How to JBoss/Blazeds clustering and channel failover

Question

Hi, I'm stuck with jboss and blazeds clusterization. What I have now is :

1. 2 Jboss Instances, running in all mode
2. One load balancer with apache and mod_jk, as suggested by Jboss docs
3. A spring/flex integration app
4. A flex application that I do not want to throw errors when one of my JBoss instances falls

I find Adobe documentation really lacking, and being new at clustering, jgroups and balancing I cannot find how to deploy my app in clustered environment.

Actually this solution is working fine with remote calls. If one of jboss instances goes down the rpc gets routed to the other instance. What is not working are push messages, cause if client is connected to JBossA, and JBossA goes down, client displays an error message, stating that it can't reach JBossA, when it should failover to JBossB, without the user noticing anything.

From what I understood if configured correctly blazeds should tell flex client about failover servers upon connection. Then if flex client can't connect to the main server it goes to another. But the hard part for me is getting there. Can someone point me to the right direction? Thanks in advance

Answer 1

If you have an apache web server sitting between the clients and the JBoss servers, with mod_jk handling communication between apache and JBoss, then that should be your failover requirements met already.

mod_jk will detect if any of the JBoss servers fails, and send requests to the other one. As far as the clients are concerned, they see a single server, which is the apache server. They see nothing of the JBoss servers behind it.

I know nothing about BlazeDS clustering, but I'm guessing it has some form of manual failover mechanism, which it tells clients about a list of server addresses, and the clients pick one that works. This should only be necessary if you don't have a mod_jk middleman, so hopefully you can just ignore the blazeds clustering.

Things can, of course, get a lot more complicated, such as when you need to JBoss servers to commnunicate amongst themselves (e.g. session replication, clustered JMS, distributed caching, etc), but if you don't need any of that, then you can safely ignore it.