User manual
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1. commands sequence which send UDP packets from the selected sender to all other overlay members gt create_experiment 60 gt slow_start_experiment 5 gt wait_until_stable gt set_value 0 BWTest0 Measurement 0 BlocksXBlockSizeXRate 1024x1024x1000 gt get_performance Here command get_performance which collects the time that all receivers received the last packet is not included in Hypercast2 0 released version Commend set_value 0 BWTest 0 Measurement 0 BlocksXBlockSizeXRate 1024x 1024x1000 is also a updated command which sends UDP packets from the sender at the specified rate it is 1M in this example In hypercast2 0 standard version the sender in the command set_value sends UDP packets to the network as soon as possible In wide range network environment like Internet it doesn t work well usually the loss ratio of UDP packets for all receivers is very high that makes the statistics on the delay measurement useless 102. Toolkit for Doing Wide area Experiment on PlanetLab Testbed User Manual MNG Group March 31 2003 1 Introduction PlanetLab is a project initialized by tens of universities mainly are universities in USA and Europe to build a wide area testbed which provides the capacity of doing experiments in a real distributed environment Currently there are totally about 100 sites and more than two hundred PlanetLab machines each of them is a Dell PC running LinuxRedHat kernel version 2 4 19 The details information about PlanetLab can be found at the following websites http www planet lab org http ccwp7 in2p3 fr mapcenter planetlab SSH is the only way to access to PlanetLab hosts that implies you would be asked to type password or passphrase in our case it is passphrase We cannot update the configurations like etc hosts equiv etc hosts allow and so on to make all PlanetLab machines are friendly or equivalent to each other that provides the way to access from one PlanetLab machines to another without typing password To solve this problem we implemented a toolkit that consists of a set of Expect scripts Expect is a kind of script language t hat works on top of TCL The main advantage of Expect is that it can automatically finish the process of interaction when people log into a remote machine using SSH To learn Expect language please refer to the book Exploring Expect This manual presents a brief description
3. account and accept authentication from your local administrator The following steps are needed to set up your account e Register on the PlanetLab testbed Go to PlanenLab homepage click Users which is at the left side of the page On the displayed page click new account and follow the instruction to fill the registration form Click register and finish the registration Don t forget the passphrass you typed while generating your private public key pair Note The following command is used to create a public private key pair ssh keygen t rsa f ssh identity It will ask you to type a passphrase DON T FORGET IT The output is two files identity and identity pub Be careful when you create a private public key pair because the key generate command will overwrite the key files in the directory HOME DIRECTORY ssh here HOME DIRECTORY is the home directory when you login to a local machine using your account Note Make sure the public key file consists of a single line On some operating systems e g Windows Solaris the ssh keygen program generates public keys that contain newlines and causes a problem We recommend you to create the public private key pair on a Linux host e Enable your account Send e mail to local administrator including the account name and E mail address to tell that your PlanetLab account has been created and needs to be enabled The local administrator will enable your account and assign a login
4. amics of Internet Before starting your experiment you need to test PlanetLab hosts using ssh_test_alive or ssh_test_alive_unify command and make sure the hosts you used are alive A failed host should be commented by inserting at the beginning of the line e When you want to run your program on remote PlanetLab hosts you need to prepare the working environment first including installing needed software such as JAVA and setting PATH environment variable on remote hosts When multiple persons share a login name each one should create and work in his or her own working directory Now you are ready to use the PlanetLab toolkit 3 Scripts for Running Experiments on PlanetLab Hosts In this section we describe the functions of the scripts commands in the toolkit Except the script ssh_login all other scripts in the toolkit are working with a text file in which multiple PlanetLab hosts are listed randomly or in the order depending on the requirement of your experiment The host list file for example hostslist file looks like 128 111 52 61 150 135 65 2 128 2 198 199 129 237 123 250 150 135 65 3 128 95 219 192 Blank lines and the comment lines begin with will be ignored by all scripts 1 ssh_login Usage ssh_login hostname This command automatically logins in remote host hostname without typing passphrase ssh_login_batch Usage ssh login_batch hostlist file When typing command ssh_login_batch
