Clustering of tomcat servers

I am here with brief notes on how to form a clustering on tomcat servers.

1. Set up two tomcat servers (tomcat-pri & tomcat-sec)

2. In the setup of tomcat-pri, go the conf directory, and add following content in the server.xml file in the <Host> tag.

<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"

                 channelSendOptions="6">

          <Manager className="org.apache.catalina.ha.session.BackupManager"

                   expireSessionsOnShutdown="false"

                   notifyListenersOnReplication="true"

                   mapSendOptions="6"/>

          <Channel className="org.apache.catalina.tribes.group.GroupChannel">

            <Membership className="org.apache.catalina.tribes.membership.McastService"

                        address="228.0.0.4"

                        port="45564"

                        frequency="500"

                        dropTime="3000"/>

            <Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"

                      address="auto"

                      port="5000"

                      selectorTimeout="100"

                      maxThreads="6"/>

            <Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter">

              <Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender"/>

            </Sender>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatch15Interceptor"/>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.ThroughputInterceptor"/>

          </Channel>

          <Valve className="org.apache.catalina.ha.tcp.ReplicationValve"

                 filter=".*\.gif|.*\.js|.*\.jpeg|.*\.jpg|.*\.png|.*\.htm|.*\.html|.*\.css|.*\.txt"/>

          <Deployer className="org.apache.catalina.ha.deploy.FarmWarDeployer"

                    tempDir="/tmp/war-temp/"

                    deployDir="/host/Work/servers/tomcat-pri/webapps"

                    watchDir="/tmp/war-listen/"

                    watchEnabled="true"/>

          <ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener"/>

        </Cluster>

NOTE: If you observe carefully, the server.xml will have <Cluster> tag is commented out with in the <Engine> tag. However, we need to keep the <Cluster> tag with in the <Host> tag.

3. In the setup of tomcat-pri, go the conf directory, and edit the server.xml file.

Change the port information so that, you wouldn't see port already used messages in the logs.

(i) Server Port

(ii) Connector Port (two places)

4. Also add following content in the server.xml file of tomcat-sec setup.

<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"

                 channelSendOptions="6">

          <Manager className="org.apache.catalina.ha.session.BackupManager"

                   expireSessionsOnShutdown="false"

                   notifyListenersOnReplication="true"

                   mapSendOptions="6"/>

          <!--

          <Manager className="org.apache.catalina.ha.session.DeltaManager"

                   expireSessionsOnShutdown="false"

                   notifyListenersOnReplication="true"/>

          -->

          <Channel className="org.apache.catalina.tribes.group.GroupChannel">

            <Membership className="org.apache.catalina.tribes.membership.McastService"

                        address="228.0.0.4"

                        port="45564"

                        frequency="500"

                        dropTime="3000"/>

            <Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"

                      address="auto"

                      port="5020"

                      selectorTimeout="100"

                      maxThreads="6"/>

            <Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter">

              <Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender"/>

            </Sender>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatch15Interceptor"/>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.ThroughputInterceptor"/>

          </Channel>

          <Valve className="org.apache.catalina.ha.tcp.ReplicationValve"

                 filter=".*\.gif|.*\.js|.*\.jpeg|.*\.jpg|.*\.png|.*\.htm|.*\.html|.*\.css|.*\.txt"/>

          <Deployer className="org.apache.catalina.ha.deploy.FarmWarDeployer"

                    tempDir="/tmp/war-temp/"

                    deployDir="/host/Work/servers/apache-tomcat-7.0.41-sec/webapps"

                    watchDir="/tmp/war-listen/"

                    watchEnabled="true"/>

          <ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener"/>

        </Cluster>

5. Now, deploy the web-application artifact in the directory "/tmp/war-listen"

6. Start the tomcat-pri server

7. Start the tomcat-sec server (once tomcat-pri server is started)

8. You would observer following in logs.

Jun 17, 2013 1:53:11 PM org.apache.coyote.AbstractProtocol init

INFO: Initializing ProtocolHandler ["http-bio-8080"]

