isMasterReplica - Distributed Replicant Manager

[darranl]

I have been investigating implementing a service to run on all of the nodes in my cluster but where only one of the nodes is the master.

I have been using the distributed replicant manager to register the service and the isMasterReplica method to identify a master node.

At the moment I have two nodes in the cluster, both call add on the DRM with the same key.

On both nodes I then call isMasterReplica with the key used earlier and both nodes return true.

I have had a look at the isMasterReplica method and I can see why this is happening:-

A Vector of all active nodes is obtained from the partition by calling getCurrentView.

A Vector is obtained containing the nodes replicating the item.

I added some debug messages to the method so that I could test what was happening and I have found that for some reason one of my nodes in the Vector returned by the partition has had it's name converted to upper case. The Vector containing the nodes replicating the item contains the name in lower case.

This was using JBoss 3.2.1 with Sun JDK 1.4.1_03.

The machine what had the case of it's name changed is a RedHat 7.3 machine, does anyone know what might be causing the name to be changed.

[weiqingh]

isMasterReplica never worked for me, same result as your test -- two servers both returned true.

http://www.jboss.org/modules/bb/index.html?module=bb&op=viewtopic&t= said he could get it to work though...

let me know if you figure this out.

[darranl]

Just wanted to check did anyone get any further with this or should it be raised as a bug at sourceforge?

[slaboure]

make sure your 2 nodes are REALLY part of the same network (i.e. the cluster communication is working) and if it is a small test case is appreciated as it works for me.

cheers


sacha

[darranl]

Yes the two nodes are definately part of the same cluster.

I start the nodes one at a time so that I can see on the first node that the second node has joined the cluster, also I use farming to deploy my application and that also works without any problems.

It is just the isMasterReplica method call that does not work correctly.

When I output the content of both vectors they both contain the names of the other nodes it is just the fact that the case for one of them is different.

When you test this problem which operating system(s) do you use, from my experience and the experience of others in this forum it appears to happen when one node is on a Windows machine and the other node is on a RedHat Linux machine. I am not sure about other linux distributions as that is the only one that I have tested.

I have a simple MBean that I have been using to test this (Just need to find where I have put it), I will post it on here later.

[slaboure]

OK, I see what you mean, please keep me updated on this! [e-mail]

[slaboure]

Interesting, please keep me updated on this ([e-mail]).

Cheers,
sacha