The DDS User Manual
Contents
1. 9 1 Tutorial 1 This tutorial demonstrates how to deploy a simple topology of 2 types of tasks TaskTypeOne and TaskTypeTwo By default there will be deployed one instance of TaskTypeTwo and 5 instances of TaskTypeOne Additionally TaskTypeTwo subscribes on key value property from TaskTypeOne which name is TaskIndexProperty Once TaskTypeTwo receives values of TaskIndexProperty from all TaskTypeOne it will set the ReplyProperty property Number of instances can be changed in the topology file tutoriall topo xml using instances option of TaskTypeOne Please note that number of worker nodes in the SSH plugin configuration file tutoriall_hosts cfg has to be changed accordingly After DDS is installed the tutorial can be found in DDS LOCATION tutorials tutoriall The source code of tasks is located in DDS_SRC_DIR dds tutorials dds tutoriall Files of the tutorial task type one executable of the task TaskTypeOne task type two executable of the task TaskTypeTwo tutoriall topo xml a topology file tutoriall hosts cfg a configuration file for DDS SSH plug in 9 1 1 Usage Before running the tutorial make sure that 1 Default working directory tmp dds wn test must exist before running the tutorial The directory can be changed in tutoriall_hosts cfg 2 SSH passwordless access to the localhost is required cd DDS LOCATION tutorials tutoriall dds server start s dds submit r ssh ssh rms cfg tutoriall hosts cfg d2. Attribute reachable access type Description String with minimum length of 1 character Description Defines identificator ID for topology propertiy task collection and group ID has to be unique within its scope i e ID for tasks has to be unique only for tasks lt topology id myTopology gt Use optional Default true Tags exe env Restrictions truelfalse Description Defines if executable or script is available on the worker node lt exe reachable true gt app 1 lt exe gt lt env gt env1 lt env gt Use optional Default 1 Tags group Restrictions unsigned integer 32 bit which is more or equal to 1 Description Defines multiplication factor for group lt exe reachable true gt app 1 lt exe gt lt env gt env1 lt env gt Use optional Default readwrite Tags id Restrictions readlwritelreadwrite Description Defines access type from user task to properties lt id access read gt propertyl lt id gt Use required 15 Topology Attribute Description Tags hostPattern Restrictions hostnamelwnname Description Defines the type of the host pattern hostPattern type wnname value wn2 gt 16 7 How to Start 7 1 Environment In order to enable DDS environment you need to source the DDS_env sh script The script is located in the directory where you installed PoD cd DDS INSTALLATION source DDS_env sh 7 2 Server Use the dds
3. Description Declares a pattern of the host name lt hostPattern type hostname value gsi de gt Parents topology Children exe env requirement properties Attributes id Description Declares a task lt decltask id task1 gt lt exe reachable true gt appl 1 n lt exe gt env reachable false gt envl lt env gt lt requirement gt requirement1 lt requirement gt lt properties gt id access read gt propertyl lt id gt lt id access readwrite gt property2 lt id gt lt properties gt lt decltask gt Parents topology Children task Attributes id Description Declares a collection declcollection id collection1 gt task taskl task task taskl task declcollection Parents collection group Children No Attributes No Description Specifies the unique ID of the already defined task lt task gt task1 lt task gt 12 Topology Tag collection group main exe required Description Parents group Children No Attributes No Description Specifies the unique ID of the already defined collection lt collection gt collectionl lt collection gt Parents main Children task collection Attributes id n Description Declares a group group id groupl n 10 gt lt task gt task1 lt task gt lt collection gt collectionl lt collection gt lt collection gt collection2 lt collection gt lt group gt P
