Recently we upgraded our systems from Flatcar stable 3815.2.5 to Flatcar 3975.2.0. This means we moved from systemd version 252 to 255.
Our systems are configured with a custom default target called online.target.
ls -l /etc/systemd/system/default.target
lrwxrwxrwx. 1 root root 33 Aug 16 09:41 /etc/systemd/system/default.target -> /etc/systemd/system/online.target
Two services depend on this target by means of a WantedBy=online.target in their respective service files. One is a Type=oneshot service which runs a custom activation-check.sh script, the other is a Type=exec service which runs the Bird routing daemon.
In addition, there is a directory /etc/systemd/system/online.target.wants which contains symlinks to the services mentioned earlier.
The problem is that the system says it has succesfully reached online.target, but the activation-check.service was never started.
Logging says:
Aug 16 09:44:09 dev-ns01 systemd[1]: Reached target multi-user.target - Multi-User System.
Aug 16 09:44:09 dev-ns01 systemd[1]: Reached target online.target
However, when I manually change to the online target using systemctl isolate online.target everything works perfectly fine. So that tells me the dependencies are configured correctly, right?
I have looked through the changelog from systemd 252 to 255 but have found nothing related to this issue. Anybody have a clue?