Farm Upgrade to Alma9

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Farm Upgrade to AlmaLinux 9

The Jefferson Lab computing farm is being upgraded from CentOS 7 to AlmaLinux 9 in the coming months. This document outlines changes to the environment for all users of the interactive login nodes (ifarm), SLURM, and SWIF.

Farm Upgrade Schedule and Worker Node Selection

The farm is being upgraded in a series of steps. Between now and June, the farm composition will change from majority CentOS 7 to predominantly AlmaLinux 9. At the time of this writing, CentOS 7 is the default. This default will change at a later step in the conversion process. Users may currently select which nodes run their jobs using Slurm features/constraints. This article provides details on feature-based node selection. SWIF can pass features through to Slurm. See the SWIF introduction and SWIF command line reference for details.

The interactive (ifarm) nodes currently run CentOS 7. A new machine, ifarm9.jlab.org is available for AlmaLinux 9 use now. Two new ifarm machines that will run AlmaLinux 9 are on order. They will replace the existing ifarm machines and include more per-core memory and temporary disk space.

Software Environment and Filesystem Changes

The use of /apps is deprecated and is not available on farm AlmaLinux 9 machines. CVMFS is now used to distribute software. It is rooted under OASIS and can be used with modulefiles as before. For questions about software package availability, please submit a ServiceNow incident. For hall-specific software distribution questions, contact your computing coordinator.

The legacy /site area has been removed. The path to Jasmine (tape) and cache tools will change from /site/bin to /usr/local/bin. The CUE /u/scratch area has also been removed.

Remote Access for Visual Studio Code and SSH

If you use Visual Studio Code for development and connect it to the ifarm hosts using the Remote-SSH extension, you may be aware that the current version has dropped support for CentOS 7 remote ends. Since AlmaLinux 9 has the newer system software required, you can use ifarm9 as the remote host instead. This guide to using SSH with the farm includes VS Code details at the end.