systemd-resolve user missing

[Cornelicorn]

Describe the bug
When adding the systemd-resolved module, the service will not start correctly as the systemd-resolve user is missing. This user is used by the service since v235.

Distribution used
Arch rolling

Dracut version
dracut 055

Init system
systemd 249.7-1-arch

To Reproduce
Call dracut with --add systemd-resolved and reboot

Expected behavior
The service should start

Additional context

[johannbg]

This is due to systemd/systemd#20056

[Cornelicorn]

This is due to systemd/systemd#20056

This has not been released yet, as far as I can tell.

I think I found the culprit, systemd-sysusers.service contains ConditionNeedsUpdate=/etc. This will cause the unit to not start, seemingly since it cannot find /etc/.updated. The docs for that condition give a kernel commandline parameter to override this Condition Check. If I add systemd.condition-needs-update=true, systemd-sysusers.service runs and systemd-resolved starts without a problem.

I also found a news entry from systemd mentioning that this Condition will cause units not to be executed in initrd's anymore.

So this seems like a larger issue of systemd-sysusers not running anymore.

[Cornelicorn]

The corresponding check.

[johannbg]

That's an interesting PR which is seemingly based on misconception or total disregard for some of the usecases initrd are used for and basically means we need to start shipping our own type units for the initrd for systemd upstream units ( or overide snippets for them ).

[Cornelicorn]

For the override snippet, it would be enough to install

[Unit]
ConditionNeedsUpdate=

to $systemdsystemunitdir/systemd-sysusers.service.d/sysusers-initrd.conf from modules.d/01systemd-sysusers/module-setup.sh.

I successfully tested this locally.

I can open a PR for this change if you want.

[johannbg]

Yeah sure and it's probably better to have dracut in the unit file name to make it clear that this unit came from dracut ( as opposed to initrd since there are multiple initrd solutions in the wild ) but in the end of the day I dont think we can avoid having to start shipping a full blown systemd units for modules since there are limitation what can be overridden using snippets. + we need to file a upstream bug about this.