[Pacemaker] Best way to recover from failed STONITH?

Fri Dec 21 13:47:39 EST 2012

Andreas,

Thanks for the help. Please see my replies inline below.

----- Original Message -----
> From: "Andreas Kurz" <andreas at hastexo.com>
> To: pacemaker at oss.clusterlabs.org
> Sent: Friday, December 21, 2012 10:11:08 AM
> Subject: Re: [Pacemaker] Best way to recover from failed STONITH?
> 
> On 12/21/2012 04:18 PM, Andrew Martin wrote:
> > Hello,
> > 
> > Yesterday a power failure took out one of the nodes and its STONITH
> > device (they share an upstream power source) in a 3-node
> > active/passive cluster (Corosync 2.1.0, Pacemaker 1.1.8). After
> > logging into the cluster, I saw that the STONITH operation had
> > given up in failure and that none of the resources were running on
> > the other nodes:
> > Dec 20 17:59:14 [18909] quorumnode       crmd:   notice:
> > too_many_st_failures:       Too many failures to fence node0 (11),
> > giving up
> > 
> > I brought the failed node back online and it rejoined the cluster,
> > but no more STONITH attempts were made and the resources remained
> > stopped. Eventually I set stonith-enabled="false" ran killall on
> > all pacemaker-related processes on the other (remaining) nodes,
> > then restarted pacemaker, and the resources successfully migrated
> > to one of the other nodes. This seems like a rather invasive
> > technique. My questions about this type of situation are:
> >  - is there a better way to tell the cluster "I have manually
> >  confirmed this node is dead/safe"? I see there is the meatclient
> >  command, but can that only be used with the meatware STONITH
> >  plugin?
> 
> crm node cleanup quorumnode

I'm using the latest version of crmsh (1.2.1) but it doesn't seem to support this command:
root at node0:~# crm --version
1.2.1 (Build unknown)
root at node0:~# crm node
crm(live)node# help

Node management and status commands.

Available commands:

	status           show nodes' status as XML
	show             show node
	standby          put node into standby
	online           set node online
	fence            fence node
	clearstate       Clear node state
	delete           delete node
	attribute        manage attributes
	utilization      manage utilization attributes
	status-attr      manage status attributes
	help             show help (help topics for list of topics)
	end              go back one level
	quit             exit the program
Also, do I run cleanup on just the node that failed, or all of them?

> 
> >  - in general, is there a way to force the cluster to start
> >  resources, if you just need to get them back online and as a
> >  human have confirmed that things are okay? Something like crm
> >  resource start rsc --force?
> 
> ... see above ;-)

On a related note, is there a way to way to get better information
about why the cluster is in its current state? For example, in this 
situation it would be nice to be able to run a command and have the
cluster print "resources stopped until node XXX can be fenced" to
be able to quickly assess the problem with the cluster.

> 
> >  - how can I completely clear out saved data for the cluster and
> >  start over from scratch (last-resort option)? Stopping pacemaker
> >  and removing everything from /var/lib/pacemaker/cib and
> >  /var/lib/pacemaker/pengine cleans the CIB, but the nodes end up
> >  sitting in the "pending" state for a very long time (30 minutes
> >  or more). Am I missing another directory that needs to be
> >  cleared?
> 
> you started with an completely empty cib and the two (or three?)
> nodes
> needed 30min to form a cluster?
Yes, in fact I cleared out both /var/lib/pacemaker/cib and /var/lib/pacemaker/pengine
several times and most of the times after starting pacemaker again
one node would become "online" pretty quickly (less than 5 minutes), but the other two 
would remain "pending" for quite some time. I left it going overnight
and this morning all of the nodes
> 
> > 
> > I am going to look into making the power source for the STONITH
> > device independent of the power source for the node itself,
> > however even with that setup there's still a chance that something
> > could take out both power sources at the same time, in which case
> > manual intervention and confirmation that the node is dead would
> > be required.
> 
> Pacemaker 1.1.8 supports (again) stonith topologies ... so more than
> one
> fencing device and they can be "logically" combined.

Where can I find documentation on STONITH topologies and configuring
more than one fencing device for a single node? I don't see it mentioned
in the Cluster Labs documentation (Clusters from Scratch or Pacemaker Explained).

Thanks,

Andrew

> 
> Regards,
> Andreas
> 
> --
> Need help with Pacemaker?
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> 
> > 
> > Thanks,
> > 
> > Andrew
> > 
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> > 
> 
> 
> 
> 
> 
> 
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