5. and_runServerTv bash_profile cd streaming_xa serverProxy xa_tv run sh e command_runServerUnt bash_profile cd streaming_xa serverProxy xa_untouchable run sh You can create your own command file in the same way Creating command files can save a lot of time and avoid unnecessary typing errors Note The commands in a command file should be written in a single line separated with semi colon signs 6 2 An Example of Experiment Step 1 Setup DT server Execute the following command on a local machine where DT server is running java classpath hypercast2 0 jar edu virginia cs mng hypercast DT DT_ Server 8081 Step 2 Start RunControl Execute the following command on a local machine where RunControl is running java classpath hypercast2 0 jar parser jar jaxp jar edu virginia cs mng hypercast DT DT_RC2 noserver 1500 where 1500 is the port number for connecting RunServers Step 3 Start RunServers Execute the following script on a local machine for example iodine cs virginia edu ssh_command_unify hostslist file 0 20 command_RunServer The contents of the file command_RunServer look like source bash_profile cd widearea test java classpath hypercast2 0 Jjar parser jar jaxp jar edu virginia cs mng hypercast testing_and_monitoring RS2 128 143 71 28 1500 1 Step 4 Type RunControl commands and finish experiment When RunControl starts it provides a UI for users to type commands The following is an example of
6. for installing and using the toolkit The establishment of the related experiment environment is discussed too 2 Getting Started 2 1 Supported Platforms The current toolkit implementation is designed to work on a Linux PC in which Expect is integrated as a part of standard distribution This toolkit has been tested on RedHat 7 1 kernel 2 4 2 2 RedHat 7 3 kernel 2 4 18 3 and RedHat 8 0 kernel 2 4 18 2 2 Set Up Your PlanetLab Account and Password Passphrase Before starting work on PlanetLab testbed you need to build an account and set up password pass phrase This password passphrase is stored in a private public key pair You need to upload your public key when creating the account and keep your private key on your local host According to the policy of PlanetLab there are ten login accounts like uv1 uv2 uv10 managed at each PlanetLab site The administrator at the local site will assign a login name such as uv1 to your account After the authentication your public key will be distributed over all PlanetLab hosts and you can use the assigned login name and your private key with your password passphrase to login to any PlanetLab host or start a remote job on a remote PlanetLab host The PlanetLab toolkit serves to automate the interaction with all PlanetLab hosts The following steps shows the procedure to establish a PlanetLab account Set up your account Before accessing PlanetLab hosts you should establish your
7. hostlist file you first automatically login into the machine listed as the first one in the file hostlist file Type exit under the shell prompt will exit the current connected machine and automatically login in the next machine The process will continue until all machines have been accessed scp_command Usage scp command hostlist file sentfile file The file hostlist file is specified in the same way as command ssh_login_bat ch Sentfile file is the full name of the local file you want to copy to remote machines In the above script for each remote host the local file sentfile file will be copied to the remote directory REMOTE_HOME_DIR Working_directory that is defined in the configuration file planetLab conf The time limit on executing the scp command for each remote host is 1800 seconds 30 minutes It is enough to finish most scp commands An example of scp_command is shown as below scp_command hostlist file home hypercast hypercast prop scp_fromremote Usage scp_fromremote hostlist file remote file name local dir This script copies a file from remote machines specified in the file hostlist file to local directory local dir It is very useful for collecting data files from multiple remote machines for example typing scp_fromremote hostlist file udp txt home hypercast test will copy files udp txt from remote directory REMOTE_HOME_DIR Working_directory to local directory home hypercast test ssh_comma
