Java Hello World in a Kubernetes Container

Just a simple little jva console app to heartbeat to the console. Used for testing Kubernetes, and Application Performance Monitoring of Kubernetes. If you need to have a continer running to troubleshoot monitoring this will fill the bill while consuming relatively small amounts of resources.

Building

All commands are for Windows Powershell. Most will work in bash, except the $timestamp function. If you are working in bash you'll need to translate that.

Login to Docker Hub

# Note, your username is not your email address. Login from the browser to see what your username is.
docker login

Build Docker Image

$timestamp = (Get-Date).tostring("yyyyMMddhhmmss")
docker build -t javahello:$timestamp .
docker tag javahello:$timestamp javahello:latest

Set up a local docker repository for Kubernetes to read from

docker run -d -p 5000:5000 --restart=always --name registry registry:2

Push the docker image to the local registry

docker tag javahello:latest localhost:5000/javahello:latest
docker push localhost:5000/javahello:latest

Deploy to Kubernetes

kubectl apply -f deployment.yaml

Check that the Pod is running

kubectl get pods

Watch the logs from the container

kubectl logs pod/javahello-967b669b-nbzvk --namespace=default --container=javahello -f

Remove the deployment

kubectl delete deployment javahello