docker-compose.yaml

version: '2.2'

services:
  awesome:
   image: awesome
   ports:
     - 8080
   scale: 20
   networks:
      - front-tier
      - back-tier

  lb:
      image: dockercloud/haproxy
      ports:
        - 80:80
      links:
        - awesome
      networks:
        - front-tier
        - back-tier
      volumes:
        - /var/run/docker.sock:/var/run/docker.sock 

networks:
  front-tier:
    driver: bridge
  back-tier:
    driver: bridge

Dockerfile

FROM node
RUN mkdir -p /usr/src/app
COPY index.js /usr/src/app
EXPOSE 8080
CMD [ "node", "/usr/src/app/index" ]

index.js

var http = require('http');
var os = require('os');
http.createServer(function (req, res) {
    res.writeHead(200, {
        'Content-Type': 'text/html'
    });
    res.end(`<h1>I'm ${os.hostname()}</h1>`);
}).listen(8080);