[LOG4J2-500] Unloading one webapp unloads JMX MBeans for all webapps

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0-rc1
• Fix Version/s: 2.0-rc1
• Component/s: JMX
• Assignee: Remko Popma
• Reporter: Remko Popma
• Created: 13/Jan/14 08:08
• Updated: 11/Jun/14 23:49
• Resolved: 07/Feb/14 14:54

Description

As a stopgap solution for LOG4J2-406, all MBeans are unregistered when a LoggerContext is stopped.

In an application server, multiple web applications can be deployed and undeployed independently and a better solution would only unregister the MBeans associated with the web application that is being undeployed.

Current MBean ObjectNames look like this (simplified):

...StatusLogger
...ContextSelector
...LoggerContext,ctx=%s
...LoggerConfig,ctx=%s,name=%s
...Appender,ctx=%s,name=%s
...

Assuming that every web application has a unique name, and this name becomes the name of the LoggerContext, then one solution would be to create StatusLogger and ContextSelector MBeans that have the LoggerContext name in their ObjectName:

...StatusLogger,ctx=%s
...ContextSelector,ctx=%s
...LoggerContext,ctx=%s
...LoggerConfig,ctx=%s,name=%s
...Appender,ctx=%s,name=%s
...

This way, every web application would have its own StatusLogger and ContextSelector MBeans. The MBeans may point to the same (shared) underlying StatusLogger and ContextSelector objects. When a web application is undeployed, unregistering all MBeans associated with the LoggerContext will not affect any MBeans associated with another web application (which has it own, separate, LoggerContext).

Issue Links

• depends upon: LOG4J2-529 Log4j2 does not auto-initialize on webapp deploy or auto-deinitialize on undeploy
• relates to: LOG4J2-578 JMX Memory Leak in Servlet Container
• relates to: LOG4J2-406 JMX MBeans are not being unregistered when a tomcat web application that uses log4j is undeployed, leading to a permgen memory leak.
• relates to: LOG4J2-530 JMX Client GUI should dynamically update when LoggerContext MBeans are registered/unregistered in MBean server
• relates to: LOG4J2-666 Ability to use a custom MBean domain