JMX For Monitoring and Maintenance

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JMXFor Monitoring and Maintenance

• JA-SIG - December 4, 2005 Atlanta, GA
• Eric Dalquist
• Division of Information Technology
• University of Wisconsin Madison

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The Problem

• How to monitor and manage JVMs?
• Heap usage
• Threads
• Connection pools
• Simultaneous users

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Current Solutions

• Garbage collector logs
• Not the easiest to read
• Need to have a session open to each machine
• Custom monitoring code
• Cant always access interesting information
• Code you have to maintain and modify

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The JMX Solution

• Java Management eXtensions
• Open standard (JSR-160)
• API and tools included with Java 5
• Provides both Monitoring and Management

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Advantages of JMX

• Standards based means little or no coding
• Many applications already instrumented
• Existing tools to connect to MBean servers
• Frameworks to assist in instrumentation
• Very little impact on server performance

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Instrumentation

• MBeans Management beans
• JavaBean style objects
• Provide information
• Statistics, current state, overall summary
• Provide notifications
• Application events, values out of bounds
• Provide management
• Live configuration changes

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Instrumentation

• MBean Server
• MBeans are registered with the server
• Management tools connect to the server
• Aggregates information for tools
• Polls MBeans and manages data
• Manages MBean access rights

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Monitoring Management

• JMX Client
• Can view all exposed MBeans and properties
• Monitor multiple MBean servers (JVMs)
• Subscribe to MBean event notifications
• Modify writeable MBean properties

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JMX Clients

• JConsole
• Comes with Java 5 and later
• Swing based desktop application
• MC4J
• Open source Swing based desktop application
• Remembers server configuration
• Custom monitoring panel capabilities

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JMX Clients

• JManage
• Web based application
• Multiple users can monitor JVMs
• Can connect to multiple JVMs
• Organize JVMs into clusters
• 2.0 beta recently released
• Roadmap includes logging data to a database

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JConsole
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MC4J
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jManage
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JMX _at_ UW-Madison

• Metrics gathering for performance tuning
• Monitor heap usage and GC activity
• Tune caches resource pools during tests
• Monitoring production servers
• Watch for anomalies
• Gather usage statistics

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Performance Testing

• JMX adds another view of JVM metrics
• Heap usage for all three heap spaces
• Resource pool usage
• Cache performance and ratios
• Thread pool usage and sizing information

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JVM Summary
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Old Gen Heap
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Production Monitoring

• JConsole MC4J are used
• Heap usage for memory leaks
• Thread pools session counts for capacity
• Connection pools for database health
• Time spent doing garbage collection
• Portlet output caches query statistics

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Tomcat Thread Pool
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Portal Session Count
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How To Instrument

• Spring MBean exporter
• Easiest way to expose JavaBeans
• Only need to declare beans to be exposed
• Limited in exported bean configuration
• JDK MBean APIs
• Powerful API for describing data to export
• Non-trivial coding required

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JMX JA-SIG

• uPortal 3 Beans
• Using Spring MBean exporter
• Access to caches, thread pools, Hibernate stats
• Spring based portlets
• Export caching, statistics and usage data
• Bookmarks Portlet
• XSLT Portlet

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uPortal 3 RC1 Beans
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Bookmarks Portlet
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XSLT Portlet