Node.js Hello World with Docker and k8s

Node.js is JavaScript runtime environment that executes JavaScript code outside of a browser.

Install on Mac

This step is not needed if you are planing to use docker.

Install with brew using

brew install node

After that check if it works with:

node -v

Quick script

Create file hello.js with:

console.log('Hello');

Then run it with

node hello.js

Hello world app

Create app.js with the following code

const http = require('http');
const os = require('os');

const port = 3000;

var handler = function(request, response) {
    console.log(
        "Received request from " + request.connection.remoteAddress
    ); 
    response.statusCode = 200;
    response.setHeader('Content-Type', 'text/plain');
    text = "Hello World\n" +
        "from " + os.hostname() + "\n";
    response.end(text);
};

const server = http.createServer(handler);
server.listen(port);

Run it with node app.js. Go to http://localhost:3000 or run

curl http://localhost:3000

Build with docker

Create Dockerfile:

FROM node:13
ADD app.js /app.js
ENTRYPOINT ["node", "app.js"]

Then build it with

docker build -t barteks/simple_node .

Change barteks to your Docker Hub username or simply remove barteks/ if you are not planing to push the image to Docker Hub.

Then run docker with

docker run -d -p 3000:3000 --name=simple_node barteks/simple_node

Check

curl http://localhost:3000

Push to docker hub

You can push built docker to Docker Hub by:

docker push barteks/simple_node

Run with k8s

See Kubernetes hello world for details how to install minikube.

Running docker on kubernetes cluster as simple as creating pod by:

kubectl run simplenode --image=barteks/simple_node\
    --port=3000 --generator=run-pod/v1

Then you need to create service in order to expose your pod:

kubectl expose pod simplenode --type=LoadBalancer --name simplenode-http

In minikube you have get access to local port by running

minikube service simplenode-http