Tomcat replication question

[Jeroen Meijer]

Hi Friends,

I'm trying to setup Tomcat context replication which 3 tomcat nodes and an Apache loadbalancer

I've changed context.xml on each Tomcat instance to

<Context distributable="true" className="org.apache.catalina.ha.context.ReplicatedContext" >

And added the <distributable/> tag to web.xml

I've written a context listener to test if the replication worked

package test;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class ContextListener implements ServletContextListener {

	public void contextDestroyed(ServletContextEvent sce) {
		ServletContext ctx = sce.getServletContext();
		ctx.setAttribute("storage", null);
		System.out.println("Context destroyed");
	}

	public void contextInitialized(ServletContextEvent sce) {
		System.out.println("Context init");
		ServletContext ctx = sce.getServletContext();
		if (ctx.getAttribute("storage") == null){
			System.out.println("init storage");
			ctx.setAttribute("storage", SharedStorage.getInstance());
		} else {
			System.out.println("storage was already set");
		}
		System.out.println("Context init end");
	}

}

When I look at the Tomcat logs it seems that replication is setup correctly

[Tomcat A]
INFO: Deploying web application directory ContextSharing
25-jan-2011 9:51:33 org.apache.catalina.ha.session.DeltaManager start
INFO: Register manager /ContextSharing to cluster element Engine with name Catal
ina
25-jan-2011 9:51:33 org.apache.catalina.ha.session.DeltaManager start
INFO: Starting clustering manager at /ContextSharing
25-jan-2011 9:51:33 org.apache.catalina.ha.session.DeltaManager getAllClusterSes
sions
INFO: Manager [localhost#/ContextSharing]: skipping state transfer. No members a
ctive in cluster group. -> First tomcat to start, so no members exists
Context init -> Initial context startup, this is okay
init storage
SharedStorage init
Context init end


Everything seems okay

[Tomcat B]
INFO: Starting clustering manager at /ContextSharing
25-jan-2011 9:52:25 org.apache.catalina.ha.session.DeltaManager getAllClusterSes
sions
WARNING: Manager [localhost#/ContextSharing], requesting session state from org.
apache.catalina.tribes.membership.MemberImpl[tcp://{192, 168, 1, 113}:4000,{192,
168, 1, 113},4000, alive=54015,id={-72 113 40 -25 -51 -71 73 -49 -120 -108 47 8
6 82 -9 53 -17 }, payload={}, command={}, domain={}, ]. This operation will time
out if no session state has been received within 60 seconds.
25-jan-2011 9:52:25 org.apache.catalina.ha.session.DeltaManager waitForSendAllSe
ssions
INFO: Manager [localhost#/ContextSharing]; session state send at 25-1-11 9:52 re
ceived in 109 ms.
Context init
init storage -> What's this?! This should have been done already by Tomcat A
SharedStorage init
Context init end

[Jeroen Meijer]

What am I missing?

[Tim Holloway]

Are you sure that's a problem? If I have 3 program using shared storage and I'm not meticulous about my wording, I might use the work "init" to mean "setting up for and connecting to shared storage" as opposed to "setting up and formatting shared storage".

[Jeroen Meijer]

??
I'm sorry for my English as it is not my native language.

I solved the problem: I forgot to implement Serializable

[Georges Salameh]

I want to ask you which tomcat version are you using? and what exactly was the error? i know that it was serializable but where it needs to be added?