4. Resource definitlon ct Tai ens 30 111 List of Tables 4 1 DDS configuration variables ro eter tero Dee eto ge REX E EC E FU PERS RED pa R Ea 4 6 1 Topology XML tags iet A it Peg R 10 6 2 Topology SA eret PE EH OEE EE FRE ERR case us sucms MEER ERA PE Rr ER dye STES EE UNE 14 11 1 DDS s SSH plug in configuration fields ooooncnncnnccnnncnnccnnccnnconnconnconnconnconnconncnnnnnnncnnronaroncnnos 30 List of Examples 6 1 A topology file example 11 1 An example of an SSH plug in configuration file ocooocnnccnnccnnncnnconoconccnnccnnccnnccnnccnnconncnnncnnnos 1 Introduction 1 1 The Dynamic Deployment System 1 2 Features 2 Requirements 2 1 Server Ul DDS Ul Server WN run on Linux and Mac OS X General requirements Incoming connection on dds commander port configurable e a C 11 compiler cmake 2 8 11 or higher BOOST 1 54 or higher built by a C 11 compiler with C 11 enabled shell BASH Additional requirements for SSH plug in A public key access or password less via ssh agend for example to destination worker nodes 2 2 Workers General requirements Outgoing connection on dds commander s port configurable This is required by dds agent to be able to connect to DDS commander server shell BASH 3 Download 3 1 Download location Please use DDS s Download page to get the latest version and all other versions of DDS 3 2 DDS Versio
5. Topology end cts rrr E Rr RC NR PR ages CR SEE coed ASSERERE REIR ERR E RR LIRE 8 631 Topology Meno alte p gine iiM 8 6 2 Topology file example 1 rette ero tese t E RICE ee PEU ET eve e E cob sd pos 8 6 3 Topology XML tag reference 20 0 0 cece cece cece EEEE e Hem He mee hen hen he rre rene ree 10 Te HOW to Start so rer RE aE a EEG eevee dan e REESE AER E PIREER OP RR REPERI EOM EPIS 17 VEI REESE ter eri 17 A E 17 7 3 Deploy Agents nion hri II nee ea d Sages re oases 17 7 3 1 Deploy Agents using SSH plug in 20 0 cece cece HH meme 17 7 4 Check availability of Agents 2 0 0 0 cece cece cece a eece cece cena e e m e mH HI emen he ere ree rene 17 TS Set Topology O ptas 17 7 6 Activate Agents 2 ote eer A e eee puer eese eee demie teda 18 So HOW tor Test cda Ere ED ER Ye PA EPA GO PARAR PER ERE ERE PINE P ATRERERESRR EET ES E ASS 19 Sil A p 19 Or Tutorials ii as 20 OD A NN 20 9 1 1 USADO id tro E 20 91 2 A OA 20 10 Command line Interface noise e REP PI sass Urra E R Tn Pape perdes 21 AOS 22 dds commandet coelo rr Pr C ERR VERE Ea ao REI ASS PEAR EE E A ER RET RUE 23 dds usersdetaults rRNA Eos e VN eerie EE HM 24 dds Est PO ID ee IET ts 25 UASD A AA II ERN SEE EARN A tea 26 dd RAPAE EEE AAA E NER RB EE RORERETER FQ TC REREERUER 27 dds topology cita deis 28 dds asent cimd veranos EE 29 11 SSH pl PSP 30 1 1 1
6. a shared installation then please see the Section 4 5 Step 5 DDS shared Installation as well 4 5 Step 5 DDS shared Installation TODO 5 Configuration TODO 6 Topology The definition of the topology by the user has to be simple and powerful at the same time Therefore a simple and powerful so called topology language has been developed The basic building block of the system is a task Namely a task is a user defined executable or a shell script which will be deployed and executed by DDS on a given Resource Management System In order to describe dependencies between tasks in a topology we use properties In run time properties will be turned into simple key value pairs DDS uses its key value propagation engine to make sure that once property is set by one task it will be propagated to other depended tasks DDS treats values of properties as simple strings and doesn t do any special treatment preprocessing on them So basically tasks can write anything into the values of properties 256 char max Any of depended tasks can set properties Anytime property is set it will be propagated to other depended tasks see for details TODO key value propagation Tip For example if one task needs to connect with another task they can have the same property A server task can store its TCP IP port and host in the property Once the property set DDS will notice that and propagate it to other tasks Tasks can be gro
7. options to specify non default location of the DDS configuration file By default the command uses DDS DDS cfg key arg Gets a value for the given key from the DDS user defaults wrkpkg Shows the full path of the worker package The path must be evaluated before use wrkscript Shows the full path of the worker script The path must be evaluated before use rms sandbox dir Shows the full path of the RMS sandbox directory It returns server sandbox dir if it is not empty otherwise server work dir is returned The path must be evaluated before use user env script Shows the full path of user s environment script for workers if present The path must be evaluated before use server info fil Shows the full path of the DDS server info file The path must be evaluated before use 24 Command line interface Name dds submimt submits and activates DDS agents UNIX Linux OSX Synopsis dds submit h help l v version l c config arg r rms arg ssh rms cfg arg Description The command is used to submit DDS agents to allocate resources for user tasks Once enough agents are online use the dds topology command to activate the agents i e distribute user tasks across agents and start them Options h help Shows usage options v version Shows version information c config arg Only for advanced users This options can be used to specify the location of the dds submit c
