Deployment of the CMS software on the WLCG Grid

The CMS Experiment is taking high energy collision data at CERN. The computing infrastructure used to analyse the data is distributed round the world in a tiered structure. In order to use the 7 Tier-1 sites, the 50 Tier-2 sites and a still growing number of about 30 Tier-3 sites, the CMS software has to be available at those sites. Except for a very few sites the deployment and the removal of CMS software is managed centrally. Since the deployment team has no local accounts at the remote sites all installation jobs have to be sent via Grid jobs. Via a VOMS role the job has a high priority in the batch system and gains write privileges to the software area. Due to the lack of interactive access the installation jobs must be very robust against possible failures, in order not to leave a broken software installation. The CMS software is packaged in RPMs that are installed in the software area independent of the host OS. The apt-get tool is used to resolve package dependencies. This paper reports about the recent deployment experiences and the achieved performance.