19.5.5. Configure Server Advertisement Properties for Your mod_cluster-enabled Web Server


For instructions on configuring your web server to interact with the mod_cluster load balancer, see Section 19.5.3, “Install the mod_cluster Module Into Apache HTTP Server or JBoss Enterprise Web Server (Zip)”. One aspect of the configuration which needs more explanation is server advertisement.

When server advertisement is active, the web server broadcasts messages containing the IP address and port number specified in the mod_cluster virtual host. To configure these values, see Section 19.5.3, “Install the mod_cluster Module Into Apache HTTP Server or JBoss Enterprise Web Server (Zip)”. If UDP multicast is not available on your network, or you prefer to configure worker nodes with a static list of proxy servers, you can disable server advertisement and manually configure the worker nodes. See Section 19.5.6, “Configure a mod_cluster Worker Node” for information on configuring a worker node.
The changes in this procedure need to be made to the httpd.conf associated with your Apache HTTP Server instance. This is often /etc/httpd/conf/httpd.conf in Red Hat Enterprise Linux, or may be in the etc/ directory of your standalone Apache HTTP Server instance.

Procedure 19.8. Edit the httpd.conf file and implement the changes

  1. Disable the AdvertiseFrequency parameter, if it exists.

    If you have a line like the following in your <VirtualHost> statement, comment it out by putting a # (hash) character before the first character. The value may be different from 5.
    AdvertiseFrequency 5
  2. Add the directive to disable server advertisement.

    Add the following directive inside the <VirtualHost> statement, to disable server advertisement.
    ServerAdvertise Off
  3. Enable the ability to receive MCPM messages.

    Add the following directive to allow the Web server to receive MCPM messages from the worker nodes.
    EnableMCPMReceive On
  4. Restart the Web server.

    Restart the Web server by issuing one of the following, depending on whether you use Red Hat Enterprise Linux or Microsoft Windows Server.
    • Red Hat Enterprise Linux

      [root@host ]# service httpd restart
    • Microsoft Windows Server

      C:\> net service http
      C:\> net service httpd start

The web server no longer advertises the IP address and port of your mod_cluster proxy. To reiterate, you need to configure your worker nodes to use a static address and port to communicate with the proxy. See Section 19.5.6, “Configure a mod_cluster Worker Node” for more details.