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PSI Tier 3 User Documentation

Using containers to work with older CMSSW versions on RHEL9

Using containers to work with older CMSSW versions on RHEL9¶

You can use the wrappers offered by the cmssw-osenv project that are already installed in CVMFS. /cvmfs/cms.cern.ch/common/cmssw-env. You can add additional directories that are to be mounted into the container using the -B /work,/scratch syntax.

Interactively installing a CMSSW release¶

Start up a container suitable for the CMSSW release you want to install. In the following example we will use an EL7 (Enterprise Linux 7 compatible) container. Ensure that /work is mounted into the container

/cvmfs/cms.cern.ch/common/cmssw-env -B /work --cmsos el7

Now, inside of the containerized environment just proceed to install CMSSW in your /work/$USER directory as usual

cd /work/feichtinger/CMSSW
source ${VO_CMS_SW_DIR}/cmsset_default.sh
export SCRAM_ARCH=slc7_amd64_gcc700   # override needed for this particular CMSSW version
cmsrel CMSSW_10_6_37

Running slurm jobs in a containerized environment¶

An example job based on first creating a temporary payload file that then is passed for execution to the cmssw-env container command

#!/bin/bash
#SBATCH --job-name=cmssw-job
#SBATCH --partition=standard
#SBATCH --ntasks=1
#SBATCH --time=08:00:00

echo "# starting Job at $(date) on node ${HOSTNAME}"
echo "###########################"
echo "# INITIAL ENVIRONMENT START"
echo "###########################"
env    
echo "##########################"
echo "# INITIAL ENVIRONMENT END"
echo "##########################"

JOBSCRATCH=/scratch/${USER}/${SLURM_JOBID}
mkdir -p $JOBSCRATCH
payload=$(mktemp ${JOBSCRATCH}/apptainer-payload-XXXXXX.sh)

cat > "$payload" << EOF
# Adapt this based on your install directory
cd /work/feichtinger/CMSSW/CMSSW_10_6_37
source ${VO_CMS_SW_DIR}/cmsset_default.sh

#For this particular CMSSW version we need to override the ARCH
export SCRAM_ARCH=slc7_amd64_gcc700

cmsenv 

# IMPLEMENT YOUR FUNCTIONALITY HERE!

EOF    

chmod u+x "$payload"

# Launch the payload in the container, make sure that /scratch
# and /work are available inside of the container

/cvmfs/cms.cern.ch/common/cmssw-env --cmsos el7 -B /scratch,/work \
                                    --command-to-run $payload

rm -rf "$JOBSCRATCH"
echo "# ending Job at $(date) "

References¶