[ClusterLabs] I question whether STONITH is working.

Ken Gaillot kgaillot at redhat.com
Wed Feb 15 16:30:35 EST 2017

On 02/15/2017 12:17 PM, durwin at mgtsciences.com wrote:
> I have 2 Fedora VMs (node1, and node2) running on a Windows 10 machine
> using Virtualbox.
> I began with this.
> http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Clusters_from_Scratch/
> When it came to fencing, I refered to this.
> http://www.linux-ha.org/wiki/SBD_Fencing
> To the file /etc/sysconfig/sbd I added these lines.
> SBD_DEVICE="/dev/sdb1"
> I added 'modprobe softdog' to rc.local
> After getting sbd working, I resumed with Clusters from Scratch, chapter
> 8.3.
> I executed these commands *only* one node1.  Am I suppose to run any of
> these commands on other nodes? 'Clusters from Scratch' does not specify.

Configuration commands only need to be run once. The cluster
synchronizes all changes across the cluster.

> pcs cluster cib stonith_cfg
> pcs -f stonith_cfg stonith create sbd-fence fence_sbd
> devices="/dev/sdb1" port="node2"

The above command creates a fence device configured to kill node2 -- but
it doesn't tell the cluster which nodes the device can be used to kill.
Thus, even if you try to fence node1, it will use this device, and node2
will be shot.

The pcmk_host_list parameter specifies which nodes the device can kill.
If not specified, the device will be used to kill any node. So, just add
pcmk_host_list=node2 here.

You'll need to configure a separate device to fence node1.

I haven't used fence_sbd, so I don't know if there's a way to configure
it as one device that can kill both nodes.

> pcs -f stonith_cfg property set stonith-enabled=true
> pcs cluster cib-push stonith_cfg
> I then tried this command from node1.
> stonith_admin --reboot node2
> Node2 did not reboot or even shutdown. the command 'sbd -d /dev/sdb1
> list' showed node2 as off, but I was still logged into it (cluster
> status on node2 showed not running).
> I rebooted and ran this command on node 2 and started cluster.
> sbd -d /dev/sdb1 message node2 clear
> If I ran this command on node2, node2 rebooted.
> stonith_admin --reboot node1
> What have I missed or done wrong?
> Thank you,
> Durwin F. De La Rue
> Management Sciences, Inc.
> 6022 Constitution Ave. NE
> Albuquerque, NM  87110
> Phone (505) 255-8611

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