Know issues and common errors

Use systemctl restart systemd-sysext.service to refresh sysexts on Fedora 41

On Fedora 41 based images, make sure to use systemctl restart systemd-sysext.service instead of systemd-sysext merge. systemd-sysext unmerge is safe to use.

This issue is fixed in systemd v257 which landed in Fedora 42. See:

• https://github.com/coreos/fedora-coreos-tracker/issues/1744
• https://github.com/systemd/systemd/issues/34387
• https://github.com/systemd/systemd/pull/34414
• https://github.com/systemd/systemd/pull/35132

Current limitation of systemd-sysupdate

While installing and updating via systemd-sysupdate works, this also has a few limitations:

• The sysexts are enabled “statically” for all deplpoyments and if you rebase between major Fedora versions, the sysexts will not match the Fedora release and will not be loaded until you update again using systemd-sysupdate.
• The SELinux policy is currently incomplete for systemd-importd, used by systemd-sysupdate, which thus prevent us from running updates as a service in the background for now. See:
  • https://github.com/fedora-selinux/selinux-policy/pull/2604
  • https://github.com/fedora-selinux/selinux-policy/issues/2622

Failed to read metadata for image …: No medium found

If you encounter this error, it likely means that you have set your sysext image with the full name in the /var/lib/extensions directory. systemd-sysext expects the sysexts images to be named only with their own name, without any version (thus why we use the /var/lib/extensions.d directory in the general case).