docker-compose.yml

version: '3' # Specifies the Docker Compose file format
services:  # Defines the services (containers) in your application
  # my-app:
  #   image: 235505018116.dkr.ecr.us-east-1.amazonaws.com/my-app:1.1
  #   ports:
  #     - 3000:3000
  mongodb:  # The service (container) name
    image: mongo  # Specifies the Docker Image to use 
    ports:  # Maps host port 27017 to container port 27017
      - 27017:27017
    environment:  # Sets environment variables for the container
      - MONGO_INITDB_ROOT_USERNAME=admin
      - MONGO_INITDB_ROOT_PASSWORD=password
    volumes:
      - mongo-data:/data/db    # host-volume-name:path-inside-the-container (path inside the container is provided by the documentation on DockerHub)
  mongo-express:
    image: mongo-express
    ports:
      - 8081:8081
    environment:
      - ME_CONFIG_MONGODB_ADMINUSERNAME=admin
      - ME_CONFIG_MONGODB_ADMINPASSWORD=password
      - ME_CONFIG_MONGODB_SERVER=mongodb
    restart: always  # This setting indicates that the container should be restarted automatically, no matter the reason for its exit.
volumes:
  mongo-data:
    driver: local