docker-compose.yml

# Use docker-compose syntax Version 2
version: "2"

services:
  # Our main "nodeapp" service which has the express aplication inside
  nodeapp1:
    build:
      # Look for the Dockerfile inside the "nodeapp" folder
      context: ./nodeapp
      dockerfile: Dockerfile
    restart: always
    ports:
      - "80"
    networks:
      - front-tier
  
  # Our replicas of the main "nodeapp", just so that NGINX can load-balance
  # E.g when there's a new version available of our app
  # We'll take each one of these 3 services done, update them and bring them back up 1-by-1
  nodeapp2:
    extends:
      service: nodeapp1
  
  nodeapp3:
    extends:
      service: nodeapp1
  
  # NGINX will reverse proxy the express application
  nginx:
    build: ./nginx
    restart: always

    # Bind port 80 in the service to port 80 on the host
    ports:
        - "80:80"
    networks:
      - front-tier

networks:
  front-tier:
    driver: bridge