[ClusterLabs] Fencing questions.

Arjun Pandey apandepublic at gmail.com
Mon Oct 19 06:53:26 EDT 2015


I am running a 2 node cluster with this config on centos 6.5/6.6  where i
have a multi-state resource foo being run in master/slave mode and  a bunch
of floating IP addresses configured. Additionally i have a collocation
for the IP addr to be collocated with the master.

Please find the following files attached

Issues that i have :-
1. Daemons required for fencing
Earlier we were invoking cman start quorum from pacemaker script which
ensured that fenced / gfs and other daemons are not started. This was ok
since fencing wasn't being handled earlier.

For fencing purpose do we only need the fenced to be started ?  We don't
have any gfs partitions that we want to monitor via pacemaker. My concern
here is that if i use the unmodified script then pacemaker start time
increases significantly. I see a difference of 60 sec from the earlier
startup before service pacemaker status shows up as started.

2. Fencing test cases.
 Based on the internet queries i could find , apart from plugging out the
dedicated cable. The only other case suggested is killing corosync process
on one of the nodes.
Are there any other basic cases that i should look at ?
What about bring up interface down manually ? I understand that this is an
unlikely scenario but i am just looking for more ways to test this out.

3. Testing whether fencing is working or not.
Previously i have been using fence_ilo4 from the shell to test whether the
command is working. I was assuming that similar invocation would be done by
stonith when actual fencing needs to be done.

However based on other threads i could find people also use fence_tool
<node-name> to try this out. According to me this tests out whether fencing
when invoked by fenced for a particular node succeeds or not. Is that valid

Since we are configuring fence_pcmk as the fence device the flow of things
fenced -> fence_pcmk -> stonith -> fence agent.

4. Fencing agent to be used (fence_ipmilan vs fence_ilo4)
Also for ILO fencing i see fence_ilo4 and fence_ipmilan both available. I
had been using fence_ilo4 till now.

I think this mail has multiple questions and i will probably send out
another mail for a few issues i see after fencing takes place.

Thanks in advance
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