[Pacemaker] best/proper way to shut down a node for service

Dan Frincu df.cluster at gmail.com
Thu Jan 24 03:04:55 EST 2013


On Wed, Jan 23, 2013 at 11:28 PM, Brian J. Murrell
<brian at interlinx.bc.ca> wrote:
> On 13-01-23 03:32 AM, Dan Frincu wrote:
>> Hi,
> Hi,
>> I usually put the node in standby, which means it can no longer run
>> any resources on it. Both Pacemaker and Corosync continue to run, node
>> provides quorum.
> But a node in standby will still be STONITHed if it goes AWOL.  I put a
> node in standby and then yanked it's power and it's peer started STONITH
> operations on it.  That's the part I want to avoid.

You have to explain what AWOL means in this context, even in a 2-node
cluster, putting one node in standby without changing no-quorum-policy
to ignore or setting stonith-enabled=false will just move off the
resources from the node.

Failure to stop a resource running on a node which is in the shutdown
procedure (which means resources will be stopped - shutting down
Pacemaker or by putting the node in standby would have the same effect
on the resources, telling them to stop) will lead to STONITH.

So just to emphasize this again, if there is a stop failure,
regardless of how you turn off the resource (Pacemaker shutdown,
putting the node in standby, telling the resource to move to another
node, etc.), that will STONITH the node.

Now, going back to no-quorum-policy, default action is stop, so in a
2-node cluster, if you shutdown Pacemaker without setting
no-quorum-policy to ignore, when quorum is lost, resources on the
remaining node stop. By putting the node in standby, quorum is still
met, this does not take place.

Once a node is in standby, if you want to stop pacemaker and corosync,
that won't lead into the "node running AWOL" situation you've
mentioned earlier.

Having more than 2 nodes in a cluster means shutdown of pacemaker and
corosync/putting the node in standby won't affect quorum as the other
nodes still work.

Either way, choose whatever fits your requirement best, I just added
some comments related to how this would work and what would be the
possible problems in a 2-node cluster.


> b.
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Dan Frincu

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