[ClusterLabs] I question whether STONITH is working.

Mon Feb 20 15:16:23 EST 2017

Klaus Wenninger <kwenning at redhat.com> wrote on 02/16/2017 03:27:07 AM:

> From: Klaus Wenninger <kwenning at redhat.com>
> To: kgaillot at redhat.com, Cluster Labs - All topics related to open-
> source clustering welcomed <users at clusterlabs.org>
> Date: 02/16/2017 03:27 AM
> Subject: Re: [ClusterLabs] I question whether STONITH is working.
> 
> On 02/15/2017 10:30 PM, Ken Gaillot wrote:
> > 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_OPTS="-W"
> >> 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.
> 
> fence_sbd should return a proper dynamic-list.
> So without ports and host-list it should just work fine.
> Not even a host-map should be needed. Or actually it is not
> supported because if sbd is using different node-naming than
> pacemaker, pacemaker-watcher within sbd is gonna fail.

It was said that 'port=' is not needed, that if I used the command below
it would just work (as I understood what was being said).  So I deleted
using this command.
pcs -f stonith_cfg stonith delete sbd-fence

Recreated without 'port='.
pcs -f stonith_cfg stonith create sbd-fence fence_sbd devices="/dev/sdb1"
pcs cluster cib-push stonith_cfg

>From node2 I executed this command.
stonith_admin --reboot node1

But node2 rebooted anyway.

If I follow what Ken shared, I would need another 'watchdog' in addition
to another sbd device.  Are multiple watchdogs possible?

I am lost at this point.

I have 2 VM nodes running Fedora25 on a Windows 10 host.  Every
node in a cluster needs to be fenced (as I understand it).  Using
SBD, what is the correct way to proceed?

Thank you,

Durwin

> 
> >
> >> 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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