[ClusterLabs Developers] RA as a systemd wrapper -- the right way?

[Jan Pokorný]

On 26/09/16 11:39 -0500, Ken Gaillot wrote:
> On 09/26/2016 09:10 AM, Adam Spiers wrote:
>> Now, here I *do* see a potential problem.  If service B is managed by
>> Pacemaker, is configured with Requires=A and After=A, but service A is
>> *not* managed by Pacemaker, we would need to ensure that on system
>> shutdown, systemd would shutdown Pacemaker (and hence B) *before* it
>> (systemd) shuts down A, otherwise A could be stopped before B,
>> effectively pulling the rug from underneath B's feet.
>> 
>> But isn't that an issue even if Pacemaker only uses systemd resources?
>> I don't see how the currently used override files protect against this
>> issue.  Have I just "discovered" a bug, or more likely, is there again
>> a gap in my understanding?
> 
> Systemd handles the dependencies properly here:
> 
> - A must be stopped after B (B's After=A)
> - B must be stopped after pacemaker (B's Before=pacemaker via override)
> - therefore, stop pacemaker, then A (which will be a no-op because
>   pacemaker will already have stopped it), then B

without reading too much about systemd behavior here, shouldn't this be:

- therefore, stop pacemaker, then B (which will be a no-op because
  pacemaker will already have stopped it), then A

(i.e., A and B swapped)?

-- 
Jan (Poki)
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