Vac commissioning procedure

This page outlines the administrative and technical steps needed to commission a Vac site for LHCb. The VacConfiguration page complements this and provides guidance to sites.

  • The site contacts a member of the ops team to request that the site be included in the configuration database.
  • The Vac site name is agreed. This should be of the form VAC.Example.cc (for place names, like Manchester) or VAC.EXAM.cc (for abbreviations, like CERN). Normally this should be adapted from their existing LCG.Example.cc or LCG.EXAM.cc site name. It is essential to double check the right name is used by the site as the software will allow them to pull jobs for other sites or their LCG site, potentially side stepping the Vac site's status in the production mask.
  • The site needs to supply the Vac space name, which will be within their DNS space. This need not be a live DNS entry or correspond to a real host. The Vac space name is used as a virtual CE name in DIRAC.
  • The site needs to supply the host certificate DN they will use to contact the matcher. Normally, this should be an LHCb specific name within their DNS space. So lhcb-vm.example.cc would be a sensible choice if they owned example.cc
The ops team member then makes these changes in the DIRAC configuration database, using the above information:

  • In /Resources/Sites/VAC/ copy one of the existing VAC site sections and rename it, replacing the site name, CE name, email address, and co-ordinates within it.
  • In /Operations/Defaults/JobScheduling/RunningLimit copy one of the existing VAC site sections and rename it. This should have JobType limits of 0 for User and DataStripping.
  • In /Registry/Hosts copy one of the existing VAC host sections and rename it. The new section name should follow the existing pattern, using the lowercase host name from the DN's CN as the section name. For example, lhcb-vm.example.cc . Inside the new section change the DN option to the host certificate DN provided by the site, in slash (/O=.../CN=...) rather than comma (CN=... , O=...) format.
  • Double check this all has been properly committed (eg by looking at the text view and searching for all the references to the site by name.)
The ops team member then submits some LHCb DIRAC Test jobs to the CE, so there are some jobs ready for the site to run when they are setting it up. This can be done with the command: dirac-lhcb-sam-submit --ce=vac.example.cc where vac.example.cc is the CE / Vac space name. Then they inform the site that the configuration has been done and test jobs submitted.

To check that the site is reliably running LHCb DIRAC Test tests, it is necessary to make sure that more than one Test job successfully runs on the same VM node. This establishes that the VMs are being recycled correctly, and not just running one Test job to the green Done state but then failing to shutdown and be recreated ready for another one. One way to do this is to submit more LHCb DIRAC Test jobs than there are VM slots in the Vac space. Once this check is done, the site is ready for putting into the production mask as with new LCG sites.

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Topic revision: r5 - 2014-12-09 - AndrewMcNab
 
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