8. ments The interaction processes of accessing different remote hosts using SSH are similar with the minor difference For example When running a SSH command to access a PlanetLab host you are asked for a passphrase Specifically the following message is displayed on the screen Enter passphrase for key home hypercast ssh identity The scripts in the toolkit are customized to satisfy this requirement But other operation systems might ask for a password The message displayed on the screen looks like hypercast iodine s password To adapt to the new requirements of the different system you only need to make a minor update in the scripts In each scripts replace the following line expect re Enter passphrase for key with expect re password 6 Doing Experiments on PlanetLab Machines 6 1 Create Command Files For the script ssh_command and its variants the command s that will be executed on remote hosts can be stored in a text file called command file This is useful when the remote commands are too long and complex to type each time In this toolkit several command files have been created e command_killJava killall 9 java e command_RunServer source bash_profile cd widearea test java classpath hypercast2 0 jar parser jar jaxp jar edu virginia cs mng hypercast testing_and_monitoring RS2 128 143 71 37 1500 1 e command_runClientProxy source bash_profile cd streaming_xa clientProxy xa runp sh e comm
9. name for example uv3 to your account It usually takes one or two hours for the login name to become available for you to use after your PlanetLab account is enabled Send e mail to local administrator including your name and E mail address you typed in the registration form to tell that your PlanetLab account has been created and needs to be enabled The local administrator will enable your account and assign a login name for example uv3 to your account and inform you through e mail It usually takes one or two hours for the lo gin name to become available for you to use after your PlanetLab account is enabled Ensure your private key is stored in the right place Make sure that your private key it is the file identity in the local directory HOME DIRECTORY ssh It is usually done by the key generate command 2 3 Downloading and installing PlanetLab Toolkit Go to the PlanetLab toolkit website http www cs virginia edu mn group software PlanetLab_toolkit and download planetLabtools tar gz Save the downloaded package into a directory DIR execute the following command cd DIR tar zxvf planetLabtools tar gz A sudirectory named planetLabtools will be created under the directory DIR The directory DIR planetLabtools is your working directory 2 4 Prepare working environment Configure the settings in the configuration file planetLab conf cd DIR planetLabtools vi planetLab conf The contents of the file plane
10. nd Usage ssh command hostlist file command file command The file hostlist file is as before the command which will be executed on all remote machines speficied in the file hostlist file can be stored in the file command file or specified directly in the command line Here are two examples Example 1 ssh_command hostlist file rm widearea test udp txt It will remove all files matching udp txt under the remote directory REMOTE_HOME_DIR widearea test Example 2 ssh_command hostlist file command file the contents of the file command file are source bash_profile cd widearea test java classpath UnicastTest jar udp_r 2000 It will start JAVA program udp_ron all specified remote hosts Note In most experiments we need to run non interactive tasks on remote machines there are some tricks to do that with Expect scripts The above script is a way to run remote non interactive jobs please check the contents of the script it works But it may not be the best way If you find some better ways please let me know Note If you prefer to observe the output of the command on each remote host you need to edit the script ssh_command by replacing the following line expect re puts nfinished n with line expect eof ssh_test_alive Usage ssh test_alive hostlist file The script ssh_test_alive is used to test whether the machines specified in hostlist list are alive or dead Note that the command we use
11. nly work on the set of hosts defined in the file hostlist file that starts at the host with index start_index and includes num_of_hosts hosts 4 Customize the Scripts in the Toolkit for Specific Objectives The scripts in the toolkit usually execute the same action on each remote host Sometimes this behavior doesn t satisfy our requirement For example on each remote host we create a file buddylist to cache the logical coordinates of the remote host When you want to copy the buddylist file on a set of remote hosts to a local directory the scripts described in the section 3 cannot correctly finish this job It is easy to update standard scripts to do this specific work The only thing needs to be done is to edit the script scp_fromremote or scp_fromremote_unify by replacing the following line spawn scp UserID host home UserID WorkingDirectory sentfile dir with spawn scp UserID host home UserID WorkingDirectory sentfile dir host coord We give the updated script a new name scp_buddylist_fromremote or scp_buddylist_fromremote_unify We typing the following command scp_buddylist_fromremote hostlist file buddylist home hypercast test For each remote host assume its IP address is REMOTE_IP specified in the file hostlist file it will copy the buddylist file from the remote directory REMOTE_HOME_DIR Working_directory to the local directory home hypercast test and store it in the file REMOTEIP coord In