8. using the group tag It has a required attribute id which is used to uniquely identify the group and optional attribute n which defines multiplication factor for the group In the example group consists of one task task and two collections collection and collection2 group2 consists of one collection collection1 6 3 Topology XML tag reference Table 6 1 Topology XML tags Tag Description topology Parents No Children property task collection main 10 Topology Tag var property Description Attributes id Description Declares a topology lt topology id myTopology gt oso Derio 0 casks properties collections and groups o od topology Parents topology Children No Attributes id value Description Declares a variable which can be used inside the topology file as variable name var id varl value valuel gt SA NA A UNAS Parents topology Children No Attributes 1d Description Declares a property property id propertyl property id property2 gt declrequirementParents topology hostPattern Children hostPattern Attributes id Description Declares a requirement for tasks and collections lt declrequirement id requirementi hostPattern value gsi de gt lt declrequirement gt Parents declrequirement Children no 11 Topology Tag decltask declcollection task Description Attributes value type
9. ROUP NAME ID of the parent group DDS COLLECTION NAME ID of the parent collection if any DDS TASK NAME ID of the task In the example above we define 2 properties property and property2 As you can see the property tag is used to define properties id attribute is required and has to be unique for all properties Requirements is another nice feature of DDS Requirements is a way to tell the DDS that a task or collection has to be deployed to a particular computing node As of now only host name or worker node name which is defined in the SSH configuration file requirements are supported Requirements are defined using declrequirement tag id attribute is required and has to be unique for all requirements Pattern of the host name is defined using hostPattern tag which attribute value can be either a full host name or a regular expression which matches the required host name t ype defines the type of the host Pattern Can be either hostname if the requirement is defined based on the host name or wnname if the requirement is defined based on the SSH worker node name In the next block we define tasks For this the decltask tag is used A task must also have the id attribute which is required and has to be unique for all declared tasks The requirement element is optional and specifies the already declared requirement for the task The exe element defines path to executable The path can include program options even options with quotes DDS wi
10. The DDS User Manual The DDS User Manual Table of Contents 1 Introduction tl privata le e EN UR EAD ER tetas 1 1 1 The Dynamic Deployment System ooooccnnconoconcconcconccnnonnncnnncnn cono ronnoronconncrnncnnncnnnrnnrnnnrcnncnnn 1 1 2 Features err age rr PR ROER CERES AE PRA PER ORE OE ade E NACA NER RS REEF CERE EE FER CER S ERERER 1 2 REQUIEM A A ERE Mi I NES 2 POENIS EE 2 22y WOETKEIS ete rer there Se Raa dei eese Snes dee porcos etus ve dee o v sa eye Eu E Pe nee P eee Sed 2 3 Download viii ibi RARA ao PAT Es EFE REP AS AE A SES EENIA E PRRE ERE PERSE EYES E pa SPAA 3 31 Download location erre e Ree eee IEEE ve yen eeu Vu er eee ee IEEE ea ENSURE ER eee 3 3 2 DD5 Version Number Scheme ce Pe tek Ro ER TREE ESCAPE E tees 3 4 E M EN 4 Alle Step 31 Get the SOULCE ss iion peer ER eer o Cn Sb e re REPE Or HERE e ERR CORE SEPT SERE AVETS 4 4 1 1 from DDS git repository 2 0 cece cee III em mhem hen hent rentrer 4 4 1 2 from DDS source tarball 2 toe tt Pte e PEOR EYE E CRAS ER ER e ERREUR e 4 4 2 Step 42 Configure the source e a a Ee eese side eerie dese eter pesi eee Ens Pet E Du ase 4 4 3 Step 43 Build and install ier erret ERI ee E Pee dye Pert Rss 3 4 4 Step 44 DDS Environment ee ete ette ea eee REIHE UE eran asii 5 4 5 Step 45 DDS shared Installation 235 cass tet ertt terrere Ete Fes Rer RR SET sacas 6 2t Configuration o eee ree e Sek owes e tre AA ese eter eee ee eee eon 7 6
