19.4.3. Disable Advertising for the mod_cluster Subsystem
By default, the
mod_cluster
subsystem's balancer uses multicast UDP to advertise its availability to the background workers. If you wish, you can disable advertisement. Use the following procedure to configure this behavior.
Procedure 19.6.
Modify the httpd configuration.
Modify the httpd configuration to disable server advertising and to use a proxy list instead. The proxy list is configured on the worker, and contains all of themod_cluster
-enabled Web servers the worker can talk to.Themod_cluster
configuration for the Web server is typically located in/etc/httpd/
or theetc/httpd/
directory within the httpd installation, if it is installed in a non-standard location. Refer to Section 19.5.3, “Install the mod_cluster Module Into Apache HTTP Server or JBoss Enterprise Web Server (Zip)” and Section 19.5.5, “Configure Server Advertisement Properties for Your mod_cluster-enabled Web Server” for more information about the file itself. Open the file containing the virtual host which listens for MCPM requests (using theEnableMCPMReceive
directive), and disable server advertising by changing theServerAdvertise
directive as follows.ServerAdvertise Off
Disable advertising within the
mod_cluster
subsystem of JBoss EAP 6, and provide a list of proxies.You can disable advertising for themod_cluster
subsystem and provide a list of proxies, by using the web-based Management Console or the command-line Management CLI. The list of proxies is necessary because themod_cluster
subsystem will not be able to automatically discover proxies if advertising is disabled.Management Console
If you use a managed domain, you can only configuremod_cluster
in profiles where it is enabled, such as theha
andfull-ha
profiles.- Log in to the Management Console and select the Configuration tab at the top of the screen. If you use a managed domain, select either the
ha
orfull-ha
profile from the Profile drop-down menu at the top left. - Expand the Subsystems menu then expand the Web menu and select mod_cluster.
- Click Edit under the Advertising tab under
mod_cluster
. To disable advertising, clear the check box next to Advertise, and click Save.Figure 19.1.
mod_cluster
Advertising Configuration Screen - Click the Proxies tab. Click Edit and enter a list of proxy servers in the Proxy List field. The correct syntax is a comma-separated list of
HOSTNAME:PORT
strings, like the following:10.33.144.3:6666,10.33.144.1:6666
Click the Save button to finish.
Management CLI
The following two Management CLI commands create the same configuration as the Management Console instructions above. They assume that you run a managed domain and that your server group uses thefull-ha
profile. If you use a different profile, change its name in the commands. If you use a standalone server using thestandalone-ha
profile, remove the/profile=full-ha
portion of the commands./profile=full-ha/subsystem=modcluster/mod-cluster-config=configuration/:write-attribute(name=advertise,value=false) /profile=full-ha/subsystem=modcluster/mod-cluster-config=configuration/:write-attribute(name=proxy-list,value="10.33.144.3:6666,10.33.144.1:6666")
Result
The httpd balancer no longer advertises its presence to worker nodes and UDP multicast is no longer used.