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Target Audience

Cluster Configuration

Group Configuration

Web Container

EJB Container

Disabling L1 cache for distributed cache:

Load Balancing & Failover

Apache Httpd

The recommended front-end module is mod_cluster but mod_jk or mod_proxy could be used as in Tomcat or other AS version.

To use AJP define a ajp connector in the web subsystem like:

<subsystem xmlns="urn:jboss:domain:web:1.0">
            <connector name="http" protocol="HTTP/1.1" socket-binding="http"/>
            <connector name="ajp" protocol="AJP/1.3" socket-binding="ajp"/>

Note: Don't use scheme="ajp" wiith ajp connectors because scheme is used for the redirects

To the ajp in the in the socket-binding-group like:

<socket-binding-group name="standard-sockets" default-interface="public">
           <socket-binding name="http" port="8080"/>
           <socket-binding name="ajp" port="8009"/>
           <socket-binding name="https" port="8443"/>

Mod Cluster

The mod_cluster integration is done via the modcluster subsystem it requires mod_cluster-1.1.x.

The modcluster subsystem supports several operations:

The operations specific to the modcluster subsystem are divided in 3 categories the ones that affects the configuration and require a restart of the subsystem, the one that just modify the behaviour temporarily and the ones that display information from the httpd part.

operations displaying httpd informations

There are 2 operations that display how Apache httpd sees the node:


Send a DUMP message to all Apache httpd the node is connected to and display the message received from Apache httpd.


Send a INFO message to all Apache httpd the node is connected to and display the message received from Apache httpd.

operations that handle the proxies the node is connected too

there are 3 operation that could be used to manipulate the list of Apache httpd the node is connected too.


Displays the httpd that are connected to the node. The httpd could be discovered via the Advertise protocol or via the proxy-list attribute.


Remove a proxy from the discovered proxies or  temporarily from the proxy-list attribute.


Add a proxy to the discovered proxies or  temporarily to the proxy-list attribute.

Context related operations

Those operations allow to send context related commands to Apache httpd. They are send automatically when deploying or undeploying  webapps.


"Tell Apache httpd that the context is ready receive requests.


Tell Apache httpd that it shouldn't send new session requests to the context of the virtualhost.


Tell Apache httpd that it shouldn't send requests to the context of the virtualhost.

Node related operations

Those operations are like the context operation but they apply to all webapps running on the node and operation that affect the whole node.


Refresh the node by sending a new CONFIG message to Apache httpd.


reset the connection between Apache httpd and the node


Metric configuration

There are 4 metric operations corresponding to add and remove load metrics to the dynamic-load-provider.

Note that when nothing is defined a simple-load-provider is use with a fixed load factor of one.

that corresponds to the following configuration:

When using the dynamic-load-provider it is possible to have a list of metric and custom-metric to collect information for the web-app, web server, the JVM etc. There are 2 lists one containing the metrics the other containing the custom-metric. custom-metrics are normally customer written metrics.

The standard metrics are the following ones:

Server-Side Load Metric description
AverageSystemLoadMetric Returns CPU load
SystemMemoryUsageLoadMetric Returns system memory usage
heap HeapMemoryUsageLoadMetric Returns the heap memory usage as a percentage of max heap size
sessions ActiveSessionsLoadMetric Returns the percentage of busyness based on the number of active sessions needs a property:  capacity.
requests RequestCountLoadMetric Returns the percentage of connector threads from the thread pool that are busy servicing requests
send-traffic SendTrafficLoadMetric Returns the percentage of busyness based onthe outgoing request traffic in KB/sec.needs a property: capacity.
receive-traffic ReceiveTrafficLoadMetric Returns the percentage of busyness based on the incoming request POST traffic in KB/sec (the application needs to read POST data).needs a property: capacity.
busyness BusyConnectorsLoadMetric Returns the percentage of connector threads from the thread pool that are busy servicing requests
connection-pool ConnectionPoolUsageLoadMetric Returns the percentage of connections from a connection pool that are in use. (needs properties). (NOT SUPPORTED)

Add a metric to the dynamic-load-provider, the dynamic-load-provider in configuration is created if needed.

When properties are needed it is possible to add them using the standard format like:

For example:


Remove a metric from the dynamic-load-provider.

add-custom-metric / remove-custom-metric

like the add-metric and remove-metric except they require a class parameter instead the type. Usually they needed additional properties which can be specified

which corresponds the following in the xml configuration file:

JVMRoute configuration

If you want to use your own JVM route instead of automatically generated one you can insert the following property:

SSL configuration:

If you want to use SSL between AS7 and httpd, which is to get  the node behaves like client browser for httpd, you have to configure the httpd side see mod_ssl documentation.

To configure SSL you have to create the ssl configuration and then change the attributes you need to configure, for example:



All JBoss AS 7 documentation

There are several guides in the JBoss Application Server 7 documentation series. This list gives an overview of each of the guides:

*Getting Started Guide - Explains how to download and start JBoss Application Server 7.
*Getting Started Developing Applications Guide - Talks you through developing your first applications on JBoss Application Server 7, and introduces you to JBoss Tools and how to deploy your applications.
*JavaEE 6 Tutorial - A Java EE 6 Tutorial.
*Admin Guide - Tells you how to configure and manage your JBoss Application Server 7 instances.
*Developer Guide - Contains concepts that you need to be aware of when developing applications for JBoss Application Server 7. Classloading is explained in depth.
*High Availability Guide - Reference guide for how to set up clustered JBoss Application Server 7 instances.
*Extending JBoss AS 7 - A guide to adding new functionality to JBoss Application Server 7.

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  1. Jun 18, 2012

    How can i perform Load Balancing and failover with JBoss AS7.