Java Demo Application

Java Demo Application for Kubernetes.

Overview

The demo runs on HTTP port 8080, and provides the current system environment variables formatted as an ASCII table:

This is useful for exploring the environment of a Kubernetes pod. For example, the HOSTNAME variable tells which pod is serving the request.

Run

A pre-built Docker image is available on fstab/java-demo. Test locally:

docker run -p8080:8080 --rm fstab/java-demo

Deploy on Kubernetes

curl -LO https://raw.githubusercontent.com/fstab/java-demo/master/java-demo.yaml
kubectl create -f java-demo.yaml

Build

This demo requires Java 11.

Option 1: Build the Docker image manually:

mvn package
docker build -t fstab/java-demo .

Option 2: Build using the Docker maven plugin:

mvn package docker:build

Test

Test locally:

View http://localhost:8080.

Test on Kubernetes:

1. Get the service's Cluster IP:

   export DEMO_SERVICE_IP=$(kubectl get service java-demo -o=jsonpath='{.spec.clusterIP}')

2. Access the pods through the service's Cluster IP:

   curl $DEMO_SERVICE_IP

Notes

You see a compile error in Intellij Idea? Me too, filed this bug report https://youtrack.jetbrains.com/issue/IDEA-203791.