram Gram import org globus gram GramJob import org globus gram GramJobListener import org globus io gass server GassServer import org globus util deactivator Deactivator Example of using GRAM amp GASS in batch mode public class GASSBatch implements GramJobListener private GassServer gServer null private String gURL null private String
423. y stored in a Mass Storage System GDMP C APIs for clients provide four main services Subscribing to a remote site for obtaining information when new files are created and made public gt Publishing new files and thus making them available and accessible to the grid Chapter 4 Data management considerations 97 gt Obtaining a remote site s file catalog for failure and recovery gt Transferring files from a remote location to the local site Organization maya Storage Element EN Site maya Organization tupi local storage d copied locally Storage Elemen gridftp transfer Site tupi Figure 4 12 File replication in a data grid between two organizations GDMP is available at http project gdmp web cern ch project gdmp 4 2 14 Database solutions for grids As covered in 4 2 2 Databases on page 86 the Globus Toolkit V3 should provide a set of services to access data stored in databases and several projects that are ongoing such as SpitFire in EU DataGrid and the UK Database Task Force can already be tested Until these solutions become ready several commercial solutions can help to enable database access in a grid application 98 Enabling Applications for Grid Computing with Globus Federated databases A federated database technology provides a unified access to diverse and distributed relational databases It provides transparency to he
424. ystems are usually suitable for cluster needs where a cluster is defined as a set of nodes interconnected by a high performance switch or in LAN environment Nevertheless Global file systems are often unique to one organization and therefore cannot be easily shared by multiple organizations Network File System NFS NFS is almost universally used in the Unix world and is the de facto standard for data file sharing in a LAN environment NFS V2 supports files up to a maximum size of 2 GB NFS V3 improves file transfer performance and gets rid of some of the NFS V2 limitations 64 bit file support write caching NFS uses the udp protocol but can also use tcp protocol as it does by default under AIX NFS V4 is the emerging standard for UNIX file system access It will be supported in the AIX operating system and in the forthcoming Linux 2 6 kernel NFS V4 includes many of the features of AFS and DFS NFS V4 uses strong Kerberos V5 security and Low Infrastructure Public Key and it should also 90 Enabling Applications for Grid Computing with Globus perform on a WAN environment as well as it does on a LAN by using file caching and minimizing the number of connections needed for read and write operations NFS V4 appears to be a good alternative to AFS and DFS file systems and could be used in a grid environment where a cost effective shared file system is required For more information on NFS Version 4 Open Source Reference Implementat

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