How to get a heap dump from Kubernetes k8s pod?

Question

Please provide a simple step by step guide to looking into java heap dump from a Kubernetes pod.

Answer 1

1. Log in to the K8S and exec into the Pods where your java application is running.

kubectl exec -it herle-deployment-pod-5757d89d85-wrpc9 bash

2. get the process id (top command)

3. Create java heap dump

jmap -dump:live,format=b,file=<file_name>.bin <process_id>

Example:

jmap -dump:live,format=b,file=application_heap_dump.bin 1

4. Copy the heap dump from pod to your local machine.

kubectl cp <pod_name>:<heap_file> <your local destination directory>

Example:

kubectl cp herle-deployment-pod-5757d89d85-wrpc9:/tmp/application_heap_dump.bin /Users/amritharajherle/Desktop/application_heap_dump.bin

5. Use any memory leak analysis tool. I'm using the Eclipse's Memory Analyzer plugin.

• Open the heap dump file

• select leak suspect report

• You can check the number of objects and retained heap space. Also some possible leak suspects.