Jun 17, 2013 1:53:11 PM org.apachecatalina.startup.Catalina load

INFO: Initialization processed in 524 ms

Jun 17, 2013 1:53:11 PM org.apache..coyote.AbstractProtocol init

INFO: Initializing ProtocolHandler ["ajp-bio-8009"]

Jun 17, 2013 1:53:11 PM org.apache.catalina.core.StandardService startInternal

INFO: Starting service Catalina

Jun 17, 2013 1:53:11 PM org.apache.catalina.core.StandardEngine startInternal

INFO: Starting Servlet Engine: Apache Tomcat/7.0.41

Jun 17, 2013 1:53:11 PM org.apache.catalina.ha.tcp.SimpleTcpCluster startInternal

INFO: Cluster is about to start

Jun 17, 2013 1:53:11 PM org.apache.catalina.tribes.transport.ReceiverBase bind

INFO: Receiver Server Socket bound to:/127.0.1.1:5000

Jun 17, 2013 1:53:11 PM org.apache.catalina.tribes.membership.McastServiceImpl setupSocket

INFO: Setting cluster mcast soTimeout to 500

Jun 17, 2013 1:53:11 PM org.apache.catalina.tribes.membership.McastServiceImpl waitForMembers

INFO: Sleeping for 1000 milliseconds to establish cluster membership, start level:4

Jun 17, 2013 1:53:12 PM org.apache.catalina.tribes.membership.McastServiceImpl waitForMembers

INFO: Done sleeping, membership established, start level:4

Jun 17, 2013 1:53:12 PM org.apache.catalina.tribes.membership.McastServiceImpl waitForMembers

INFO: Sleeping for 1000 milliseconds to establish cluster membership, start level:8

Jun 17, 2013 1:53:13 PM org.apache.catalina.tribes.membership.McastServiceImpl waitForMembers

INFO: Done sleeping, membership established, start level:8

Jun 17, 2013 1:53:13 PM org.apache.catalina.ha.deploy.FarmWarDeployer start

INFO: Cluster deployment is watching [/tmp/war-listen/] for changes.

Jun 17, 2013 1:53:13 PM org.apache.catalina.ha.deploy.FarmWarDeployer start

INFO: Cluster FarmWarDeployer started.

Configuration of Jetty-Maven plugin to a web app

In present era development process, everybody is primarily concerned about faster development process, because of which development environment has become vital in the project implementation plan.

Jetty is the one of the light weight application server, which can be run on stand-alone or using maven plugin. I am here giving the configuration details of later one.

(One assumption here is, reader has the knowledge of Maven)

1. Add jetty-maven plugin in the plugins section of pom.xml


           <plugin>
                <groupId>org.mortbay.jetty</groupId>
                <artifactId>jetty-maven-plugin</artifactId>
                <version>8.1.9.v20130131</version>
                <configuration>
                    <connectors>
                        <connector  implementation="org.eclipse.jetty.server.nio.SelectChannelConnector">
                            <port>8080</port>
                        </connector>
                    </connectors>
                    <stopPort>18080</stopPort>
    <scanIntervalSeconds>0</scanIntervalSeconds>
    <webXml>target/classes/web.xml</webXml>
    <webApp>
           <contextPath>/</contextPath>
    </webApp>
                </configuration>
                <dependencies>
                    // any dependencies required can be added here
                    // if you project has dependency on jsf, add jsf dependencies here too.
                </dependencies>
            </plugin>


2. Go to the terminal and change directory to base directory of project and run the server using below command.

mvn jetty:run

PS: Maven Options might need to be mentioned

(i) Perm Genspace attributes:
MAVEN_OPTS="-Xmx1024m -XX:MaxPermSize=256m"

(ii) Starting jetty server in debug mode with Perm Genspace attributes:
MAVEN_OPTS="-Xmx1024m -XX:MaxPermSize=256m -Xdebug -Xnoagent -Djava.compiler=NONE -Xrunjdwp:transport=dt_socket,address=4000,server=y,suspend=y"