Configuring the Tomcat Connector for a JBoss AS cluster

In a multiple-node JBoss Application Server (JBoss AS) environment, you can configure the web server to act as the load balancer server that redirects requests to the separate nodes.

For this configuration, first ensure that the node names for each of the JBoss AS instances in your cluster are defined correctly. Then edit the .properties files in the mod_jk/conf directory to define the Tomcat instance (also known as a Tomcat worker) for each JBoss AS instance in the cluster.

Note: The following are examples of .properties files used to configure a typical multiple-node JBoss AS deployment. Analyze your configuration and adjust these settings accordingly.

To configure the Tomcat Connector for a multiple-node JBoss AS deployment:

  1. Verify that the server.xml file for each of the JBoss servers in your cluster specifies a unique node name.
    The server.xml file for a given node is located in the JBOSS_HOME\server\nodename\deploy\jbossweb.sar directory. The node name is specified by the jvmRoute attribute in the Engine tag. For example:
    <Engine defaultHost="localhost" jvmRoute="node1"
    name="jboss.web">

    Typically, the node names are configured when you set up the server. This happens automatically if, when you are deploying, you specify the Configure Automatically or Configure Server options in NexJ Studio.

  2. Edit the uriworkermap.properties file to define the nodes for your deployment.
    For example: 
    /nexj/*=loadbalancer
  3. Edit the workers.properties file to configure the nodes and their properties.
    For example:
    
# The list of nodes 
# 
worker.list=loadbalancer,status

# Set load-balancing behaviour 
# 
worker.loadbalancer.type=lb
worker.loadbalancer.balance_workers=node1,node2
worker.loadbalancer.sticky_session=1 

# Set template properties 
#
worker.template.type=ajp13
worker.template.lbfactor=1 
worker.template.socket_timeout=0
worker.template.socket_keepalive=true
worker.template.socket_connect_timeout=5000
worker.template.retries=2 
worker.template.recovery_options=7
worker.template.connection_pool_size=256
worker.template.connection_pool_timeout=300 

# Set properties for node 1 
# 
worker.node1.reference=template
worker.node1.host=localhost 
worker.node1.port=8009
worker.node1.route=node1 

# Set properties for node 2 
# 
worker.node2.reference=template
worker.node2.host=localhost 
worker.node2.port=8109
worker.node2.route=node2 

# Set properties for status worker 
# 
worker.status.type=status
worker.status.read_only=true

    The values for the worker.nodename.host and worker.nodename.port properties must correspond to your JBoss AS configuration. If you add or remove any workers, change the worker.loadbalancer.balance_workers property.

    Node names such as "node1" or "node2" are used by default when the servers are configured through NexJ Studio. If you specify different names in the server.xml file, use the worker.nodename.route property to map the node names and worker names correctly.

    By default, the value of the worker.nodename.route property is set to the worker name. If that is the case, you do not have to include this property. In a typical production environment, only one cluster is configured for each mod_jk module, so this property is not required.

    In the configuration, the following suggested values are used:
    worker.nodename.type
    The value is always ajp13. Other worker types are unsupported.
    worker.nodename.retries
    Suggested value is 2. The maximum number of times that the node will try to establish a connection to the server after a communication error.
    worker.nodename.recovery_options

    Suggested value is 7. This value is a bitmask. It indicates that, when an error occurs that prevents a complete AJP request from being sent, the server will not retry the request and will close the AJP connection. This prevents automatic request and response duplication.

    worker.nodename.connection_pool_size

    Suggested value is 256. The lower of the maximum Tomcat/JBoss AJP listener thread count and the maximum web server thread count.

    To determine the maximum Tomcat/JBoss AJP listener thread count: In the deploy/jbossweb.sar/server.xml file, refer to the maxThreads attribute for the Connector component for AJP.

    To determine the maximum web server thread count: Refer to Apache or IIS configuration to find the maximum number of web requests that the server can process concurrently.

    worker.nodename.connection_pool_timeout
    Suggested value is 300. The number of seconds after which the idle connections in the pool are closed.
    worker.nodename.socket_keepalive
    Suggested value is true. Sends TCP keepalive messages to maintain the connection.
    worker.nodename.socket_timeout
    Suggested value is 0. Indicates that IIS should wait for the server response indefinitely.
    worker.nodename.socket_connect_timeout
    Suggested value is 5000. The number of milliseconds after which the attempted connection establishment times out.
    Note: Refer to the Apache Tomcat documentation for the list and description of all configurable worker properties: http://tomcat.apache.org/connectors-doc/reference/workers.html.
  4. If you are configuring an existing web server that is currently running, restart the web server after modifying the configuration files.