On a production Linux server, we are experiencing a very strange phenomenon. Starting JBoss from the command prompt using 'run' loads the Coyote module properly - the log shows:
2007-11-19 09:01:49,893 INFO [org.apache.coyote.http11.Http11Protocol] Starting Coyote HTTP/1.1 on http-0.0.0.0-8080
2007-11-19 09:01:50,139 INFO [org.apache.jk.common.ChannelSocket] JK2: ajp13 listening on /0.0.0.0:8009
2007-11-19 09:01:50,144 INFO [org.apache.jk.server.JkMain] Jk running ID=0 time=0/123 config=null
However, loading it from the /etc/init.d/jboss_init.sh startup script does NOT load the module. JBoss starts up and all looks o.k. but now have the 503 errors between Apache and JBoss. This change in behavior occurred during our last shutdown/startup cycle.
I am desperate for an answer/solution.
The problem turned out to be the -Xmx JVM parameter - we upgraded the memory and then bumped this value up to 1700m. Apparently, if it is too high JBoss will load but not the AJP listener.