Revision as of 11:05, 25 September 2017

These instruction are for the dirac server at https://dirac.gridpp.ac.uk/DIRAC.

Introduction

This document describes how to quickly set up a simple Dirac UI client, create a job script and then submit it to a Dirac server for execution. You need to have a valid grid certificate and be a member of a supported VO. You do not need root access to the machine you are installing the Dirac UI on.

Note: new users may wish to start with the GridP UserGuide, which includes complete instructions for getting setup with GridPP DIRAC.

Getting support

• Please consider signing up to the gridpp dirac users mailing list: Sign up ! (It's fairly low traffic.) If you are using a non-institutional email, please let us know, it's hard to seperate the spam from the real requests. Thank you.
• If something isn't working, please try the mailing list first. It may help to include the output from your commands using the debug flag, which can be done with the -ddd flag, e.g.: dirac-proxy-init -ddd -g gridpp_user -M
• For operational issues ("Dirac server has died") please consider filing a GGUS ticket. If you set "Notify site" to UKI-LT2-IC-HEP, we'll see it quicker. If you don't know if your issue is operational, just use the mailing list :-)
• If your jobs don't run at a specific site that you think they should be running at (but run on other sites), please email lcg-site-admin at imperial.ac.uk. Please include your DN and VO. We will then check if it is a configuration issue on the dirac side and either fix it, or advise you whom to contact instead. Alternatively you can use GGUS for this issue. Please set "Notify site" to UKI-LT2-IC-HEP, we will reroute it to the appropriate site, if applicable.

Server URL

The Dirac server is installed at Imperial College. The Web interface is at:

 https://dirac.gridpp.ac.uk

You need a certificate installed in your browser.
To check that you are correctly registered with this dirac instance and that you are a member of a dirac supported VO, visit [the server] and check the bottom righthand corner. If this shows you as "visitor" and you cannot change this, you are not registered. In this case, please contact lcg-site-admin@imperial.ac.uk

Dirac client installation

You need an SL6 machine, with your user cert and key located in the $HOME/.globus directory. You also need to be a member of a dirac supported VO.

Note: the installation does not work on SL5 or SL7. Please use an SL6 machine. If your cluster does not support SL6, you may wish to consider using a GridPP CernVM.

You can try and run this python script (chmod u+x install_dirac_ui.py, ./install_dirac_ui.py): dirac ui install script.

Or you can run the command sequence by hand in a bash shell:

mkdir dirac_ui
cd dirac_ui
wget -np -O dirac-install https://raw.githubusercontent.com/DIRACGrid/DIRAC/integration/Core/scripts/dirac-install.py
chmod u+x dirac-install
./dirac-install -r v6r17p28 -i 27 -g 2017-01-27 
.  bashrc 
dirac-proxy-init -x # (needs user cert password)
dirac-configure -F -S GridPP -C dips://dirac01.grid.hep.ph.ic.ac.uk:9135/Configuration/Server -I
dirac-proxy-init -g [your_vo_goes_here]_user -M # (e.g. dirac-proxy-init -g comet.j-parc.jp_user -M)

If you see an error like below then you probably are not registered with the dirac instance. Usually you are automatically registered, but there is a delay of several hours between registering with the VO and the dirac server picking this up. If after 24h you still get the same error message, please send an email to lcg-site-admin -at- imperial.ac.uk and we'll have a look.

Could not sync dir Cannot get URL for Framework/BundleDelivery in setup MyDIRAC-Production: Option /DIRAC/Setups/MyDIRAC-Production/Framework is not defined

A note on CA certificates

When you install the dirac UI, the script will automatically download a current copy of these certs for you and store them in [dirac_ui_dir]/etc/grid-security/certificates. This will be sufficient for a couple of weeks of testing. If you are planning on using your dirac UI for longer, you need to update these certificates regularly. Most grid sites maintain a current copy of these files somewhere on their systems and you should link to those (try /etc/grid-security/certificates or at Imperial /vols/grid/certificates -- if in doubt ask your friendly sys admin :-) instead.

If there is no regularly maintained set of CAs available, run the following command periodically:

source bashrc; dirac-admin-get-CAs 

It is convenient to this this once per day using a cron job.

