Analysing Java GC in Kubernetes Without Stopping or Changing Anything

Get the current Java memory and GC without restarting with just kubectl exec or docker exec access

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Do you run Java in Kubernetes or Docker and need to quickly analyze the Java memory and GC behavior without stopping the process/container?

Is the container running in a protected cluster on which you can only run kubectl and you can’t add JMX or other ports?

Are you running a Java-based container but don’t want to include jstat or other tools?

Here’s a solution.

Note: this will work for any Java HotSpot based JVM.

This solution assumes an “airgap” environment (without internet access) and will allow you to achieve the following progressively:

• Quickly have a terminal-based glance at the current Java memory and GC metrics for a running container
  (steps 1 to 3)

Terminal-based

• Pipeline the Java memory and GC metrics gathered to a local Prometheus/Grafana setup to analyze them near real-time
  (step 4)