Clustering with JBoss AS: Simple test

2012-12-13

Clustering with JBoss AS: Simple test

1) Have two servers:

cp jbossas/server/all jbossas/server/all2`

2) Start both servers

# Server 1
bin/run.sh -u 224.13.15.5 -c all  -b 0.0.0.0 -Djboss.messaging.ServerPeerID=1
# Server 2
bin/run.sh -u 224.13.15.5 -c all2 -b 0.0.0.0 -Djboss.messaging.ServerPeerID=2

-Djboss.messaging.ServerPeerID=1 is there to set the cluster node ID for messaging & JGroups, being used in jbossas/server/<profile>/deploy/messaging/messaging-service.xml:

<server>

   <!-- ServerPeer MBean configuration
        ============================== -->

   <mbean code="org.jboss.jms.server.ServerPeer"
      name="jboss.messaging:service=ServerPeer"
      xmbean-dd="xmdesc/ServerPeer-xmbean.xml">

      <!-- The unique id of the server peer - in a cluster each node MUST have a unique value - must be an integer -->
      <attribute name="ServerPeerID">${jboss.messaging.ServerPeerID:0}</attribute>
      ...
   </mbean>
</server>

If you don't set it, you'll see:

2009-05-02 19:58:56,116 DEBUG [org.jboss.messaging.core.jmx.MessagingPostOfficeService] Starting failed jboss.messaging:service=PostOffice
java.lang.IllegalArgumentException: Cannot start post office since there is already a post office in the cluster with the same node id (0).
Are you sure you have given each node a unique node id during installation?

5) Then create an application which sets some session data.

app.war/WEB-INF/web.xml:

<?xml version="1.0"?>
<web-app  xmlns="http://java.sun.com/xml/ns/j2ee"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
          version="2.4">
  <distributable/>
</web-app>

app.war/index.jsp: (Sorry for the poor JSP code :)

<html>
  <body>
<%
        String host;
        try {
        java.net.InetAddress localMachine = java.net.InetAddress.getLocalHost();
        host = localMachine.getHostName();
        }
        catch( java.net.UnknownHostException ex ) {
        host = ex.getMessage();
        }
%>
        <b>Session ID: </b><%= session.getId() %><br>
   <b>Hostname: </b><%= host %><br>

   <pre>
     Current name in session:  <%= session.getAttribute( "theName" ) %>
<%
   String name = request.getParameter( "username" );
   session.setAttribute( "theName", name );
%>
      Setting name in session:  <%= name %>
   </pre>

  </body>
</html>

6) Copy the app.war to both profiles to app/deploy and app2/deploy.

Server 1:

06:16:46,246 INFO  [PlatformMBeanServerRegistration] JBossCache MBeans were successfully registered to the platform mbean server.
06:16:46,527 INFO  [STDOUT]
---------------------------------------------------------
GMS: address is 10.34.33.46:38534 (cluster=DefaultPartition-SessionCache)
---------------------------------------------------------
06:16:48,563 INFO  [RPCManagerImpl] Received new cluster view: [10.34.33.46:38534|0] [10.34.33.46:38534]
06:16:48,579 INFO  [RPCManagerImpl] Cache local address is 10.34.33.46:38534
06:16:48,582 INFO  [RPCManagerImpl] state was retrieved successfully (in 2.05 seconds)
06:16:48,612 INFO  [ComponentRegistry] JBoss Cache version: JBossCache 'Malagueta' 3.2.1.GA
06:18:29,503 INFO  [RPCManagerImpl] Received new cluster view: [10.34.33.46:38534|1] [10.34.33.46:38534, 10.34.33.50:42679]

Server 2: (Note the LegacyStateTransferIntegrator.)

06:18:28,968 INFO  [TomcatDeployment] deploy, ctxPath=/app
06:18:29,283 INFO  [PlatformMBeanServerRegistration] JBossCache MBeans were successfully registered to the platform mbean server.
06:18:29,319 INFO  [STDOUT]
---------------------------------------------------------
GMS: address is 10.34.33.50:42679 (cluster=DefaultPartition-SessionCache)
---------------------------------------------------------
06:18:29,508 INFO  [RPCManagerImpl] Received new cluster view: [10.34.33.46:38534|1] [10.34.33.46:38534, 10.34.33.50:42679]
06:18:29,557 INFO  [LegacyStateTransferIntegrator] Using version 4096
06:18:29,578 INFO  [RPCManagerImpl] Cache local address is 10.34.33.50:42679
06:18:29,578 INFO  [RPCManagerImpl] state was retrieved successfully (in 260 milliseconds)
06:18:29,593 INFO  [ComponentRegistry] JBoss Cache version: JBossCache 'Malagueta' 3.2.1.GA

7) „Load balancing“

Now you have to use the same session ID for both servers. Your browser will consider the servers as distinct and use different cookie for each. So you can either use the jsessionid=... or set up some hi-tech load-balancing:

ssh -D 9090 -Nf jawa15.englab.brq.redhat.com

# Or, if your server is at :8080 as is by default:

ssh -f ozizka@jawa15.englab.brq.redhat.com -L 9091:jawa15.englab.brq.redhat.com:8080 -N

8) Check if the session data replicates

Go to http://localhost:9091/app/?username=OndraZizka.

Then switch the proxy to the other server:

ps aux | grep 'L 9091:jawa17'
 ...
kill 1234
ssh -f ozizka@jawa17.englab.brq.redhat.com -L 9091:jawa17.englab.brq.redhat.com:8080 -N

Then again go to http://localhost:9091/app/?username=EdWoods.

You should see that the original user name „OndraZizka“ was replicated to the other server.

That's it :)

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