Submitting a 'Hello World' job via dirac

Create a proxy

If you don't already have a valid proxy you should create one:

.  bashrc 
dirac-proxy-init -g [your_vo_goes_here]_user -M (e.g. dirac-proxy-init -g comet.j-parc.jp_user -M)

Create a JDL

Now we are ready to create a simple Dirac jdl. Put the lines below into a file Simple.jdl:

[
JobName = "Simple_Job";
Executable = "/bin/ls";
Arguments = "-ltr";
StdOutput = "StdOut";
StdError = "StdErr";
OutputSandbox = {"StdOut","StdErr"};
]

Submit a job

$ dirac-wms-job-submit -f logfile Simple.jdl 
JobID = 236

Check job status:

$ dirac-wms-job-status -f logfile

JobID=236 Status=Waiting; MinorStatus=Pilot Agent Submission; Site=ANY 

and eventually:

$ dirac-wms-job-status -f logfile 
JobID=236 Status=Done; MinorStatus=Execution Complete; Site=LCG.Glasgow.uk;

The jobs can also be monitored using the Web interface. Go to Jobs ->Job monitor You can also submit a job using the Web interface (Tools->Job Launchpad).

Once the job is done, retrieve the output:

$ dirac-wms-job-get-output -f logfile

Advanced job management

Using the DIRAC API to submit a Job

An example of a hello world job can be found here.
The corresponding section in the DIRAC user guide can be found here.

Selecting a site platform

By default GridPP DIRAC will only run jobs at sites providing an EL6 based operating system. If you would like to submit a job that requires a different operating system (such as EL7) this can be set using the Platform option in the JDL:

Platform = "EL7";

If is also possible to specify AnyPlatform as the platform name to disable this check:

Platform = "AnyPlatform";

Note that all parts of this JDL string are case sensitive (the word Platform and the platform string itself).

Users of the DIRAC API can use the job.setPlatform("EL7") function to configure this behaviour.

Ganga users can set extra options, including the platform, via the backend settings attribute:

j = Job(backend=Dirac())
j.backend.settings['Platform'] = "EL6"

Basic data management

(using the UI and proxy you just setup)
List files in the dirac file catalogue (please do not use the file catalogue for anything else):

$ dirac-dms-filecatalog-cli
Starting FileCatalog client
File Catalog Client $Revision: 1.17 $Date: 
FC:/> ls
(use 'exit' to, well, exit)

Add a file to an SE (here UKI-LT2-IC-HEP-disk). Please replace /gridpp with the name of the VO you are using, and firstname.lastname with your first and last name (or alias or superhero, it just has to be unique):

dirac-dms-add-file /gridpp/user/f/firstname.lastname/myfile.txt myfile.txt UKI-LT2-IC-HEP-disk

List all replicas:

dirac-dms-lfn-replicas /gridpp/user/f/firstname.lastname/myfile.txt

Copy file from SE to disk:

dirac-dms-get-file /gridpp/user/f/firstname.lastname/myfile.txt

Replicate file from on SE to another (file is currently at UKI-LT2-IC-HEP-disk):

dirac-dms-replicate-lfn /gridpp/user/f/firstname.lastname/myfile.txt UKI-LT2-QMUL2-disk

Ask for the access URL (you should only need this for very special cases):

dirac-dms-lfn-accessURL  /gridpp/user/f/firstname.lastname/myfile.txt UKI-LT2-IC-HEP-disk

Remove file from a specific SE:

dirac-dms-remove-replicas /gridpp/user/f/firstname.lastname/myfile.txt UKI-LT2-IC-HEP-disk

Remove all replicas (?):

dirac-dms-remove-files  /gridpp/user/f/firstname.lastname/myfile.txt

Using the asynchronous files transfer tools.
Replicate a file to a given SE:

dirac-dms-replicate-and-register-request [make up an id for this transfer] [LFN] [target SE]

e.g. replicate a file to the RHUL SE (files must exist and be registered in the file catalogue):

dirac-dms-replicate-and-register-request daniela1 /gridpp/user/d/daniela.bauer/small.text.file.txt UKI-LT2-RHUL-disk

Querying the transfers:

dirac-rms-show-request [transfer if from above, e.g. daniela1]
dirac-rms-show-request --Status='Done' --Since='2016-05-05'

dirac command reference

No guarantees....

Back to GridPP Dirac overview page.