[jboss-user] [Clustering/JBoss] - Re: HASingletonElectionPolicy

[smeng@unique]

Just to add that I have also tried using HASingletonElectionPolicySimple instead of my own customised policy i.e. HASingletonElectionPolicyUnique

First MBean in jboss-service.xml replaced with the following:
    <mbean code="org.jboss.ha.singleton.HASingletonElectionPolicySimple"
  |           name="com.unique.ha:name=HASingletonElectionPolicyUnique">
  |     	<attribute name="Position">0</attribute>
  |    </mbean>

Node A was set with Position 0 and Node B was set with Position 1. 

The results were almost the same with the exception that in between bringing up and down the nodes, the two nodes seemed to have got themselves in a confused state on who is the master and at one point, the application was started on both nodes despite the HASingleton implementation.

The following steps are what I have observed when Node A and B are both running with Node A running as the master. And then I properly shutdown Node A:
1. Node A begins shutdown.
2. Node B detects/informed by Node A?? that Node A is undergoing shutdown.
3. Node B runs the HASingletonElectionPolicy but due to the fact that Node A is still in view, picks Node A as the master.
4. Node B's view changes and notes that Node A is not within the cluster view anymore.

After that, nothing happens and the application doesn't get started at all. Note that if an improper termination of Node A occurs, Node B does start the application, which is correct failover behaviour. The problem only occurs for proper shutdown of nodes.

Is this behaviour correct? Is there a way to manually activate the HASingletonElectionPolicy or some way to get the current state of the other cluster node?

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