In the coming weeks several significant changes will be applied to the LHCb Computing environment, as a result of the software improvement efforts and the evolution of the infrastructure.

Configuration and build management changes

As from the latest releases, the configuration files for the CMT configuration management tool is not available for the LHC Computing Grid (LCG) software stacks, and has been replaced by CMake. This means that the new tools (lb-dev and lb-run) are mandatory to configure and run the new versions of the software, and that SetupProject does not work with these versions (all applications using Gaudi v28r0 or later, e.g. DaVinci v42r0 or posterior). You can find more information regarding those tools at the following URL:

https://twiki.cern.ch/twiki/bin/view/LHCb/SoftwareEnvTools

These change forced us to rethink our environment scripts. This means that, as from the v9 branch of LbScripts (scheduled for release next week) the already deprecated aliases like "SetupDavinci", "SetupBender", "SetupMoore"... will not be present any more and should be replaced by the appropriate call of lb-run.

Please note that lb-run can be used with all versions of our applications, even those pre-dating the move to CMake as it reverts to the old configuration tool.

You can already try the new version of the scripts by creating a file called ".devLHCBLoginscript" in your home directory on lxplus, as specified in the LbScripts documentation (http://lhcb-release-area.web.cern.ch/LHCb-release-area/DOC/lbscripts/)

Management of local installations of the LHCb Software

This change also means that the "install_project" tool allowing local installation has been deprecated and that its successor "lbinstall" should now be used for local installations of the LHCb Software, c.f.

https://gitlab.cern.ch/lhcb-core/lbinstall

We however recommend the use of CVMFS (http://cernvm.web.cern.ch/portal/filesystem) as this allows using the software versions and conditions used by Grid jobs.

Changes in the default software configuration

The default compiler for the centos7 platform is now the GNU compiler version 6.2 instead of 4.9 as was done previously. The default for SLC6 stays GCC 4.9 for the moment, but will be upgraded to GCC 6.2 as soon as all applications and tools are ready.

AFS Phase-out

Finally, as already mentioned during the computing workshops, CERN IT have decided to phase out the Andrew File System (AFS) cell at CERN, as from 2019. For more details:

https://twiki.cern.ch/twiki/bin/view/IT/AfsPhaseout

To progress on this migration, we will change the default environment on lxplus to CVMFS, in the first week of May.

You can already use CVMFS by default by creating a file called “.devLHCBuseCVMFS” in your home directory on lxplus as specified in:

http://lhcb-release-area.web.cern.ch/LHCb-release-area/DOC/lbscripts/

Don't hesitate to contact the Core Software team in case of problems or questions,

-- BenjaminCouturier - 2017-01-25

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Topic revision: r2 - 2017-04-26 - BenjaminCouturier
 
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