[Jboss-dev-forums] [Design of Clustering on JBoss (Clusters/JBoss)] - Re: JBAS-2520 - HASingleton stopping problem

[ScottMarlowNovell <do-...@jb...>]

I agree that the root cause of the failure should be solved.  Each occurence of a failure is a separate issue from the HASingleton itself failing.  

My take on recovery:

>a) We cannot stop ourselves

Send a message to event listener indicating that we cannot stop ourselves (this might send email or a beeper notification.)  Let user policy (code or configuration policy determine if we should {terminate server process, ignore error, try again}.  Default action could be ignore.

> b) We cannot start the new master on a different node because we left the cluster or there is no cluster

I think that the current master will attempt stopping itself when HASingletonSupport.partitionTopologyChanged() is invoked.  We could send a message to event listener indicating that we left the cluster or there is no cluster.  I may be reading the current code wrong, but it looks like the remaining cluster will elect a new master (need to verify.)

Let user policy (code or configuration policy determine if we should {terminate server process, ignore error, try again}.  Default action could be ignore.

>c) We cannot start the new master on a different node because of some other error reported by the new master

We could send a message to event listener on the different node indicating that it failed to become master.  Let user policy (code or configuration policy determine if we should {terminate server process, ignore error, try again}.  Default action could be terminate server process so that a new master is chosen.

A nice thing would be if cluster management Failures were defined as an aspect that could be handled consistently across the board.  The problem that I am thinking of is how we deal with failures across the board, do we manually handle the errors or inject handlers that deal with varying qualities of service.  Or perhaps I should be asking if we should wait until we switch to using AOP to attempt across the board handling of failures.

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