Apache Mod Cluster as load balancer (LB) - JBoss 6.4

Connector	Supports Sticky Sessions	Adapts to Deployment Status
mod_cluster	Yes	Yes. Detects deployment and undeployment of applications and dynamically decides whether to direct client requests to a server based on whether the application is deployed on that server.
mod_jk	Yes	No. Directs client requests to the container as long as the container is available, regardless of application status.
mod_proxy	Yes	No. Directs client requests to the container as long as the container is available, regardless of application status.
ISAPI connector	Yes	No. Directs client requests to the container as long as the container is available, regardless of application status.
NSAPI connector	Yes	No. Directs client requests to the container as long as the container is available, regardless of application status.

Advantages:

• ·         Workers register themselves with httpd servers.
• ·         NO more workers.properties
• ·         Changes in cluster topology are send to httpd.
• ·         Deployed applications are automatically register, which can be Disable, stop & Enable    from balancer HTTP console.
• ·         NO 404s for un-deployed applications.
• ·         Load balancer function automatically managed.

Software Details:

(1)  Apache/2.4.34(Unix) 

(2)  JBossEAP 6.4.0.GA (AS 7.5.0.Final-redhat-21) 

(3) Download  mod_clustermodules for httpd 

Step 1: Install Apache server on UNIX.

Use below link to install Apache server on UNIX step by step.

https://www.middlewarebox.com/2017/08/how-to-install-apache-http-server-2427.html

Step 2: Download “mod_cluster modules for httpd” from below link, as per your environment.

http://mod-cluster.jboss.org/mod_cluster/downloads/1-3-1-Final-bin

Screenshot: 

Screenshot: 

Step 3: Move this mod_cluster modules to installed Apache server modules location.  “$Apache_Home/modules”.

Step 4: Add below configuration to httpd.conf file at “$Apache_Home/conf”.

NOTE: Disable mod_proxy_balancer module.

# mod_proxy_balancer should be disabled while using mod_cluster.

***************************************************************

LoadModule proxy_module modules/mod_proxy.so

LoadModule proxy_ajp_module modules/mod_proxy_ajp.so

LoadModule proxy_cluster_module modules/mod_proxy_cluster.so

LoadModule cluster_slotmem_module modules/mod_cluster_slotmem.so

LoadModule manager_module modules/mod_manager.so

LoadModule advertise_module modules/mod_advertise.so

MemManagerFile /Apache/HTTPDWEB2.4/MemManagerFile

<IfModule manager_module>

Listen 10.142.0.2:9111

        ManagerBalancerName mycluster-1

        ManagerBalancerName mycluster-2

<VirtualHost 10.142.0.2:9111>

    <Directory />

##      AllowOverride None

      Require all granted

    </Directory>

    ServerAdvertise off

        EnableMCPMReceive

        KeepAliveTimeout 60

<Location /mod_cluster_manager>

    SetHandler mod_cluster-manager

      Require all granted

</Location>

</VirtualHost>

</IfModule>

AllowDisplay On

***************************************************************

Where,

MemManagerFile: That is the base name for the names mod_manager will use to store configuration, generate keys for shared memory or lock files. That must be an absolute path name; the directories will created if needed. It is highly recommended that those files are placed on a local drive and not an NFS share.

Default: $Apache_Home/logs/.

ServerAdvertise On: Use the advertise mechanism to tell the JBoss AS to whom it should send the cluster information.

ServerAdvertise On http://hostname:port: Tell the hostname and port to use. Only needed if the VirtualHost is not defined correctly, if the VirtualHost is a Name-based Virtual Host [http:// httpd.apache.org/docs/2.2/vhosts/name-based.html] or when VirtualHost is not used.

ServerAdvertise Off: Don't use the advertise mechanism.

EnableMCPMReceive - Allow the VirtualHost to receive the MCPM from the nodes. You need one EnableMCPMReceive in your httpd configuration to allow mod_cluster to work, put it in the VirtualHost where you configure advertise.

SetHandler mod_cluster-manager: That is the handler to display the node mod_cluster sees from the cluster. It displays the information about the nodes like INFO and additionally counts the number of active sessions.

NOTE:

On httpd 2.2

#########

Order allow,deny

Allow from all

#########

And On   httpd 2.4 we use,

#########

Require all granted

#########

We have done with mod_cluster configuration on Apache Server.

Screenshot:

 Screenshot:

Step 5:  For performing  mod_cluster method, we need to use standalone-ha.xml or standalone-full-ha.xml profile, Since this ha & full-ha has a mod_cluster subsystem configuration.

We will use ha profile.

Step 6: Add Jboss Server name on “standalone-ha.xml”.

**********************************************

<?xml version='1.0' encoding='UTF-8'?>

<server name="jboss-eap-6.4-1"   xmlns="urn:jboss:domain:1.7">

    <extensions>

**********************************************

Screenshot:

Step 7: Add Proxy-list and  Balancer name to “standalone-ha.xml” mod cluster subsystem.

***************************

        <subsystem xmlns="urn:jboss:domain:modcluster:1.2">

            <mod-cluster-config proxy-list="10.142.0.2:9111"  advertise-socket="modcluster" connector="ajp" balancer="mycluster-1" >

                <dynamic-load-provider>

                    <load-metric type="busyness"/>

                </dynamic-load-provider>

            </mod-cluster-config>

        </subsystem>

***************************

 Screenshot:

Step 8: Add Node name to “standalone-ha.xml” web subsystem.

  ***************************

     <subsystem xmlns="urn:jboss:domain:web:2.2" default-virtual-server="default-host" native="false" instance-id="jboss-eap-Node-1" >

            <connector name="http" protocol="HTTP/1.1" scheme="http" socket-binding="http"/>

            <connector name="ajp" protocol="AJP/1.3" scheme="http" socket-binding="ajp"/>

            <virtual-server name="default-host" enable-welcome-root="true">

                <alias name="localhost"/>

                <alias name="example.com"/>

            </virtual-server>

        </subsystem>

***************************

Screenshot:

 Step 9: Start the “JBoss instance-1” from “$JBOSS_HOME-1/bin”, using below script,

./standalone.sh  -c  standalone-ha.xml   -b  10.142.0.2  -bmanagement  10.142.0.2

 Screenshot:

Step 10: Now, perform same configuration changes using different server name, balancer name & instance-id on “JBoss instance-2”.

NOTE:  use port offset for socket-binding on “standalone-ha.xml”.

**********************************

  <socket-binding-group name="standard-sockets" default-interface="public" port-offset="${jboss.socket.binding.port-offset:10}">

**********************************

Step 11: Start the “JBoss instance-2” from  “$JBOSS_HOME-2/bin”, using below script.

./standalone.sh  -c  standalone-ha.xml   -b  10.142.0.2  -bmanagement  10.142.0.2

Screenshot:

Step 12: Check through browser, using http://ip:PORT/mod_cluster_manager

http://35.231.89.125:9111/mod_cluster_manager

 Screenshot:

Step 13: check the applications.

http://35.231.89.125/Sample/

http://35.231.89.125/Calendar/

http://35.231.89.125/Hello/

 Screenshot:

Reference links:

• http://docs.jboss.org/mod_cluster/1.3.0/pdf/Mod_cluster-UserGuide.pdf 
• https://docs.jboss.org/author/display/AS71/Setting+multiple+mod_cluster+load+balancers+in+clustering+environment
• https://docs.jboss.org/mod_cluster/1.2.0/html/
• http://mod-cluster.jboss.org/mod_cluster/downloads/1-3-1-Final-bin

Thanks :-)