Compose 入门指南

Compose is a tool for defining and running multi-container Docker applications.

Docker Compose 是 Docker 的编配工具，用于完成自动配置、协作和管理服务等过程。

Compose 安装

因为 docker-compose 使用 Python 编写，所以可以使用 pip 直接安装：

$ pip install -U docker-compose

Tip

docker-compose 命令较长，可以使用 alias 指定别名：

# .bashrc
alias dc="docker-compose"

使用 docker-compose -h 可以查看命令帮助，常用命令：

• build
• logs
• ps
• rm
• stop
• up

运行 Compose

这里同时启动 8 个 spider 服务：

$ docker-compose up -d --scale spider=8

Compose 命令

使用命令 docker-compose --help 可查看命令工具支持的命令和参数，docker-compose help [COMMAND] 查看命令详情。

Define and run multi-container applications with Docker.

Usage:
  docker-compose [-f <arg>...] [options] [COMMAND] [ARGS...]
  docker-compose -h|--help

Options:
  -f, --file FILE            Specify an alternate Compose file (default: docker-compose.yml)
  -p, --project-name NAME    Specify an alternate project name (default: directory name)
  --verbose                  Show more output
  --no-ansi                  Do not print ANSI control characters
  -v, --version              Print version and exit
  -H, --host HOST            Daemon socket to connect to

  --tls                      Use TLS; implied by --tlsverify
  --tlscacert CA_PATH        Trust certs signed only by this CA
  --tlscert CLIENT_CERT_PATH  Path to TLS certificate file
  --tlskey TLS_KEY_PATH      Path to TLS key file
  --tlsverify                Use TLS and verify the remote
  --skip-hostname-check      Don't check the daemon's hostname against the name specified
                              in the client certificate (for example if your docker host
                              is an IP address)
  --project-directory PATH    Specify an alternate working directory
                              (default: the path of the Compose file)

Commands:
  build              Build or rebuild services
  bundle            Generate a Docker bundle from the Compose file
  config            Validate and view the Compose file
  create            Create services
  down              Stop and remove containers, networks, images, and volumes
  events            Receive real time events from containers
  exec              Execute a command in a running container
  help              Get help on a command
  images            List images
  kill              Kill containers
  logs              View output from containers
  pause              Pause services
  port              Print the public port for a port binding
  ps                List containers
  pull              Pull service images
  push              Push service images
  restart            Restart services
  rm                Remove stopped containers
  run                Run a one-off command
  scale              Set number of containers for a service
  start              Start services
  stop              Stop services
  top                Display the running processes
  unpause            Unpause services
  up                Create and start containers
  version            Show the Docker-Compose version information

其中，最常用的命令为：

build

build 根据 docker-compose 文件指定的镜像和选项构建镜像，如果事先使用 Dockerfile 编译好镜像则无需 build，直接使用 up 启动。

$ docker-compose build

up

类似 Docker，Compose 使用 up 启动容器，使用制定的参数来执行，并将所有的日志输出合并到一起。

$ docker-compose up

如果启动时指定 -d 标志，则以守护进程模式运行服务。

$ docker-compose up -d

如果要批量启动服务（如启动 8 个 Scrapy），则在 --scale 选项指定服务的个数：

$ docker-compose up -d --scale spider=8

ps

ps 列出本地 docker-compose.yml 文件里定义的正在运行的所有服务。

$ docker-compose ps

logs

logs 查看服务的日志，这个命令会追踪服务的日志文件，类似 tail -f 命令，使用 Ctrl+C 退出。

$ docker-compose logs

stop

stop 停止所有服务，如果服务没有停止，可以使用 docker-compose kill 强制杀死服务。

$ docker-compose stop

rm

rm 删除所有服务。

$ docker-compose rm

一个例子

最后，以一个官方 docker-compose.yml 结束：

version: "3"
services:

  redis:
    image: redis:alpine
    ports:
      - "6379"
    networks:
      - frontend
    deploy:
      replicas: 2
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure
  db:
    image: postgres:9.4
    volumes:
      - db-data:/var/lib/postgresql/data
    networks:
      - backend
    deploy:
      placement:
        constraints: [node.role == manager]
  vote:
    image: dockersamples/examplevotingapp_vote:before
    ports:
      - 5000:80
    networks:
      - frontend
    depends_on:
      - redis
    deploy:
      replicas: 2
      update_config:
        parallelism: 2
      restart_policy:
        condition: on-failure
  result:
    image: dockersamples/examplevotingapp_result:before
    ports:
      - 5001:80
    networks:
      - backend
    depends_on:
      - db
    deploy:
      replicas: 1
      update_config:
        parallelism: 2
        delay: 10s
      restart_policy:
        condition: on-failure

  worker:
    image: dockersamples/examplevotingapp_worker
    networks:
      - frontend
      - backend
    deploy:
      mode: replicated
      replicas: 1
      labels: [APP=VOTING]
      restart_policy:
        condition: on-failure
        delay: 10s
        max_attempts: 3
        window: 120s
      placement:
        constraints: [node.role == manager]

  visualizer:
    image: dockersamples/visualizer:stable
    ports:
      - "8080:8080"
    stop_grace_period: 1m30s
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
    deploy:
      placement:
        constraints: [node.role == manager]

networks:
  frontend:
  backend:

volumes:
  db-data: