[ClusterLabs] Trying to Understanding crm-fence-peer.sh

Bryan K. Walton bwalton+1546953805 at leepfrog.com
Wed Jan 16 15:03:21 UTC 2019


I have posed this question on the DRBD-user list, but didn't receive a
response.

I'm using DRBD 8.4 with Pacemaker in a two node cluster, with a
single primary and fabric fencing.

Almost all of my STONITH testing has worked as I would expect it to.  I
get expected results when I use iptables to sever the replication link,
when I force a kernel panic, and when I trigger an unclean
shutdown/reboot with sysrq trigger.  The fact that my iptables test
results in a fenced node, would seem to suggest that crm-fence-peer.sh
is working as expected.

However, if I issue a simple reboot command on my current primary node
(storage1), what I see is that Pacemaker successfully fails over to the
secondary node.  But the logs on storage2 show the following:

Jan 11 08:49:53 storage2 kernel: drbd r0: helper command: /sbin/drbdadm
fence-peer r0
Jan 11 08:49:53 storage2 crm-fence-peer.sh[15594]:
DRBD_CONF=/etc/drbd.conf DRBD_DONT_WARN_ON_VERSION_MISMATCH=1
DRBD_MINOR=1 DRBD_PEER=storage1 DRBD_PEERS=storage1
DRBD_PEER_ADDRESS=192.168.0.2 DRBD_PEER_AF=ipv4 DRBD_RESOURCE=r0
UP_TO_DATE_NODES='' /usr/lib/drbd/crm-fence-peer.sh
Jan 11 08:49:53 storage2 crm-fence-peer.sh[15594]: INFO peer is
reachable, my disk is UpToDate: placed constraint
'drbd-fence-by-handler-r0-StorageClusterClone'
Jan 11 08:49:53 storage2 kernel: drbd r0: helper command: /sbin/drbdadm
fence-peer r0 exit code 4 (0x400)
Jan 11 08:49:53 storage2 kernel: drbd r0: fence-peer helper returned 4
(peer was fenced)

The exit code 4 would seem to suggest that storage1 should be fenced.
But the switch ports connected to storage1 are still enabled.

Am I misreading the logs here?  This is a clean reboot, maybe fencing
isn't supposed to happen in this situation?  But the logs seem to
suggest otherwise.

Thanks!
Bryan Walton

-- 
Bryan K. Walton                                           319-337-3877 
Linux Systems Administrator                 Leepfrog Technologies, Inc 

----- End forwarded message -----

-- 
Bryan K. Walton                                           319-337-3877 
Linux Systems Administrator                 Leepfrog Technologies, Inc 


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