Status

• EL9 at Zeuthen will become the default and recommended Linux version:
  • Users and groups are encouraged to test their software packages for EL9-compliance

• DESY's EL9 distribution is currently based on AlmaLinux

• A test system is accessible via the alias name el9.zeuthen.desy.de. It has been set up with a WGS configuration and is meant to be used for tests and development, not for running production jobs.

• Another way to try EL9 is to use the Apptainer container, which is possible on WGSs, compute nodes and even Linux desktops.

• For EL9-based desktop systems see below.

EL9 presentations

• none yet

Changes w.r.t. SL7 from the user's point of view

Enhancements

• IPv6 (dual stack) is enabled by default on all systems (desktops, wgs, batch farm nodes)

Changes regarding software

• The new default compiler version is GCC 11.3

Known Problems

• none, yet

Desktops

Here are a few facts users of EL desktops should be aware of:

Access

• All user accounts valid at DESY Zeuthen can log in on the local graphical login screen.
• No remote access via ssh.

Local Home Directory

• Home directories reside on the local disk.

  • Please note that local disks are not redundant and may break or vanish otherwise anytime.

• There is no central backup.

  • It is recommended to arrange for a personal backup of the home directory with vorta. The software is installed by default.
• There is a 4 GB home quota.
  • We need to set a quota to keep things manageable. It avoids problems when desktops are used by more than one user, which is still a frequent case, and also keeps making backups feasible and consume reasonable amounts of resources.

If downloads etc. don't fit into the home directory, there's more local space available in /tmp. Files there will be cleaned up two weeks after they were last accessed. Unlike "usual" RHEL installations, /tmp/ is not cleared when our systems are rebooted.

AFS Client

• The AFS client is installed by default, the local directories are available at '/afs/ifh.de'

Adding and Removing Software Packages

• Local users can install software from the configured repositories of permitted package sources.
  • These changes are not saved or recorded centrally, and will vanish when a system is reinstalled.

  • There is considerable potential for getting the system into a bad state, thus this feature should be used with care and thought.

  • The graphical user interface 'Software' is in the menu by default.

• On the command line, you can use the pkcon(1) command. Just translate sudo dnf install <package> into pkcon install <package>.

• You can also install third-party software using the command flatpak(1). The Zoom client is already installed using flatpak, to install Google Chrome, type flatpak install com.google.chrome

Remote access to the Windows Terminal server

If you don't want to use the web access, use the preinstalled version of remmina.

Reinstallation

• Anyone with access to the local console can reinstall the desktop from scratch. Requesting a network (PXE) boot during startup will result in presentation of a menu with all available desktop OS options to choose from.

• Note that a reinstallation will wipe the local disk and any prior content will be lost irrecoverably.

Miscellania

• While GNOME3 (gnome-shell) is the default and recommended desktop environment, it is possible though to install a plethora of others from the configured repos.

Known Issues

• Firefox cannot play some videos, e.g. from the ARD Mediathek.
• Screen sharing doesn't work from the Zoom client, you have to join the meeting in Firefox to share your screen or a window.