JMXFetch

In the Agent, the yaml files for the following integrations are all read by JMXFetch:

• Active MQ
• Cassandra
• Java
• Solr
• Tomcat

JMXFetch attributes

There are two kinds of JMX attributes that JMXFetch is able to collect (simple and composite).

Simple attributes

These are integer, float, double, long, boolean etc …

Note: Boolean values of true result in 1 and false in 0. Check the list of supported types

You can use the list commands in order to get an idea of what your current JMX integration is collecting. Here is a snippet of that output showing a Simple attribute:

Matching: x/350. Bean name: java.lang - Attribute name: attribute_1 - Attribute type: java.lang.Integer

That would give you the following configuration:

- include:
     domain: java.lang
     attribute:
       attribute_1:
         metric_type: counter
         alias: java.lang.Integer

JMXFetch extracts the attribute value directly and use it as the metric value. See the JMX documentation to learn how to collect it.

Composite attributes

These can be seen as an array, a hashmap, or an object composed of ‘simple’ attributes.

Matching: x/350. Bean name: java.lang - Attribute name: HeapMemoryUsage - Attribute type: javax.management.openmbean.CompositeData

In this case, you need to add more details to JMXFetch on how to use this ‘composite’ attribute to create a numerical value for a metric.

To do this, use a . to specify the component:

- include:
    domain: java.lang
    type: Memory
    attribute:
      HeapMemoryUsage.used:
        alias: jvm.heap_memory
        metric_type: gauge
      HeapMemoryUsage.committed:
        alias: jvm.heap_memory_committed
        metric_type: gauge

      # (...)

How can I get to see the next level of these composite attributes?

The best way to achieve this would be using JMXterm (see below).

java -jar /opt/datadog-agent/agent/checks/libs/jmxterm-1.0-DATADOG-uber.jar -l localhost:<PORT> -u <USER> -p <PASSWORD>

Note, for all versions of Agent v5.32.8 or greater, the jmxterm JAR is not shipped with the Agent. To download and use jmxterm, see the upstream project.

Then use the get command to pull up a specific metric.