How does the Election Policy Feature work in 4.2.X

[ratrask]

I recently had a problem with no node wanting to become the master. As I investigated the issue I found that there was a back port from 5.0 of a mechanism to control the election policy, but I have found no information about how to use this feature. Below is a snipit from an earlier post on this topic that got burried in the other issue, and desrves an independent post.

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I thought that the problem could be related to the org.jboss.ha.singleton.HASingletonElectionPolicy feature which was back ported from 5.0,
see: http://jira.jboss.com/jira/browse/JBAS-3636

This attribute shows up under the MBean attributes of org.jboss.ha.singleton.HASingletonController from the JMX console, but despite showing the attribute as read / write, you can not change the value. Attempts to set the the value in the deploy/deploy-hasingleton-service.xml file result in a property editor exception.

There is some method that I am not aware of that they have used to test this functionality out in JBoss' test suit, (for example http://www.ohloh.net/projects/480/contributors/26897/commits/6569686 )

[brian.stansberry]

I've never had time to doc this. :-(

See this file in the testsuite for an example of deploying a number of HASingletonController instances, each with a differently configured election policy. The file is fairly self-explanatory -- I hope ;)

The HASingletonController exposes an mbean attribute for the policy, but that's a complex type and can't be edited via the JMX console (nor is it meant to be edited after deployment.)

[belaban]

I'm interested in the documentation here too, because JGroups in version 2.7 will have a pluggable coordinator policy too. We should discuss how the 2 policies will complement each other.

[mohitanchlia]

Is there a document available now? I have been trying to get some document on Election Policy, how it works, what it does etc. But not able to find it anywhere. Could somebody help me with that?