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On 10/21/2014 06:44 AM, Balázs Gibizer wrote:
> Hi, 
> 
> Sorry for the top posting but it was hard to fit my complete view inline.
> 
> I'm also thinking about a possible solution for automatic server
> evacuation. I see two separate sub problems of this problem:
> 1)compute node monitoring and fencing, 2)automatic server evacuation
> 
> Compute node monitoring is currently implemented in servicegroup
> module of nova. As far as I understand pacemaker is the proposed
> solution in this thread to solve both monitoring and fencing but we
> tried and found out that pacemaker_remote on baremetal does not work
> together with fencing (yet), see [1]. So if we need fencing then
> either we have to go for normal pacemaker instead of pacemaker_remote
> but that solution doesn't scale or we configure and call stonith
> directly when pacemaker detect the compute node failure. 

I didn't get the same conclusion from the link you reference.  It says:

"That is not to say however that fencing of a baremetal node works any
differently than that of a normal cluster-node. The Pacemaker policy
engine understands how to fence baremetal remote-nodes. As long as a
fencing device exists, the cluster is capable of ensuring baremetal
nodes are fenced in the exact same way as normal cluster-nodes are fenced."

So, it sounds like the core pacemaker cluster can fence the node to me.
 I CC'd David Vossel, a pacemaker developer, to see if he can help clarify.

-- 
Russell Bryant