Installation guide

If this does not resolve the issue, proceed to St ep 2
b. Confirm that there is no firewall blocking or dropping the AJP connections.
General Performance Issues
Presents with errors like the following:
ERROR [org.apache.coyote.ajp.AjpMessage] (ajp-192.168.0.101-8001-13)
Invalid message received with signature 12336
The above exception when using mod_jk in JBoss Web typically indicates a non AJP request
sent to the AJP connector.
Workflows that may assist in resolving these kinds of issues is below:
Procedure 4.3. General Performance Problems
1. Optimize your Apache and JBoss configuration. You can contact Red Hat's Global
Support Services for assistance with this.
If this does not resolve the issue, proceed to St ep 2
2. Gather garbage collection logs for analysis.
If the logs show long garbage collection pause times then you should optimize the Java
Virtual Machine to reduce the garbage collection pauses and gather/recheck updated
logs. Refer to https://access.redhat.com/knowledge/solutions/19932 (Red Hat account
required) for more information.
If this is not the case, or did not resolve the issue, try Step 3, Step 4 and/or Step 5 until
your issue is resolved.
3. Determine how long the longest request should take. Factor in transaction times. You
may need to increase the reply_timeout to resolve the problem.
If this does not resolve the issue, continue to Step 4.
4. Determine if your current environment can handle the given load. If not, you may need to
upgrade or add more machines.
If this does not resolve the issue, continue to Step 5.
5. Confirm that there is no firewall blocking or dropping the AJP connections.
Procedure 4.4. 503 Errors
1. Optimize your Apache and JBoss configuration. You can contact Red Hat's Global
Support Services for assistance with this.
If this does not resolve the issue, proceed to St ep 2
2. Gather garbage collection logs for analysis.
If the logs show long garbage collection pause times then you should optimize the Java
Virtual Machine to reduce the garbage collection pauses and gather/recheck updated
logs. Refer to https://access.redhat.com/knowledge/solutions/19932 (Red Hat account
required) for more information.
If this is not the case, or does not resolve the issue, continue to St ep 3
3. Determine how long the longest request should take. Factor in transaction times. You
may need to increase the reply_timeout to resolve the issue.
If this does not resolve the issue, move on to Step 4.
4. Determine if your current environment can handle the given load. If not, you may need to
upgrade or add more machines.
JBoss/JVM-related Issue s
May present with errors like:
[error] service::jk_lb_worker.c (1473): All tomcat instances failed, no
more workers left
If Apache and JBoss are optimized and you still receive "no more workers left" this typically
indicates an issue on the JBoss/JVM side. A number of JVM-related problems could lead to
mod_jk not being able to get a connection to JBoss in the configured timeouts, thus causing the
worker to go into the error state and producing this message.
Procedure 4.5. JBoss/JVM Proble ms
1. Enable garbage collection logging.
a. For UNIX based systems, the options should be placed in run.conf, not run.sh.
The run.conf in the server configuration directory (e.g.
<JBOSS_HOME>/server/<PROFILE>/run.conf) takes precedence over the
run.conf in the <JBOSS_HOME>/bin directory (except in JBoss EAP 5.0.0 due to a
regression fixed in version 5.0.1).
18 Chapter 4. Troubleshooting and optimizing mod_jk