Redirect URL in a cluster

[tiagodfsouza]

We are  developing an application that has a module specific reports, which consumes a  lot of server processing.

We currently  have 3 servers in the cluster, and we would like to stay a dedicated server for reporting.

How to do it  using the cluster's own infrastructure?

[wdfink]

What kind of application WAR or EJB?

[tiagodfsouza]

My application is EJB 3.

To give some more clarifications, I implemented the LoadBalancePolicy, and I  have done the setup to use him in cluster-service.xml jboss, as follows:

<attribute name="LoadBalancePolicy">my.package.loadbalance.SiopLoadBalancePolicy</attribute>

In the ejb3-interceptors-aop.xml, I set the fallow rule:

<domain name="Stateless Bean">
     (...)
     <annotation expr="class(@org.jboss.annotation.ejb.Clustered)">
          @org.jboss.annotation.ejb.Clustered (loadBalancePolicy=my.package.loadbalance.SiopLoadBalancePolicy.class, partition="DefaultPartition")
      </annotation>
</domain>

I add theanotation @Clustered in EJB would like it to be "clustered".

@Stateless(mappedName = "RelatorioServico")
@Clustered

When I start the JBoss server, I notice that my class LoadBalance is being  initiated, but it is just in no time the application "enters" the methods  chooseTarget.

[wdfink]

First of all, if you use stateless session beans, it makes no sense to be sticky to one server because after the method call of SLSB all states are lost (e.g. entities or resources).

If you try to calculate with a second SLSB call all must be recalculated.

[tiagodfsouza]

Hum... I got it.

So, first should I change bean to Stateful?

[wdfink]

It depends to what you want ;-)

ok, better as example:

If you call more than one methods against one SessionBean, prepare something and then calculate according to what you have prepared.

It will be an idea to implement this as a stateful session bean, other is to transport the result to client and back or persist it in DB (or other).

For SFSB you need to know that it is not fail save in case of the note will crash. But I think it is not necessary in your case to replicate the session state, you can live with the failure in case of exact this node crash during the processing.

Also you do not need to implement your own load balancing, each call to the SFSB will reach the same server.

[tiagodfsouza]

Could make the redirection of URL's, but I use the mod_jk in Apache, to do load balancing among JBoss.

The configuration I did was to file worker.properties, and there arose a new  problem: "the user's session is lost."

My "worker.properties"

# Define list of workers that will be used for mapping requests
worker.list=status,relatorio,sistema

# TEMPLATE
worker.template.port=8009
worker.template.type=ajp13
worker.template.socket_timeout=0

# Define Node1
worker.nodeSis.reference=worker.template
worker.nodeSis.host=x.x.x.10

# Define Node2
worker.nodeRel.reference=worker.template
worker.nodeRel.host=x.x.x.20

# Load-balancing behaviour
worker.sistema.type=lb
worker.sistema.balance_workers=nodeSis
worker.sistema.sticky_session=1

# Status worker for managing load balancer
worker.status.type=status

# Relatorio behaviour
worker.relatorio.type=lb
worker.relatorio.balance_workers=nodeRel
worker.relatorio.sticky_session=1

[tiagodfsouza]

Just completing, redirection settings are on file mod_jk.conf.

Excerpt follows  below:

mod_jk.properties

(...)


# Mount your applications
JkMount /sistema                    sistema
JkMount /sistema/*                  sistema
JkMount /sistema/GeraRelatorio      relatorio

(...)