11. arents topology Children task collection group Attributes id Description Declares a main group lt main id main gt lt task gt task1 lt task gt lt collection gt collectionl lt collection gt group id groupl n 10 gt lt task gt task1 lt task gt lt collection gt collectionl lt collection gt lt collection gt collection2 lt collection gt lt group gt lt main gt Parents decltask Children No Attributes reachable Description 13 Topology Tag env optional properties optional id required Description Defines path to the executable or script for the task lt exe reachable true gt appl 1 n lt exe gt Parents decltask Children No Attributes reachable Description Defines the path to script that has to be executed prior to main executable lt env reachable false gt setEnv sh lt env gt Parents decltask Children id Attributes No Description Defines a list of dependent properties lt properties gt lt id gt propertyl lt id gt lt id gt property2 lt id gt lt properties gt Parents properties Children No Attributes access Description Defines an ID of the already declared property lt id gt propertyl lt id gt Table 6 2 Topology XML attributes Attribute id Description Use required Default No Tags topology property decltask declcollection group main Restrictions 14 Topology
12. but each user gets its own DDS instance and can t disturb other users Each user can tune DDS by changing the DDS user defaults configuration in SHOME DDS DDS cfg 4 1 Step 1 Get the source 4 1 1 from DDS git repository git clone https github com FairRootGroup DDS git DDS master 4 1 2 from DDS source tarball Unpack DDS tarball tar xzvf DDS X Y Z Source tar gz Tar will created a new directory DDS X Y Z Source where X Y Z represents a version of DDS 4 2 Step 2 Configure the source Change to the DDS source directory cd DDS X Y Z Source You can adjust some configuration settings in the BuildSetup cmake bootstrap file The following is a list of variables Table 4 1 DDS configuration variables Variable Description CMAKE INSTALL PREFIX Install path prefix prepended onto install directories default SHOME DDS DDS Version CMAKE BUILD TYPE Set cmake build type Possible options are None Debug Release RelWithDebInfo MinSizeRel default Release BUILD DOCUMENTATION Build source code documentation Possible options are ON OFF default OFF Installation Variable Description BUILD_TESTS Build DDS tests Possible options are ON OFF default OFF Now prepare a build directory for an out of source build and configure the source mkdir build cd build cmake C BuildSetup cmake y i If for some reason for example a missing dependency configuration failed After you get the issu
13. ds topology set tutoriall topo xml dds topology activate 9 1 2 Result To check the result change to tmp dds wn test If the default setup was used then there will be WN directories located wn wn 1 wn 2 wn 3 wn 4 wn 5 DDS catches output of tasks and saves it in log files under names task name date time outlerr log For exmaple TaskTypeOne 2015 07 16 11 44 42 6255430612052815609 out log 20 10 Command line interface Command line interface Name dds server wraps to manage DDS commander server daemon UNIX Linux OSX Synopsis dds server start s restart s stop status Description Using this command users can start stop restart status DDS commander server The command is actually a wrapper for the dds commander command DDS commander server which become a daemon process when started Options start Start DDS commander server At the server start DDS will detect availability of DDS WN bin packages and download them from the DDS repository if they are missing Users can provide an additional parameter s the parameter can be specified with start and restart When the parameter is provided DDS will check availability of a binary package compatible with the local system only To build a binary package for the local system just issue make j wn bin make j install restart Restart DDS commander server stop Stop DDS commander server status Re
