Dear ATLAS T1s and T2s,

we are starting to look at migrating to CentOS7. As said during the infrastructure plenary at the ATLAS S&C week we will not set deadlines to migrate until early 2019, but SL6 is becoming obsolete for a number of features we would like to progress with. The major ones are
We would like to move from Python 2.6 to python 2.7
We would like to start using singularity on CentOS7 sites in production at the end of the year
User spaces are better supported (in CentOS 7.6 user spaces will become production rather than technology preview)
Native CentOS7 releases are now being built and they will not run on SL6 nodes.
and to reduce the effort required to coordinate a mass migration next year we strongly encourage sites that can to start migrating to CentOS7 as soon as they think they can do it.

ATLAS software have been validated since almost two years and for over a year the WN middleware of all our three grids (OSG, nordugrid, EGI) has been ready. There are already >15 sites with CentOS7 queues in production for both production and analysis and some of them are already CentOS7 only sites.

Please refere to the CentOS7 readiness twiki for further information on some of the requirements (for example install singularity) and how to upgrade.

If you need any further information please contact atlas-adc-operations@NOSPAMcern.ch or me and Xin.

thanks

cheers
alessandra