Frontend and Compute Node Maintenance

from 8.7.2026 - Frontend and Compute Node Maintenance

Due to the deployment of kernel security update, Debian 12 frontend servers will be rebooted in a rolling manner. Direct logins to some worker nodes will also be temporarily restricted.

What does this mean for users?

Temporary restriction of direct login to compute nodes – Direct user logins to compute nodes will be temporarily disabled (nologin ) to minimize the risk of exploitation until all affected systems have been updated. Running jobs will be allowed to complete normally.
Frontend servers will be restarted in a controlled, rolling manner after the security updates have been deployed.
As part of the maintenance, the skirit and perian frontend servers will also be upgraded to Debian 13.

Important notice: SSH key changes

In connection with the frontend upgrade to Debian 13, your SSH client may warn you about a change in host keys (fingerprints). This is expected behavior. You can verify the official list of SSH keys in our documentation:

https://docs.metacentrum.cz/en/docs/access/security/connect-auth

We apologize for any temporary inconvenience and appreciate your understanding. Maintaining the security and reliability of our infrastructure remains our highest priority.

Ivana Křenková, 8. 7. 2026