14. e fixed right before starting the cmake command it is recommended to delete everything in the build directory recursively This will guaranty a clean build every time the source configuration is restarted 4 3 Step 3 Build and install Issue the following commands to build and install DDS make j make install Installation Prefix Please note that by default DDS will be installed in HOME DDS X Y Z where X Y Z is a version of DDS However users can change this behavior by setting the install prefix path in the bootstrap script BuildSetup cmake Just uncomment the setting of CMAKE_INSTALL_PREFIX variable and change dummy MY_PATH_HERE to a desired path y WN package Users have a possibility to additionally build DDS worker package for the local platform In case if you have same OS types on all of the target machines and don t want to use WN packages from the DDS binary repository just issue make j wn bin make install the commands will build and install a DDS worker package for the given platform 4 4 Step 4 DDS Environment In order to enable DDS s environment you need to source the DDS env sh script Change to your newly installed DDS directory and issue cd DDS INSTALL DIRECTORY source DDS env sh You need to source this script every time before using DDS in a new system shell Simplify it by sourcing the script in your bash profile Installation Now the installation is done But if you were preparing
15. ion factors are also defined in main block 6 2 Topology file example Example 6 1 A topology file example lt topology id myTopology gt var id appNameVar value appl 1 n taskIndex taskIndex collectionIndex co Topology lt var id nofGroups value 10 gt property id propertyl gt lt property id property2 gt lt declrequirement id requirement1 gt lt hostPattern type hostname value gsi de gt lt declrequirement gt lt decltask id task1 gt lt requirement gt requirement1 lt requirement gt exe reachable true gt S appNameVar lt exe gt lt env reachable false gt envl lt env gt lt properties gt id access read gt propertyl lt id gt id access readwrite gt property2 lt id gt lt properties gt lt decltask gt lt decltask id task2 gt lt exe gt app2 lt exe gt lt properties gt lt id access write gt propertyl lt id gt lt properties gt lt decltask gt lt declcollection id collection1 gt lt requirement gt requirement1 lt requirement gt lt tasks gt lt id gt task1 lt id gt lt id gt task2 lt id gt lt id gt task2 lt id gt lt tasks gt lt declcollection gt lt declcollection id collection2 gt lt tasks gt lt id gt task1 lt id gt lt id gt task1 lt id gt lt tasks gt lt declcollection gt lt main id main gt lt task gt task1 lt task gt lt collection gt collectionl lt c
16. ll automatically pars the path and extractor program options in runtime The exe tag has an optional attribute reachable which defines whether executable is available on worker nodes If it is not available then DDS will take care of delivering it to an assigned worker in run time In case when there is a script that for example sets environment has to be executed prior to main executable one can specify it using the env element The env tag also have reachable attribute If a task depends on some properties this can de specified using the properties tag together with a list of id elements which specify ID of already declared properties Each property has an optional access attribute which defines whether user task will read read write write or both read and write readwrite a property Default is readwrite Collections are declared using the declcollection tag It contains a list of task tags with IDs which specified already declared tasks Task has to be declared before it can be used in the collection As for the task collection has an optional requirement element which is used to specify the requirement for the collection If the requirement defined for both task and collection than collection requirement has higher priority and is used for deployment The main tag declares the topology itself In the example our main block consists of one task task one collection collection1 and two groups group and group2 A group is declared
17. n Number Scheme DDS version has a form of MAJOR MINOR PATCH where MAJOR the major number is increased when there are significant jumps in functionality MINOR the minor number is incremented when only minor features or significant fixes have been added PATCH represents a number of commits patches to a current major minor pair ii The DDS s version scheme reflects the fact that DDS is both a production system and a research project DDS uses odd minor version numbers to denote development releases and even minor version numbers to denote stable releases 4 Installation DDS supports Private and Shared installations A Private Installation it is when a user installs DDS for individual usage in his her local folder Any Private Installation can be used by other users as well It s just a matter of file privileges A Shared Installation 1t is when a site administrator installs DDS in some central location so it can be shared by many users This type of installation may be convenient for some users since they don t need to install DDS by their own In case of a shared Installation you need to execute one additional step see Section 4 5 Step 5 DDS shared Installation All the rest is the same as with Private Installations Be advised that in both cases DDS acts identically and always provides private clusters one for each user In case of a shared installation users share only binaries and configurations
