Revision as of 18:01, 1 December 2015

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.

• Checklist for new users

Getting support

• Please consider signing up to the gridpp dirac users mailing list: Sign up !
• For operational issues 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 something isn't working, 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

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.
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 http://lhcbproject.web.cern.ch/lhcbproject/dist/Dirac_project/dirac-install
chmod u+x dirac-install
./dirac-install -r v6r14p5 -i 27 -g 2015-09-03
.  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.

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

Back to GridPP Dirac overview page.