[Pacemaker] How to setup STONITH in a 2-node active/passive linux HA pacemaker cluster?

[Dejan Muhamedagic]

Hi,

On Tue, Mar 20, 2012 at 08:52:39AM +0100, Mathias Nestler wrote:
> On 19.03.2012, at 20:26, Florian Haas wrote:
> 
> > On Mon, Mar 19, 2012 at 8:14 PM, Mathias Nestler
> > <mathias.nestler at barzahlen.de> wrote:
> >> Hi everyone,
> >> 
> >> I am trying to setup an active/passive (2 nodes) Linux-HA cluster with corosync and pacemaker to hold a PostgreSQL-Database up and running. It works via DRBD and a service-ip. If node1 fails, node2 should take over. The same if PG runs on node2 and it fails. Everything works fine except the STONITH thing.
> >> 
> >> Between the nodes is an dedicated HA-connection (10.10.10.X), so I have the following interface configuration:
> >> 
> >> eth0                        eth1                   host
> >> 10.10.10.251    172.10.10.1     node1
> >> 10.10.10.252    172.10.10.2     node2
> >> 
> >> Stonith is enabled and I am testing with a ssh-agent to kill nodes.
> >> 
> >> crm configure property stonith-enabled=true
> >> crm configure property stonith-action=poweroff
> >> crm configure rsc_defaults resource-stickiness=100
> >> crm configure property no-quorum-policy=ignore
> >> 
> >> crm configure primitive stonith_postgres stonith:external/ssh \
> >>               params hostlist="node1 node2"
> >> crm configure clone fencing_postgres stonith_postgres
> > 
> > You're missing location constraints, and doing this with 2 primitives
> > rather than 1 clone is usually cleaner. The example below is for
> > external/libvirt rather than external/ssh, but you ought to be able to
> > apply the concept anyhow:
> > 
> > http://www.hastexo.com/resources/hints-and-kinks/fencing-virtual-cluster-nodes
> > 
> 
> As is understood the cluster decides which node has to be stonith'ed. Besides this, I already tried the following configuration:
> 
> crm configure primitive stonith1_postgres stonith:ssh \
> 	params hostlist="node1"
> 	op monitor interval="25" timeout="10"
> crm configure primitive stonith2_postgres stonith:ssh \
> 	params hostlist="node2"
> 	op monitor interval="25" timeout="10"
> crm configure location stonith1_not_on_node1 stonith1_postgres \
> 	-inf: node1
> crm configure location stonith2_not_on_node2 stonith2_postgres \
> 	-inf: node2
> 
> The result is the same :/

Neither ssh nor external/ssh are supported fencing options. Both
include a sleep before reboot which makes the window in which
it's possible for both nodes to fence each other larger than it
is usually the case with production quality stonith plugins.

As for the configuration, I'd rather use the first one, just not
cloned. That also helps prevent mutual fencing.

See also:

http://www.clusterlabs.org/doc/crm_fencing.html
http://ourobengr.com/ha

Thanks,

Dejan

> > Hope this helps.
> > Cheers,
> > Florian
> > 
> 
> Best
> Mathias
> 

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