I was able to write custom script/program to fence and unfence node in the cluster, simply by putting this script on /usr/sbin directory and calling from cluster suite by agent=fence_foo parameter (full path /usr/sbin/fence_foo). But on documentation this functionality isn't reported. It's possible to document this capabilities?
Perry, Lon, Sayan:
I'm not sure whether we want to be documenting custom fencing scripts. Any thoughts or input? It won't make 6.2, in any case, but I don't know where to take this.
Moving this to 6.3 for now until we can determine whether this is something we want to document. But, as noted, it won't be ready for 6.2.
We do not support users adding custom fencing scripts to RHEL HA clusters, so while it is theoretically possible to make this work (as Comment #0 indicates), it would not make sense to document something that we don't yet support.
One of the issues with adding a fence device in the way described above is that we maintain a rng schema that is used to validate the cluster.conf file, and adding a new fence agent would require the scheme to be updated, which cannot be done dynamically or by an end user
The proper way to handle a new fence agent is to introduce the new agent upstream, and submit a feature request to bring it into RHEL and be supported.
Sayan, do you agree or disagree with this analysis? I'll defer to you here.
Pinging Sayan on this: I'd like to close this out as part of RHEL 6.3 planning, but I'm waiting for your response to Perry's Comment#4.
Moving this to 6.4 -- I'm pretty certain we are going to close it as WONTFIX based on the discussion, but it's still in NEEDINFO based on Perry's question to Sayan in Comment 4. So for administrative reasons (we're up against 6.3 beta and this appears as a ping) I'm just moving it ahead.
But, as noted, I'm pretty certain we just won't be adding this information to the cluster administration document, but I won't officially close it without the sign-off of agreement on that course of action.
Closing this as WONTFIX, since we don't support users adding custom fencing scripts to RHEL HA clusters.