pmgysel / demo-docker-kubernetes

Example for containerizing an app and running it on a Kubernetes cluster

Simple Demo for Docker & Kubernetes

Prerequisites

• Maven
• Java
• Docker
• Kubernetes
• Curl

Install and run Docker & Kubernetes locally (Linux/Windows/Mac): https://docs.docker.com/get-docker/

Run app on your OS

REST endpoints:

• GET localhost:8080/actuator/health: health endpoint
• GET localhost:8080/api/ping: get PONG message

Get source code, compile app and run app:

> git clone https://github.com/pmgysel/demo-docker-kubernetes.git
> cd demo-docker-kubernetes
> mvn clean install
> java -jar target/demo-docker-kubernetes-0.0.1-SNAPSHOT.jar

Test running app in second terminal:

> curl -X GET localhost:8080/api/ping

Hello world, here is demo-docker-kubernetes version 0.0.1-SNAPSHOT

Docker demo

Option 1: Create Docker image from JAR

> docker build -t demo-docker-kubernetes:0.0.1 -f Dockerfile.from.artifact .

Option 2: Create Docker image from source

> docker build -t demo-docker-kubernetes:0.0.2 -f Dockerfile.from.source .

... then run the image inside a Docker container:

> docker run -p 8080:8080 demo-docker-kubernetes:0.0.1
> curl -X GET localhost:8080/api/ping

Hello world, here is demo-docker-kubernetes version 0.0.1-SNAPSHOT

Clean up everything:

> docker ps
CONTAINER ID     IMAGE                          COMMAND                  CREATED  ....
af2b2f9d190c     demo-docker-kubernetes:0.0.1   "/bin/sh -c 'java -j…"   8 seconds ...
> docker stop af2b2f9d190c

Kubernetes demo

> cd kubernetes
> kubectl apply -f deployment.yaml
> kubectl get deployments
NAME              READY   UP-TO-DATE   AVAILABLE   AGE
demo-deployment   1/1     1            1           11s
> kubectl get pods
NAME                              READY   STATUS    RESTARTS   AGE
demo-deployment-5ffc866f6-4ffsg   1/1     Running   0          31s
> kubectl apply -f service.yaml
> kubectl get services
NAME           TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)          AGE
demo-service   NodePort    10.98.86.21   <none>        8080:30001/TCP   19s
> curl -X GET http://localhost:30001/api/ping

Hello world, here is demo-docker-kubernetes version 0.0.1-SNAPSHOT

Finally, clean up running pods and services:

> kubectl delete deployment demo-deployment
> kubectl delete service demo-service