18. ollection gt group id groupl n S nofGroups gt lt task gt task1 lt task gt lt collection gt collectionl lt collection gt lt collection gt collection2 lt collection gt lt group gt lt group id group2 n 15 gt lt collection gt collectionl lt collection gt lt group gt lt main gt lt topology gt DDS allows to define variables which later can be used inside the topology file During the preprocessing all variable are replaced with their values Variables are defined using the var tag which has two attributes id and Topology value Inside the file variable can be used as follows variable name In the above example we define two variables appNameVar and nofGroups When a particular task or collection is multiplied sometimes it is necessary for the user to get the index of the task or collection instance This can be done in two different ways In the definition of the executable path one can use special tags taskIndex and collectionIndex to get the task and collection index respectivley Before the task execution these tags are replaced with real values The second possibility is to get task and collection index from environment Two environment variables are defined for each task DDS TASK INDEX and DDS COLLECTION INDEX For each user task a set of environment variables is populated DDS TASK PATH full path to the user task for example main groupl collection_12 task_3 DDS G
19. onfiguration file r rms arg Defines a destination resource management system At the moment only the SSH plug in is supported therefore arg should be equal to ssh ssh rms cfg arg Specifies an SSH plug in resource definition file 25 Command line interface Name dds info can be used to query different kinds of information from DDS commander server UNIX Linux OSX Synopsis dds info h help v version commander pid status n agents number l 1 agents list Description The command can be used to query different kinds of information from DDS commander server Options commander pid Return the pid of the commander server status Query current status of DDS commander server n agents number Returns a number of online agents Iy agents list Show detailed info about all online agents 26 Command line interface Name dds test allows to test the running system UNIX Linux OSX Synopsis dds test t transport Description This command allows test the system after run Options t transport Performs transport test 27 Command line interface Name dds topology topology related commands UNIX Linux OSX Synopsis dds topology h help l v version l V verbosel set arg l disable validation l activate l stop l validate arg Description This command allows to perform topology related tasks O
20. pported Table 11 1 DDS s SSH plug in configuration fields 1 2 3 4 5 id must be any a host name with additional SSH a remote working RESERVED unique string or without a params could be directory login in a form empty This id string Jogin host fqdn is used just to distinguish different DDS workers in the plug in Example 11 1 An example of an SSH plug in configuration file rl anar lxg0527 gsi de p24 tmp test 0 this is a comment r2 user 1xi001 gsi de home user dds 0 125 user2 host tmp test 30
21. ptions h help Shows usage options v version Shows version information V verbos Causes the command to verbose additional information and error messages set arg Sets the given topology for the currently running DDS session disable validation Switches off topology validation activate Requests DDS to activate agents i e distribute and start user tasks stop Requests DDS to stop execution of user tasks Stop the active topology validate arg Validates topology file against DDS s XSD schema 28 Command line interface Name dds agent cmd send commands to agent UNIX Linux OSX Synopsis dds agent cmd h help l v version l command command arg getlog arg a all update key arg key arg l value arg Description This command allows to send commands to DDS agents Options getlog arg Download log files from all active workers a all Download all log files update key arg TODO KEY TODO value TODO 29 11 SSH plug in 11 1 Resource definition DDS s SSH plug in is capable to deploy DDS agents on any resource machine available for password less access public key ssh agent etc To define resources for the SSH plug in we use a comma separated values CSV configuration file Fields are normally separated by commas If you want to put a comma in a field you need to put quotes around it Also 3 escape sequences are su
