16.5.5. Configure Server Advertisement Properties for Your mod_cluster-enabled HTTPD

Summary

For instructions on configuring your HTTPD to interact with the mod_cluster load balancer, refer to Section 16.5.3, “Install the mod_cluster Module Into Apache HTTPD or JBoss Enterprise Web Server HTTPD (ZIP)”. One aspect of the configuration which needs more explanation is server advertisement.

When server advertisement is active, the HTTPD broadcasts messages containing the IP address and port number specified in the mod_cluster virtual host. To configure these values, refer to Section 16.5.3, “Install the mod_cluster Module Into Apache HTTPD or JBoss Enterprise Web Server HTTPD (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. Refer to Section 16.5.6, “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 HTTPD instance. This is often /etc/httpd/conf/httpd.conf in Red Hat Enterprise Linux, or may be in the etc/ directory of your stand-alone Apache HTTPD instance.

Procedure 16.6. 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 HTTPD server to receive MCPM messages from the worker nodes. 
    EnableMCPMReceive On

  4. Restart the HTTPD server.

    Restart the HTTPD 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
Result

The HTTPD 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. Refer to Section 16.5.6, “Configure a mod_cluster Worker Node” for more details.

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