Thermostat

An Open SourceInstrumentation Tool for theHotspot JVM

Severin Gehwolf, Red HatMario Torre, Red Hat

Developer Conference 2013

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Agenda

● What is it exactly this Thermostat?● How does Thermostat work?● Current and upcoming features● Thermostat plug-ins 101● Demo/Hack Session

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The Tool Explained(a.k.a. What is this tool exactly?)

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What is Thermostat?

Monitoring

Diagnostics

Tuning

Profiling

OpenSource

OpenJDK

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What is Thermostat?

Monitoring

Diagnostics

Tuning

Profiling

OpenSource

OpenJDK

Information Hub

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What is Thermostat?

AS

JVM

OS

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What is Thermostat?

AS

JVM

OS

Vertical Integration

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What is Thermostat?

Local Remote Cluster Cloud?

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What is Thermostat?

Horizontal Integration

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Lines of Code

Source: https://www.ohloh.net/p/thermostat-monitoring-tool

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Commits Per Month

Source: https://www.ohloh.net/p/thermostat-monitoring-tool

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Current and Upcoming Features

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Current Features

● CPU monitoring

● Memory usage

● GC invocations

● Thread monitoring

● Heap dump analysis

● Classloader information

● Numa

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Upcoming Features

● Finish NUMA support● JVM tuning● Systemtap / oprofile backend● Memory leak & deadlock analysis● Eclipse client/IDE integration● Web client● Host / JVM issues overview● Open Shift deployment. Maybe?

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Cool!How Does It Work?

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Agent, Client, Storage Approach

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How Does It Work?

Agents

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How Does It Work?

Storage

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How Does It Work?

Clients

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Where Is The Data Coming From?

● JvmStat

● JMX

● /proc

● Systemtap

● Oprofile

● App Server

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Where Is The Data Coming From?

● JvmStat

● JMX

● /proc

● Systemtap

● Oprofile

● App Server

At Present

In Future

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Plug-in 101

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The Basics (1)

● Extensible through plug-ins

● OSGi

● Write your own agent extensions

● Write your own client extensions

● plugin.xml file tells Thermostat about your new

bundles

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Recall...

Agents

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Agent Extensions

Numa

Backends

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Storage Extensions

NumaDAO

DAOs

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Client Extensions

InformationService

VmRef HostRef

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The Basics (2)

● Backend's extend agents

● Data Access Objects (DAO) extend Storage

● InformationService's extend GUI

● Can bind UI to...

– HostRef (a specific host/agent)

– VmRef (a specific JVM)

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plugin.xml<?xml version="1.0" ?><plugin> <commands> <command type="extends"> <name>gui</name> <bundles> <bundle>your-plugin-0.1-SNAPSHOT.jar</bundle> </bundles> </command> <command type="provides"> <name>hello</name> <description>Prints hello</description> <usage>hello</usage> <bundles> <bundle>your-hello-world-plugin-0.1-SNAPSHOT.jar</bundle> </bundles> <dependencies> <dependency>thermostat-client-core-0.6.0-SNAPSHOT.jar</dependency> </dependencies> </command> </commands></plugin>

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Questions?

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Why This New Tool?

● Scalability● Avoiding unwanted dependencies.● Written in Java, by Java devs, for Java devs.● Flexible data model● Developer ego (This is joke. You laugh

now).

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Demo/Hack Session Time!

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References

● Homepage: http://icedtea.classpath.org/thermostat/

● Code: http://icedtea.classpath.org/hg/thermostat

● Mailing list: http://icedtea.classpath.org/mailman/listinfo/thermostat

● IRC: #thermostat on freenode.net

● Duke images from around the net

● http://jroller.com/neugens/entry/thermostat_scheduler_plugin_a_walk

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Thank You!Kudos to Mario and Omair for providing most of the plug-in code!