[ClusterLabs] How to cancel a fencing request?

[Andrei Borzenkov]

04.04.2018 01:35, Ken Gaillot пишет:
> On Tue, 2018-04-03 at 21:46 +0200, Klaus Wenninger wrote:
...
>>>>>>
>>>>
>>>> -inf constraints like that should effectively prevent
>>>> stonith-actions from being executed on that nodes.
>>>
>>> It shouldn't ...
>>>
>>> Pacemaker respects target-role=Started/Stopped for controlling
>>> execution of fence devices, but location (or even whether the
>>> device is
>>> "running" at all) only affects monitors, not execution.
>>>
>>>> Though there are a few issues with location constraints
>>>> and stonith-devices.
>>>>
>>>> When stonithd brings up the devices from the cib it
>>>> runs the parts of pengine that fully evaluate these
>>>> constraints and it would disable the stonith-device
>>>> if the resource is unrunable on that node.
>>>
>>> That should be true only for target-role, not everything that
>>> affects
>>> runnability
>>
>> cib_device_update bails out via a removal of the device if
>> - role == stopped
>> - node not in allowed_nodes-list of stonith-resource
>> - weight is negative
>>
>> Wouldn't that include a -inf rule for a node?
> 
> Well, I'll be ... I thought I understood what was going on there. :-)
> You're right.
> 
> I've frequently seen it recommended to ban fence devices from their
> target when using one device per target. Perhaps it would be better to
> give a lower (but positive) score on the target compared to the other
> node(s), so it can be used when no other nodes are available.
> 

Oh! So I must have misunderstood comments on this in earlier discussions.

So ability to place stonith resource on node does impact ability to
perform stonith using this resource, right? OTOH decision which node is
eligible to use stonith resource for stonith may not match decision
which node is eligible to start stonith resource? Even more confusing ...

>> It is of course clear that no pengine-decision to start
>> a stonith-resource is required for it to be used for
>> fencing.
>>

This means that there is only subset of usual (co-)locating restrictions
that is taken into account? Is it all documented somewhere?