Symptom:
>From our about 50 machines (all identical setup, different hardware) running
42.1, within 2 weeks of the last reboot about 10 are affected. At some point
all calls to systemd fail, like
  dbus[882]: [system] Failed to activate service 'org.freedesktop.systemd1':
timed out
There are no other related log messages hinting to a problem in systemd before.

This seems to happen independently of the use of the machine.

Systemd won't respond to anything after that. All systemctl calls fail, ''kill
1'' and ''kill -9 1'' don't work, also reboot/shutdown won't work. Rebooting
the machine fixes the problem temporarily.

Do you have suggestions how to debug this? So far we haven't found a way to
trigger the issue and waiting weeks with many machines potentially failing
isn't a nice option.