12. tLab conf look like UserlD my_login Passphrase my_passphrase Working_directory my_working_dir You need to replace my_login with your actually login name for example uv3 and replace my_passphrase with the passphrase you typed when creating private public key pair For security reason we recommend you to type in your passpgrase in the file planetLab conf before starting your experiments and delete it from the file planetLab conf when the experiments are finished The Working_directory is used for all commands with prefix scp When specifying my_working_dir as the working directory the actual remote directory is REMOTE_HOME_DIR my_working_dir For example if set Working_directory widearea test then the command scp_command_unify host list txt 0 10 home hypercast tmp test txt will copy the local file home hypercast tmp test txt to the directory REMOTE_HOME_DIR widearea test on the remote hosts specified by host list 0 10 explained in the User Manual e Prepare host list file Most PlanetLab toolkit scripts work with a host list file which is a list of current active PlanetLab machines Any line beginning with is comment line A sample host list file host total txt is provided with PlanetLab toolkit package The full list of PlanetLab hosts can be found at https www planet lab org db nodes nodelists php Note The status of PlanetLab testbed is not very stable due to the dyn
13. this toolkit we create a few of customized scripts for specific goals You can create your own customized scripts in the same way 12 scp_buddylist_fromremote Usage scp_buddylist_fromremote hostlist file remote file name local dir 13 scp_buddylist_fromremote_unify Usage scp_buddylist_fromremote_unify hostlist file start_index num_of_hosts remote file name local dir The meaning of the scripts scp_buddylist_fromremote and scp_buddylist_fromremote are explained above 14 scp_buddylist_toremo te Usage scp_buddylist_toremote hostlist file remote file name local dir 15 scp_buddylist_toremote_unify Usage scp_buddylist_toremote_unify hostlist file start_index num_of_hosts remote file name local dir For a host assume its IP address is REMOTE_IP defined by hostlist file or hostlist file start_index num_of_hosts either of the above two scripts copies the file local dir REMOTE_IP coord to the remote file REMOTE _HOME_DIR Working_directory buddylist There are multiple other customized scripts in the toolkit including ssh_coord_first ssh_coord_first_unify ssh_coord_follow ssh_coord_follow_unify ssh_ttcp_tcp ssh_ttcp_tcp_unify ssh_ttcp_udp and ssh_ttcp_udp_unify They are created by the similar method mentioned above If interested you can take a look of the script to understand what these scripts do It is an easy job 5 Extend the PlanetLab Toolkit for working in Other SSH oriented Environ
14. to test a remote machine runs a non interactive task on remote machine which will not display any message on local screen to show the results In this case the only way to find a down machine is timeout of the command which implies we don t get any response from the tested remote machine Note If the script ssh_test_alive tells a host is down this host may notbe really down This host may be alive but just responses after a long time You can try script ssh_login to detect whether this host is really down On the other hand if the script ssh_test_alive says a host is alive this host is certainly alive The above scripts will execute identical commands on all hosts specified in the file hostlist file To provide a flexible way to only execute commands on a selected set of hosts we define the following set of variants of abo ve scripts 7 ssh_login_batch_unify Usage ssh_login_batch_unify hostlist file start_index num_of_hosts scp_command_unify Usage scp_command_unify hostlist file start_index num_of_hosts sentfile file scp_fromremote_unify Usage scp_fromremote_unify hostlist file start_index num_of_hosts remote file name local dir 10 ssh_command_unify Usage ssh_command_unify hostlist file start_index num_of_hosts command file command 11 ssh_test_alive_unify Usage ssh_test_alive_unify hostlist file start_index num_of_hosts The above derived set of scripts do the same work as their original versions but o
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