[ClusterLabs] best practice fencing with ipmi in 2node-setups / cloneresource/monitor/timeout

[Digimer]

On 20/09/16 06:59 AM, Stefan Bauer wrote:
> Hi,
> 
> i run a 2 node cluster and want to be save in split-brain scenarios. For
> this i setup external/ipmi to stonith the other node.

Please use 'fence_ipmilan'. I believe that the older external/ipmi are
deprecated (someone correct me if I am wrong on this).

> Some possible issues jumped to my mind and i would ike to find the best
> practice solution:
> 
> - I have a primitive for each node to stonith. Many documents and guides
> recommend to never let them run on the host it should fence. I would
> setup clone resources to avoid dealing with locations that would also
> influence scoring. Does that make sense?

Since v1.1.10 of pacemaker, you don't have to worry about this.
Pacemaker is smart enough to know where to run a fence call from in
order to terminate a target.

> - Monitoring operation on the stonith primitive is dangerous. I read
> that if monitor operations fail for the stonith device, stonith action
> is triggered. I think its not clever to give the cluster the option to
> fence a node just because it has an issue to monitor a fence device.
> That should not be a reason to shutdown a node. What is your opinion on
> this? Can i just set the primitive monitor operation to disabled?

Monitoring is how you will detect that, for example, the IPMI cable
failed or was unplugged. I do not believe the node will get fenced on
fence agent monitor failing... At least not by default.


-- 
Digimer
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