systemd units created by Ignition don't have their symlinks created

[arithx]

Ignition expects that systemd-preset will run and take care of creating relevant symlinks.

As a result currently any systemd unit created by Ignition will not run despite being enabled.

Per @cgwalters systemd-preset won't run on RHCOS:
that's another consequence of the ConditionFirstBoot= not being set - it only works for systems with empty /etc (neither classic fedora/rhel nor ostree-based systems)

[cgwalters]

It might be simplest to change Ignition to run systemctl preset only for those units that it creates.

Alternatively, we could try to change things so that we don't do any presets when building images and do it on first boot. I'm...uncertain about the complexity of that.

[peterbaouoft]

Related: coreos/bugs#2244

[peterbaouoft]

coreos/ignition-dracut#11 also seems to be related?

Update: yup, can close this issue once the PR gets merged i think.

[cgwalters]

This was fixed.

[peterbaouoft]

Yup, can confirm it, I see the following behaivor on the newly built ami image. The ami id is ami-0918132e44967d193, built on July 27th

[root@ip-172-18-10-219 ~]# journalctl -xe | grep preset
Jun 27 20:25:45 localhost.localdomain systemd[1]: Populated /etc with preset unit settings.
[root@ip-172-18-10-219 ~]# rpm-ostree status 
State: idle; auto updates disabled
Deployments:
* ostree://rhcos:openshift/3.10/x86_64/os
                   Version: 3.10-7.5.165 (2018-06-27 09:27:44)
                    Commit: 05b032f3aab81ef961500861435731d6de847fd89e2e7de2e99b55274901492c