[Pacemaker] no-quorum-policy = demote?

Lars Ellenberg lars.ellenberg at linbit.com
Fri Apr 11 09:05:50 EDT 2014

On Fri, Apr 11, 2014 at 10:02:59AM +0200, Christian Ciach wrote:
> Thank you for pointing me to the environment variables. Unfortunately, none
> of these work in this case. For example: Assume one node is currently the
> master. Then, because of a network failure, this node loses quorum. Because
> "no-quorum-policy" is set to "ignore", this node will keep being a master.
> In this case there is no change of state, thus the notify-function of the
> OCF-agent does not get called by pacemaker. I've already tried this, so I
> am quite sure about that.

Very very hackish idea:

  set monitor interval of the Master role to T seconds
  and "fail" (+demote) if no quorum.

  (or use a dummy resource agent similar to the "ping" RA,
  and update some node attribute from there...
  then have a contraint for the Master role on that node attribute)

  in your promote action,
  	refuse to promote if no quorum
  	sleep 3*T (+ time to demote)
	only then actually promote.

That way, you are "reasonably" sure that,
before you actually promote,
the former master had a chance to notice quorum loss and demote.

But you really should look into booth, or proper fencing.

: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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