apt dist-upgrade freezes on disco daily

[Karl Stenerud]

[Impact]

Attempting to do a dist-upgrade on a disco container causes it to hang. This has been a problem on and off for about a year: https://askubuntu.com/questions/1037431/receiving-the-error-snapd-snap-repair-service-is-a-disabled-or-a-static-unit-n

[Test Case]

lxc launch ubuntu-daily:disco tester && lxc exec tester bash
apt update && apt dist-upgrade -y

It gets to snap and then freezes:

Setting up snapd (2.37.2+19.04) ...
Installing new version of config file /etc/apparmor.d/usr.lib.snapd.snap-confine.real ...
snapd.failure.service is a disabled or a static unit, not starting it.
snapd.snap-repair.service is a disabled or a static unit, not starting it.

[Regression Potential]

This seems to be intermittent on certain snapd upgrades. It's hard to say how it would be affected. Since it's a standard container upgrade, it can affect all disco containers.

[Karl Stenerud (kstenerud)]

This is probably a snapd issue rather than lxd. I've posted a bug report here: https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1815173

[Stéphane Graber (stgraber)]

Closing the LXD side of this (tasks would likely have been better) as there's indeed nothing particularly special that LXD does here and usually the right approach is to track down what the package in question is doing and fix it there.