[ClusterLabs] Antw: changing constraints and checking quorum at the same time

[Ulrich Windl]

>>> Christopher Harvey <cwh at eml.cc> schrieb am 04.10.2016 um 22:36 in Nachricht
<1475613371.3482889.745895529.6D249A15 at webmail.messagingengine.com>:
> I was wondering if it is possible to ask pacemaker to add a resource
> constraint and make sure that the majority of the cluster sees this
> constraint modification or fail if quorum is not achieved.
> 
> This is from within the context of a program issuing pacemaker commands,
> not an operator, so race conditions are my main concern.
> 
> If I cannot "set-and-check" a constraint modification using pacemaker
> alone, is there some kind of sequence of bash commands that I could run
> that would guarantee adequate propagation of my constraint?

I think you need to look at "config" and "action" separately: Action starts after the config changed. The config change is more or less immediate, but action may take a while. Impatience is an especially bad thing for pacemaker clusters it seems (i.e.: Don't start new actions (via config changes)  before old actions are completed (according to the current config).

> 
> Thanks,
> Chris
> 
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