kanedafromparis / resourcesmonger

This is a sample application used for my kubernetes introduction course

ressouresmonger

This is a sample application used for my kubernetes introduction course

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Purpose

The purpose of this application is to show that jvm (1.8) does does take docker (cgroups) limits in its usage of ressources.

This is a simple sever with :

curl $(minikube service resourcesmonger --url)/api/1.0/infos/env | jq .

to displays it's env variables

curl $(minikube service resourcesmonger --url)/api/1.0/kaboom/ram | jq .

to make it consume RAM to the Exception java.lang.OutOfMemoryError: Java heap space, that should conduct to a crash and respawn of a pod.

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
 ...
spec:
  ...
  template:
    ...
    spec:
      containers:
      - env:
        - name: JVM_OPTIONS
          value: "-Djava.security.egd=file:/dev/./urandom -Xmx1g -XshowSettings:vm"
        image: kanedafromparis/resourcesmonger:0.1
        imagePullPolicy: IfNotPresent
        name: resourcesmonger
        resources:
          limits:
            memory: 256Mi
...

curl $(minikube service resourcesmonger --url)/api/1.0/kaboom/ram | jq . 

the pod is killed before java.lang.OutOfMemoryError.

Usage

Build

mvn package && \
  docker build -t $USER/resourcesmonger:1.0 . -f src/main/docker/Dockerfile && \
  kubectl run resourcesmonger --image $USER/resourcesmonger:1.0 --port 8080 && \
  kubectl expose deployment resourcesmonger --type=NodePort

Check the logs

kubectl logs -f $(kubectl get pod -l run=resourcesmonger --no-headers | cut -d " " -f 1)

clean

kubectl delete -l run=resourcesmonger

Todo

• Looka at the Sprind and Vertx version (maybe)
• used the fabric8 plugin (maybe)