[ClusterLabs] Howto stonith in the case of any interface failure?

[Ken Gaillot]

On Wed, 2019-10-09 at 09:58 +0200, Kadlecsik József wrote:
> Hello,
> 
> The nodes in our cluster have got backend and frontend interfaces:
> the 
> former ones are for the storage and cluster (corosync) traffic and
> the 
> latter ones are for the public services of KVM guests only.
> 
> One of the nodes has got a failure ("watchdog: BUG: soft lockup -
> CPU#7 
> stuck for 23s"), which resulted that the node could process traffic
> on the 
> backend interface but not on the fronted one. Thus the services
> became 
> unavailable but the cluster thought the node is all right and did
> not 
> stonith it. 
> 
> How could we protect the cluster against such failures?

See the ocf:heartbeat:ethmonitor agent (to monitor the interface
itself) and/or the ocf:pacemaker:ping agent (to monitor reachability of
some IP such as a gateway)

> 
> We could configure a second corosync ring, but that would be a
> redundancy 
> ring only.
> 
> We could setup a second, independent corosync configuration for a
> second 
> pacemaker just with stonith agents. Is it enough to specify the
> cluster 
> name in the corosync config to pair pacemaker to corosync? What about
> the 
> pairing of pacemaker to this corosync instance, how can we tell
> pacemaker 
> to connect to this corosync instance?
> 
> Which is the best way to solve the problem? 
> 
> Best regards,
> Jozsef
> --
> E-mail : kadlecsik.jozsef at wigner.mta.hu
> PGP key: http://www.kfki.hu/~kadlec/pgp_public_key.txt
> Address: Wigner Research Centre for Physics
>          H-1525 Budapest 114, POB. 49, Hungary
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-- 
Ken Gaillot <kgaillot at redhat.com>