Splunk Java Agent v0.5b

Overview

This JVM(Java Virtual Machine)agent can be used to obtain metrics for Java APM(Application Performance Monitoring).

The types of metrics extracted by the agent and streamed to Splunk are :

1. class loading
2. method execution
3. method timings (cumulative, min, avg, max, std deviation)
4. method call tracing(count of calls, group by app/app node(for clustered systems)/thread/class/package)
5. application/thread stalls
6. errors/exceptions/throwables
7. JVM heap analysis, object/array allocation count/size,class dumps, leak detection, stack traces, frames
8. JMX attributes/operations/notifications from the JVM or Application layer MBean Domains

The agent is able to obtain these metrics dynamically at runtime by "weaving" the necessary bytecode into loaded classes using the Java instrumentation API and the ASM framework. There is no source code changes required by the end user and no class files on disk are altered.

JMX metrics are obtained via polling MBeans attributes, invoking operations & listening for notifications in the locally running Platform MBeanServer.

JVM heap profiling metrics are obtained via decoding a dynamically generated HPROF dump.

By default , the metrics will be streamed directly into Splunk over TCP, however the transport mechanism is configurable and extensible.

In the Splunk UI you can then create Splunk searches over the agent data and visualizations, reports,alerts etc.. over the results of the searches. The events are already being fed into Splunk in best practice semantic format, key=value pairs , no additional field extractions are required. As Splunk is being using to index all the data and perform searches(real time if you wish) massive amounts of tracing data from as many JVMs as you need to monitor can be indexed and correlated and you can leverage all of the scalability and HA features of the Splunk platform to deliver an end to end Java APM solution.

Supported Java Runtime

1. JRE 5+
2. JVMs : Hotspot , JRockit, OpenJDK, IBM J9

Install

1. Uncompress splunkagent.tar.gz
2. The agent is just a single jar file, splunkagent.jar, you should see this in the uncompressed directory.

Setup

Pass the follow argument to your JVM at startup:

-javaagent:splunkagent.jar

or

-javaagent:lib/splunkagent.jar

etc..

The location of the jar file should be relative to the directory where you are executing "java" from.

All dependencies and resources are bundled into the jar file.

Configuration

You can configure the agent with the properties file "splunkagent.properties" that resides inside the jar file. The various options are detailed below. Open the jar , edit the file, close the jar.

Note : unless you want incredibly verbose tracing , you will want to specify just the packages/classes/methods you are interested in profiling in the "agent.whitelist" property

You can configure the JMX polling with 1 or more config files that reside inside the jar file. The JMX logic is just an embedded version of the "Splunk for JMX" app(http://splunk-base.splunk.com/apps/25505/splunk-for-jmx) , so refer to that app's documentation for config file options. The names of the JMX config files and the frequency at which they are fired is configured in "splunkagent.properties"

Properties Options

• agent.app.name : name of the application ie: Tomcat

• agent.app.instance : instance identifier of the application ie: might be a node id in a cluster

• agent.userEventTags : comma delimited list of user defined key=value pairs to add to events sent to Splunk

• splunk.transport.internalQueueSize : defaults to 10000 events , this the internal memory queue that buffers the events before being sent to Splunk.

• splunk.transport.impl : fully qualified class name, an implementation of the "com.splunk.javaagent.transport.SplunkTransport" interface

• splunk.transport.tcp.host : Splunk host name for the SplunkTCPTransport

• splunk.transport.tcp.port : Splunk TCP port for the SplunkTCPTransport

• splunk.transport.tcp.maxQueueSize : defaults to 500K , format [|[KB|MB|GB]]

• splunk.transport.tcp.dropEventsOnQueueFull : true | false , if true then the queue will get emptied when it fills up to accommodate new data.

• trace.whitelist : comma delimited string of patterns, see below

• trace.blacklist comma delimited string of patterns, see below

• trace.methodEntered : true | false

• trace.methodExited : true | false

• trace.classLoaded : true | false

• trace.errors : true | false

• trace.hprof=true | false

• trace.hprof.file=/etc/tmp/dump.hprof

• trace.hprof.frequency=value in seconds , the frequency at which to generate hprof dumps

• trace.hprof.recordtypes=comma delimited list of HPROF record types to trace.Decimal value of the record tag id (as per the HPROF spec).

• trace.jmx=true | false

• trace.jmx.configfiles=comma delimited list of XML files(minus the ".xml" suffix) that should reside in the root of splunkagent.jar

• trace.jmx.default.frequency=value in seconds

• trace.jmx.${configfile}.frequency=value in seconds , optionally you may declare each config file to fire at differing frequencys

Whitelist/Blacklist Patterns

• Partial package name : com/splunk/
• Full package name : com/splunk/javaagent/test/
• Fully qualified class : com/splunk/javaagent/test/MyClass
• Fully qualified class and method : com/splunk/javaagent/test/MyClass:someMethod

Contact

This project was initiated by Damien Dallimore

Email	ddallimore@splunk.com
Twitter	@damiendallimore