What will happen?

During 2023 or possibly early 2024 NSC will upgrade the operating system of Sigma from CentOS 7 to Rocky Linux 9.

Other changes will be kept to a minimum. You will still use SSH or Thinlinc to log in, you will still submit your jobs to Slurm, etc.

Most applications provided by NSC will continue to work. Minor adjustments to job scripts might be needed. Some of these applications will run natively in the new operating system, some will have been recompiled, others will be run in a CentOS 7 container using Apptainer.

Regardless of which method has been used to get an application running in the new environment, we have not seen any significant performance impact during our testing. Some applications are even running faster than before.

If you have built or installed your own application you will need to choose a suitable way to move the application to the new environment. There are several ways to do this. Which one to use depends on the application. NSC Support can assist you with this. Documentation will also be available on this page later.

As you can read on the corresponding Tetralith page, Tetralith will also be upgraded.

Unlike Tetralith, Sigma has relatively few compute nodes (and very few fat and GPU nodes). This makes it more difficult to do the upgrade gradually as we will do on Tetralith. Instead we will likely upgrade all Sigma nodes during a short (a few hours) downtime.

The Sigma upgrade will happen at least a few weeks after the start of the Tetralith upgrade.

Users who want to test their jobs before the Sigma upgrade can do so on Tetralith. Many Sigma users already have access to Tetralith. Those that don't can get limited access (you will only be able to run test jobs) by contacting NSC Support.

If we find applications that the user and NSC cannot easily get working in the new environment, we have the the option to keep some CentOS 7 compute nodes online until 2024-06-30 for those applications. However, we will do our best to make sure this does not happen.

When will things happen?

Sigma will probably be upgraded a few weeks after the start of the Tetralith upgrade (i.e during November). We are still discussing some other options, e.g early 2024.

We will give at least two weeks notice before the upgrade.

Why are we doing this?

The current operating system CentOS 7 (which is based on RedHat Enterprise Linux 7) will not receive any security updates after 2024-06-30.

As Sigma is planned to continue operating at least until January 2025, we need to upgrade the operating system.

This is not the final version of this document!

We will update this page as more information becomes available. Important information (e.g when we have decided on a date for this) will also be sent via email to all Sigma users.

If you have questions not answered on this page

Contact NSC Support and ask us!