Docker Compose cheat sheet

# docker-compose.yml
version: '3'
​
services:
  web:
    build: .
    # build from Dockerfile
    context: ./Path
    dockerfile: Dockerfile
    ports:
     - "5000:5000"
    volumes:
     - .:/code
  redis:
    image: redis

web:
  # build from Dockerfile
  build: .
  # build from custom Dockerfile
  build:
    context: ./dir
    dockerfile: Dockerfile.dev
  # build from image
  image: ubuntu
  image: ubuntu:14.04
  image: tutum/influxdb
  image: example-registry:4000/postgresql
  image: a4bc65fd

ports:
  - "3000"
  - "8000:80"  # guest:host
# expose ports to linked services (not to host)
expose: ["3000"]

# command to execute
command: bundle exec thin -p 3000
command: [bundle, exec, thin, -p, 3000]
​
# override the entrypoint
entrypoint: /app/start.sh
entrypoint: [php, -d, vendor/bin/phpunit]

# environment vars
environment:
  RACK_ENV: development
environment:
  - RACK_ENV=development
​
# environment vars from file
env_file: .env
env_file: [.env, .development.env]

# makes the `db` service available as the hostname `database`
# (implies depends_on)
links:
  - db:database
  - redis
​
# make sure `db` is alive before starting
depends_on:
  - db

# make this service extend another
extends:
  file: common.yml  # optional
  service: webapp
volumes:
  - /var/lib/mysql
  - ./_data:/var/lib/mysql

services:
  web:
    labels:
      com.example.description: "Accounting web app"

services:
  web:
    dns: 8.8.8.8
    dns:
      - 8.8.8.8
      - 8.8.4.4

services:
  web:
    devices:
      - "/dev/ttyUSB0:/dev/ttyUSB0"

services:
  web:
    external_links:
      - redis_1
      - project_db_1:mysql

services:
  web:
    extra_hosts:
      - "somehost:192.168.1.100"

# creates a custom network called `frontend`
networks:
  frontend:

# join a preexisting network
networks:
  default:
    external:
      name: frontend