Upgrade from 3510.2.8 to 3815.2.0 does not create /etc/extensions/containerd-flatcar.raw symlink

[richardzuidhof]

Description

After upgrading from release 3510.2.8 to 3815.2.0 the symlinks for containerd/dockerd in /etc/extensions are not created. From 3760.2.0 to 3815.2.0 this issue does not occur.

Impact

After some automated upgrades containerd fails to start

Environment and steps to reproduce

1. Set-up: Running Flatcar 3510.2.8 on Vmware
2. Task: Updating to https://update.release.flatcar-linux.net/amd64-usr/3815.2.0/flatcar_production_update.gz using the update-engine
3. Action(s): Update and reboot
4. Error: After reboot containers would not start because no container engines were running

Expected behavior

When updating to the latest release of Flatcar that uses sysext images the required symlinks should be always be created

Additional information

Please add any information here that does not fit the above format.

[pothos]

I couldn't reproduce this from a fresh VM, can you share more about the setup?

[pothos]

Maybe /etc/extensions/ already existed and had a different mode or other differences that prevent the symlinks from the underlay to show up.
During the update to 3815.2.0 the overlay.opaque attr is already cleared if it had existed, that shouldn't be the problem.

[richardzuidhof]

Very strange indeed. I can not reproduce it anymore either.