systemd: enable bootc-status-updated.target on startup

[jeckersb]

Any services that react to status changes should be idempotent, and
should run on boot. It is likely (but not guaranteed) that during
boot we are in the process of switching from a previous deployment to
a new one, and thus what was previously "staged" is now "booted" and
what was previously "booted" is now "rollback", so anything that cares
about status is going to want to handle that.

Signed-off-by: John Eckersberg [email protected]

[jeckersb]

Actually it's not even firstboot, for example after doing a bootc update and reboot this is required so what was staged becomes booted.

[cgwalters]

In the general case, don't we actually want to trigger bootc-status-updated.target as part of multi-user.target by default?

[jeckersb]

In the general case, don't we actually want to trigger bootc-status-updated.target as part of multi-user.target by default?

Hmm yeah probably. In a perfect world we don't want to trigger it if nothing has changed (you rebooted the system without any sort of update/switch/rollback queued), but I think that's better than it not triggering when the status did change.

[cgwalters]

This heavily relates to a discussion elsewhere for a metadata flag of "is this the first boot of a deployment"? If we had that, then we could key off it in our systemd generator and only enqueue the change notification if we found that.

ref ostreedev/ostree#3032

But for now I think it's actually OK to run on boot by default - most tools that want to hook into this should be idempotent anyways, i.e. they need to handle the case where nothing changed. Not that anything will run by default except for the subman case today anyways.

[cgwalters]

Marking requested-changes per #1041 (comment)

[jeckersb]

Marking requested-changes per #1041 (comment)

Updated to static enable the .target alongside the .path so both will be enabled and activated at boot. Then the centos-stream MR for rhsm should just work, since the target will trigger the service once it's enabled by the preset. Unfortunately this means we'll need another bootc release to land in c10s/c9s before this all works (unless I hack around it temporarily in the base image build, which I would rather not do).

[cgwalters]

Since we're now enabling this default; I think we should probably also add here ConditionPathExists=/run/ostree-booted? In practice it's probably effectively the same, but the difference is that everyone who isn't using bootc will I think see "skipped as condition not met" vs "reached target bootc-status-updated" and I think the former makes more sense.

Alternatively: We could just dynamically enable this from our generator in that condition.

[jeckersb]

👍 good catch, updated