This document discusses techniques for troubleshooting issues with Red Hat JBoss EAP 6. It covers generating thread dumps, heap dumps, and log files to analyze where threads are stuck or understand memory usage. The JBoss Diagnostic Reporter (JDR) subsystem can collect troubleshooting information. Byteman allows inserting extra Java code into applications to aid debugging. The log subsystem level and GC logging can be configured for additional troubleshooting data in log files.

1. Red Hat JBoss EAP 6
Troubleshooting
Alexandre Cavalcanti
Middleware Technical Account Manager
acavalcanti@redhat.com

2. JBoss Troubleshooting - Alexandre Cavalcanti2
AGENDA
Introduction
Dumps
Logs
Byteman

3. JBoss Troubleshooting - Alexandre Cavalcanti3
There are many different types of problems or erros (Memory Leaks,
Transaction Failures, Performance problems, JBoss remoting errors, Data
inconsistencies, JVM Garbage Collection, Bad Application Code, Deadlocks
Timeouts, System integration issues etc).
How to troubleshoot them?
Introduction

4. JBoss Troubleshooting - Alexandre Cavalcanti4
Thread Dump
The thread dump is a snapshot of exactly what's executing at a moment in
time.
Useful if your Java application sometimes seems to hang when running under
load, as an analysis of the dump will show where the threads are stuck.
JSTACK
• Check PID and user of Java process by executing ps command:
• ps aux | grep java
• Execute jstack command as JBoss user:
• $su - <JAVA_USER>
• $jstack -l <JAVA_PID>
https://access.redhat.com/solutions/18178
Dumps

5. JBoss Troubleshooting - Alexandre Cavalcanti5
Heap Dump
A heap dump is a snapshot of memory at a given point in time. It contains
information on the Java objects and classes in memory at the time the
snapshot was taken.
A heap dump can also help you understand the memory footprint of your app
• -XX:+HeapDumpOnOutOfMemoryError
• <server-groups>
• <server-group name="main-server-group" profile="ha">
• <jvm name="default">
• …
• <jvm-options>
• <option value="-XX:+HeapDumpOnOutOfMemoryError"/>
• </jvm-options>
• https://access.redhat.com/solutions/21109
Dumps

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Jitter and Log files
The JBoss Diagnostic Reporter (JDR pronounced jitter) is an EAP6 subsystem
built to collect information to aid in troubleshooting.
• [domain@localhost:9999 /] /host=$host/server=$server/subsystem=jdr/:generate-jar-
report
Add a log level do the log subsystem
• /profile=full-ha/subsystem=logging/logger=org.jboss.jca:add(level=TRACE)
Garbage Collection (GC) logging
• /host=master/jvm=default/:write-attribute(name=jvm-options,value=["-server","-
verbose:gc “,”-Xloggc:gc.log"])
https://access.redhat.com/solutions/221103
https://access.redhat.com/solutions/459903
https://access.redhat.com/solutions/269023
Logs

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Byteman allows you to insert extra Java code into your application, either as it
is loaded during JVM startup or even after it has already started running. The
injected code is allowed to access any of your data and call any application
methods, including where they are private.
• JAVA_OPTS="$JAVA_OPTS -javaagent:<mypath>/lib/byteman.jar=script:<mypath>/
examplescript.btm,sys:<mypath>/lib/byteman.jar”Bullet
https://access.redhat.com/solutions/31283
http://byteman.jboss.org/
Byteman

8. Questions?