(systemd version 229, fwiw)
I have a primary service A, and a secondary service B. The primary A can run by itself. But service B cannot run correctly by itself: it needs A to be running (technically B can run, but this is what I want systemd to prevent). My goal: If A is not running, B should not run. Given that A and B are running, when A stops or dies/crashes, then B should be stopped.
How do I achieve this?
I get close by adding [Unit] items to b.service, using
The result of the above is that
1) B won't start unless A is running (good). 2) B is stopped when A is stopped (good). 3) However, if I kill A, service B continues to run (bad).
How can I fix this last behavior #3? I tried using BindsTo instead of Requisite, like this in B's service file:
and I get:
1) If A is not running and I start B, then A is also started (I want an error, I don't want A started) 2) B is stopped when A is stopped (good). 3) B is stopped when A is killed (good)
So now #3 is good but #1 is not the desired behaviour. Neither PartOf nor BindsTo seems to do the trick, but perhaps I don't have the right incantation of combinations of options? Its not clear to me from the man pages what options can be combined.
With BindsTo, I also tried failing B's start using ExecStartPre, but of course this didn't work because the start of B had already determined that it needed A to run (and started it), before it fired up B.
Is there some way to get a behaviour inbetween Requisite and BindsTo? The 1-2-3 I've listed above?
Thanx in advance!