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JMX Query

You can configure MetricsHub to periodically query any Java application exposing JMX (Java Management Extensions), retrieve specific MBean attributes, and push OpenTelemetry metrics with the extracted values.

In the example below, we configure MetricsHub to:

  • monitor the java-app resource using JMX
  • retrieve the LoadedClassCount attribute from the java.lang:type=ClassLoading MBean
  • expose the value as an OpenTelemetry metric named jvm.class.count

Procedure​

To achieve this use case, we:

  • Declare the resource to be monitored (java-app) and its attributes (host.name, host.type):

    resources:
      java-app:
        attributes:
          host.name: java-app
          host.type: linux

  • Configure the jmx protocol:

        protocols:
          jmx:
            port: 1099
            username: myUser
            password: myPassword
            timeout: 60s

  • Define a monitor job (jvm) to collect the JVM class loading metric:

        monitors:
          jvm:
            simple:

  • Set up a JMX source (JvmClassLoading) to retrieve the LoadedClassCount attribute from the java.lang:type=ClassLoading MBean:

              sources:
                JvmClassLoading:
                  type: jmx
                  objectName: java.lang:type=ClassLoading
                  attributes:
                    - LoadedClassCount

  • Extract and expose the metric (jvm.class.count) from the JMX response:

              mapping:
                source: ${source::JvmClassLoading}
                attributes:
                  id: java-app-classloading
                metrics:
                  jvm.class.count: $1

Complete Configuration​

resources:
  java-app:
    attributes:
      host.name: java-app
      host.type: linux
    protocols:
      jmx:
        port: 1099
        username: myUser
        password: myPassword
        timeout: 60s
    monitors:
      jvm:
        simple:
          sources:
            JvmClassLoading:
              type: jmx
              objectName: java.lang:type=ClassLoading
              attributes:
                - LoadedClassCount
          mapping:
            source: ${source::JvmClassLoading}
            attributes:
              id: java-app-classloading
            metrics:
              jvm.class.count: $1

Supporting Resources​