22. quest the status information It will show process id of the DDS commander server daemon and the TCP port it listens on 22 Command line interface Name dds commander manages DDS facility UNIX Linux OSX Synopsis dds commander h help l v version start stop Description Qo Warning The command must not be used directly Please use the dds server command instead 23 Command line interface Name dds user defaults get and set global DDS options UNIX Linux OSX Synopsis dds user defaults h helpl l v version l V verbose l p path l d default c config argl f force key arg l wrkpkg l wrkscript l rms sandbox dir l user env script l server info file Description The dds user defaults command can be used to get and set global DDS options It also can be used to get different static settings related to the current deployment Options h help Shows usage options v version Shows version information M verbos Causes the command to verbose additional information and error messages P path Shows default DDS user defaults config file path d default Generates a default DDS configuration file f force If the destination file exists removes it and creates a new file without prompting for confirmation Can only be used with the d default options c config arg This options can be used together with other
23. server command to start stop status DDS servers dds server start 7 3 Deploy Agents In order to deploy agents you can use different DDS plug ins 7 3 1 Deploy Agents using SSH plug in DDS s SSH plug in is the best and the fastest way to deploy DDS agents When you don t have an RMS or you want to use a Cloud based system or even if you want just to use resources around you like computers of your colleagues then the plug in is the best way to go First of all you need to define resources Then use dds submit to deploy DDS agents on the given resources dds submit rms ssh ssh rms cfg FULL PATH TO YOUR SSHPLUGIN RESOURCE FILE 7 4 Check availability of Agents Using dds info you can query different kinds of information from DDS For example you can check how many agents are already online dds info n or query more detailed info about agents dds info 1 7 5 Set Topology To assign a topology to your deployment use How to Start dds topology set FULL PATH TO YOUR TOPOLOGY FILE 7 6 Activate Agents Once you get enough online agents you can activate them Activation of agents means that DDS will use the given topology to distribute user tasks across available resources agents dds topology activate DDS will automatically check whether available resources are actually sufficient to execute the given topology 18 8 How to Test XXXX 8 1 First Section XXXX 9 Tutorials
24. uped into collections and groups Both collections and groups can be used to group several tasks The main difference between collections and groups is that a collection requests from DDS to execute its tasks on the same physical machine if resource allow that This is useful if tasks suppose to communicate a lot or they want to access the same shared memory A set of tasks and task collections can be also grouped into task groups Another difference between groups and collection is that only groups can define multiplication factor for all its child elements Main group defines the entry point for task execution Only main group can contain other groups 6 1 Topology file At the moment we use an XML based file to store topologies XML is chosen because it can be validated against XSD schema DDS s XSD schema file can be found in DDS_LOCATION share topology xsd lt topology id myTopology gt Definition of tasks properties and collections lt main name main gt Definition of the topology itself where also groups can be defined lt main gt lt topology gt The file is basically divided on two parts declaration and main part All properties tasks and collections should be defined in the declaration part of the file Users can define any number of topology entities in that block even some which are not going to be used in the main block In the main block the topology itself is defined Groups and multiplicat
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