image 使用的镜像
build 指定Dockerfile构建
command 启动执行命令
links 链接其他容器
ports 端口映射
expose 暴露端口
volumes 挂载路径
volumes_from 从容器挂载
environment 环境变量

举个栗子：

mx_mysql:
  restart: always
  image: mysql:5.6
  volumes:
    - /root/data/mysql:/var/lib/mysql
    - ./conf/:/etc/mysql/conf.d
  ports:
    // 前面的3306表示宿主容器的端口，后面的3306表示容器内部的端口
    - "3306:3306"
  environment:
    - MYSQL_DATABASE=online
    - MYSQL_ROOT_PASSWORD=123456
  
mx_redis:
  restart: always
  image: redis:3.2
  volumes:
    - /root/data/redis:/data
  ports:
    - "6379:6379"
  command: redis-server --appendonly yes

mx_nginx:
  restart: always
  image: nginx
  ports:
    - "80:80"
  volumes:
    - ./conf/mx_nginx.conf:/etc/nginx/conf.d/mx_nginx.conf
  volumes_from:
    - mx_online
  links:
    - mx_online:web

mx_online:
  restart: always
  build: .
  expose:
    - "8000:8000"
  volumes:
    - .:/online
  links:
    - mx_mysql:mysql
    - mx_redis:redis
  command: uwsgi -s :8000 -w online.wsgi -p 3

mx_celery:
  restart: always
  build: .
  volumes_from:
    - mx_online
  links:
    - mx_mysql:mysql
    - mx_redis:redis
  command: celery -A online worker -l info

启动的命令：docker-compose up -d 后台启动应用