CentOS 7 Upgrade

Starting in the summer of 2017, ACCRE staff will begin upgrading the cluster operating system from CentOS 6 to CentOS 7. Compute nodes and gateways will be gradually upgraded over the course of 2-3 months as users and groups transition to the new environment. ACCRE is aiming to complete the process by October of 2017.

What will be potentially difficult?

The first thing researchers ask about is their data. Rest assured that all your data in /home, /scratch, and /data will be available from the new environment!

However, any software that was built in CentOS 6 will most likely need to be rebuilt (i.e. compiled and linked together into an executable program). This includes packages that were available through the pkginfo and setpkgs commands. ACCRE staff will be making rebuilt software available through a new tool called Lmod. Software that has been built and is maintained by individual users (e.g. in /home) or groups (e.g. in /scratch or /data) will need to be rebuilt by the users or groups. ACCRE staff will be available to assist. Tools that rely on older versions of system libraries may be good candidates for running inside of Singularity containers.

Groups with access to custom gateway servers will need to schedule a full-day downtime with ACCRE to provide adequate time for their gateway to be upgraded to CentOS 7. This downtime can be scheduled any time between July 5 and October 1. We will be reaching out to custom gateway groups prior to June 1 to schedule these downtimes. Note that software built locally on a custom gateway will most likely need to be rebuilt. ACCRE staff will be available to assist if needed.

What will be new?

Some changes are more difficult to make in production than others, so ACCRE will be taking this opportunity to roll out a handful of new services meant to enhance the security and usability of the cluster environment. These are not new features added to CentOS 7, but deploying them in a new environment should be less disruptive overall:

  • ACCRE is exploring transitioning to a new method of authentication that would use Vanderbilt’s ePasswords. This would get ACCRE out of the business of managing passwords, with the exception of a few special projects.
  • Lmod is a tool that better manages dependencies between hand-built software packages to avoid many common compiler and dependency errors. This tool will be available in parallel with setpkgs and pkginfo starting in Spring 2017, and then will be the standalone package manager in the CentOS 7 environment. We will begin providing documentation and training for this exciting new tool during Spring 2017.


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