This is an internal documentation. There is a good chance you’re looking for something else. See Disclaimer.

Debugging via JMX

JMX provides basic debugging capabilities, is shipped with Java and enabled by default.

Tip

This is enabled for most Java applications, not just Nice, including our address provider and commit info service.

When connecting to JMX using VisualVM or JConsole it possible, to:

  • show application configuration

  • monitor cpu, memory and threads

  • profile cpu and memory

  • obtain core, heap and thread dumps

Note

For local debugging, YourKit is generally superior. While it is also possible to use it for remote debugging, the required agent is not currently included and configured on OpenShift. Licenses are available.

Forward JMX Port

Locally, JMX uses an auto-discover mechanism. On OpenShift, this isn’t possible and port 30200 is hardcoded instead.

  1. Get pod name:

    $ oc get pods
NAME             READY   STATUS    RESTARTS   AGE
nice-380-gtt9g   2/2     Running   0          2d

  2. Forward connection:

    oc port-forward nice-380-gtt9g 30200

Connect via VisualVM

Install VisualVM:

apt install visualvm

Connect via VisualVM:

visualvm --openjmx localhost:30200

Screenshots:

../../_images/vvm-overview.png

VisualVM - Overview

../../_images/vvm-monitor.png

VisualVM - Monitor

../../_images/vvm-threads.png

VisualVM - Threads

../../_images/vvm-sampler-cpu.png

VisualVM - Sampler - CPU

../../_images/vvm-sampler-memory.png

VisualVM - Sampler - Memory

See also:

Connect via JConsole

Connect via JConsole:

jconsole service:jmx:rmi:///jndi/rmi://localhost:30200/jmxrmi

Screenshot:

../../_images/jconsole-overview.png

JConsole - Overview