JBoss 7.1.1.Final clustering with mod_proxy and Apache 2.2

This article shows how to configure a cluster made up of two JBoss AS 7.1.1.Final instances and how to config Apache Web Server to implement the so-called load balanced mechanism.

The version of Apache used to implement this example is Apache 2.2

Firstly, I would like to show how to create two clustered nodes with JBoss standalone version.

Finally, I will outline the steps needed to configure the Apache server to behave just like a load balancer element.

JBoss Cluster configuration

It is extremely easy to create a JBoss cluster based on the Standalone modality.

Imagine that the Jboss server is installed in the following filesystem location.

\JBOSS_HOME\

For dealing with a simple and non-infrastructure complex example, this example deploy two clustered nodes in the same machine but listening different ports.

Thus, we are going to create two nodes called: node1 and node 2

For creating each node, the following steps must be followed:

1) Copy the folder \JBOSS_HOME\standalone to \JBOSS_HOME\ with the name, for instance, “standalone_node1”

2) Copy the folder \JBOSS_HOME\standalone again to \JBOSS_HOME\ with the name, form instance, “standalone_node2”

3) In the \JBOSS_HOME\bin create a “bat” file called, for instance, “cluster_node1.bat” and include the following sentence that run and deploy the instance of the node1.

./standalone.bat -c standalone-ha.xml -b 127.0.0.1 -u 230.0.0.4 -Djboss.server.base.dir=../standalone_node1 -Djboss.node.name=node1 -Djboss.socket.binding.port-offset=100

 4) In the \JBOSS_HOME\bin create a “bat” file called, for instance, “cluster_node2.bat” and include the following sentence that run and deploy the instance of the node1.

./standalone.bat -c standalone-ha.xml -b 127.0.0.1 -u 230.0.0.4 -Djboss.server.base.dir=../standalone_node2 -Djboss.node.name=node2 -Djboss.socket.binding.port-offset=200

5) Finally, execute in different cmd console each of the “bat” files in order to lauch and make available the JBoss cluster.

APACHE LOAD BALANCER CONFIGURATION

For activate the load balancer feature of the Apache, I assume in this example to do so by using the mod_proxy module that is included in this version of Apache Web Server. It is not the best option to configure a load balancer node, because the best protocol called ajp is not used. Instead, all the communication is based on the common http protocol.

In the file \APACHE_HOME\conf\httpd.conf several modifications must be done:

1) Activate the following modules by adding these sentences

LoadModule proxy_module modules/mod_proxy.so

LoadModule proxy_ajp_module modules/mod_proxy_ajp.so

LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

LoadModule proxy_connect_module modules/mod_proxy_connect.so

LoadModule proxy_ftp_module modules/mod_proxy_ftp.so

LoadModule proxy_http_module modules/mod_proxy_http.so

LoadModule proxy_scgi_module modules/mod_proxy_scgi.so

Be aware that all this *.so files are included in the distributable 2.2.* version of Apache

2) Create a virtual host as follow:

<VirtualHost localhost:90>

    ServerName localhost:90

    DocumentRoot "d:/Program Files/Apache Software Foundation/Apache2.2/htdocs"

    # Enable forward proxy

    ProxyRequests On

    ProxyVia On

    <Proxy *>

        Order deny,allow

        Allow from all

    </Proxy>

    # Enable reverse proxy

    ProxyPass / balancer://mycluster/ stickysession=JSESSIONID

    ProxyPassReverse / http://localhost:8180/

    ProxyPassReverse / http://localhost:8280/

    <Proxy balancer://mycluster>

        BalancerMember http://localhost:8180/ route=node1

        BalancerMember http://localhost:8280/ route=node2

        # Set counting algorithm to more evenly distribute work:

        ProxySet lbmethod=byrequests

    </Proxy>

    # Enable load balancer management

    <Location /balancer-manager>

        SetHandler balancer-manager

    </Location>

    <Directory "htdocs">

        AllowOverride AuthConfig

    </Directory>

</VirtualHost>

As you can see, this load balancer configuration points to the two JBoss instances deployed by way of the http ports (8180 for node 1 and 8280 for node2).

 The Jboss node1 listen the request in the port 8180 because when the instance is launched , the port offset is indicated properly in the command showed previously (8080 + 100 offset=8180). The same for the node 2 (8080 + 200=8280).

./standalone.bat -c standalone-ha.xml -b 127.0.0.1 -u 230.0.0.4 -Djboss.server.base.dir=../standalone_node1 -Djboss.node.name=node1 -Djboss.socket.binding.port-offset=100

./standalone.bat -c standalone-ha.xml -b 127.0.0.1 -u 230.0.0.4 -Djboss.server.base.dir=../standalone_node2 -Djboss.node.name=node2 -Djboss.socket.binding.port-offset=200

With these steps, you have in your own machine a Jboss cluster comprised of two nodes and in front of them an Apache Web service balancing the petitions.