https://github.com/easonlai/aks-java-alpine-openjdk-memory-dump

Taking Java Memory Dump from Containerized App running in AKS/K8S
https://github.com/easonlai/aks-java-alpine-openjdk-memory-dump

aks aks-kubernetes-cluster alpine alpine-image alpine-linux azure-kubernetes-service diagnostics docker docker-alpine java java-spring-boot javaspringboot jcmd jmap kubectl kubernetes kubernetes-cluster memory-dump tini

Last synced: about 1 month ago
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Taking Java Memory Dump from Containerized App running in AKS/K8S

• Host: GitHub
• URL: https://github.com/easonlai/aks-java-alpine-openjdk-memory-dump
• Owner: easonlai
• Created: 2021-07-07T06:31:37.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2021-07-07T06:34:40.000Z (over 3 years ago)
• Last Synced: 2024-11-10T23:39:04.964Z (3 months ago)
• Topics: aks, aks-kubernetes-cluster, alpine, alpine-image, alpine-linux, azure-kubernetes-service, diagnostics, docker, docker-alpine, java, java-spring-boot, javaspringboot, jcmd, jmap, kubectl, kubernetes, kubernetes-cluster, memory-dump, tini
• Language: Dockerfile
• Homepage:
• Size: 1000 Bytes
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Taking Java Memory Dump from Containerized App running in AKS/K8S

Special tricks to take Java memory dump from [Alpine](https://hub.docker.com/_/alpine) (e.g. [OpenJDK-Alpine](https://hub.docker.com/_/openjdk)) based container which running in [Azure Kubernetes Service (AKS)](https://docs.microsoft.com/en-us/azure/aks/intro-kubernetes). By adding [Tini](https://github.com/krallin/tini) as init of container, otherwise Java process in Alpine would be using PID 1 and would make "Unable to get pid of LinuxThreads manager thread" error when taking Java memory dump (same to [jcmd](https://docs.oracle.com/javase/8/docs/technotes/guides/troubleshoot/tooldescr006.html), [jstack](https://docs.oracle.com/en/java/javase/13/docs/specs/man/jstack.html)).

* Dockerfile <-- Sample Dockerfile with Tini, it's using [openjdk:8-jdk-alpine](https://hub.docker.com/layers/openjdk/library/openjdk/8-jdk-alpine/images/sha256-210ecd2595991799526a62a7099718b149e3bbefdb49764cc2a450048e0dd4c0?context=explore).

* [Containerized App sample in Java Springboot](https://github.com/easonlai/serving-web-content-demo)

Get list of POD running in AKS.

```shell

kubectl get pod

```

Run interactive terminal from container POD.

```shell

kubectl exec -it your-java-app-pod-name /bin/sh

```

Check Process ID (PID) running Java.

PID not equal to 1 should be our target to take memory dump.

```shell

top

```

Start to take memory dump.

```shell

cd /tmp

jmap -dump:format=b,file=snapshot.jmap 1

exit

```

Copy out memory dump from container to your development machine.

```shell

kubectl cp your-java-app-pod-name:tmp/snapshot.jmap snapshot.jmap -n your-pod-namespace

```