Troubleshooting mod_cluster
It is not working what should I do: Most likely you have a configuration problem. Check the log of the cluster nodes and error_log of httpd. 16.4.1. No error That happens when Advertise is not working: The nodes don't get the advertise messages from httpd. Check the modules are loaded and Advertise is started. In httpd.conf activate extended information display, add: AllowDisplay On When accessing to the mod_cluster_manager you should get something like: If not, go to the Minimal Example and add the missing directive(s). Check that Advertise message are received on the cluster node. A small Java utility could be used to check Advertise. It is in the mod_cluster repository and can be compiled using javac. A compiled version can be found under in /opt/jboss/httpd/tools in the bundles. Run it using java Advertise multicastaddress port. The output should be something like: [jfclere@jfcpc java]$ java Advertize 224.0.1.105 23364 ready waiting... received: HTTP/1.0 200 OK Date: Mon, 28 Jun 2010 07:30:31 GMT Sequence: 1 Digest: df8a4321fa99e5098174634f2fe2f87c Server: 1403c3be-837a-4e76-85b1-9dfe5ddb4378 X-Manager-Address: test.example.com:6666 X-Manager-Url: /1403c3be-837a-4e76-85b1-9dfe5ddb4378 X-Manager-Protocol: http X-Manager-Host: test.example.com No Advertise messages Check firewall (don't forget the boxes firewall). Advertise uses UDP port 23364 and multicast addresse 224.0.1.105 Can't get Advertise messages Use ProxyList property. In case Advertise can't work you put the address and port of the VirtualHost used in httpd to receive the MCMP. In server/profile/deploy/mod_cluster.sar/META-INF/mod_cluster-jboss-beans.xml test.example.com:6666 or in server.xml: 16.4.2. Error in server.log or catalina.out "IO error sending command ": Check firewall and error_log if there is nothing error_log then it is a firewall problem. If you have something like: 18:36:14,533 INFO [DefaultMCMPHandler] IO error sending command INFO to proxy jfcpc/10.33.144.3:8888 You can use telnet hostname/address port to check by hands that it is OK for example: [jfclere@jfcpc docs]$ telnet 10.33.144.3 8888 Trying 10.33.144.3... Connected to jfcpc. Escape character is '^]'. GET / It works!Connection closed by foreign host. Check that the address and port are the expected ones you may use ServerAdvertise On http://hostname:port, like: ServerAdvertise On http://localhost:6666 Or use the servlet testhttpd in the testhttpd.war of the bundle (in /opt/jboss/httpd/tools). Install/deploy it in in the node and start the AS/Tomcat on the node, than access to the node directly and call /testhttpd/testhttpd If you don't get a similar page the output should help to find that is wrong. 16.4.3. Error in error_log "client denied by server configuration": The directory in the VirtualHost is not allowed for the client. If you have something like: Mon Jun 28 18:08:47 2010] [error] [client 10.33.144.3] client denied by server configuration: / You need to have something like: Order deny,allow Deny from all Allow from 10.33.144.3