前提

• dockers version:1.13或者更高(17.03.1-ce)
• 安裝Docker Compose

理解service

在一個分布式應用中，不同的部分都被稱為service。

services實際上是containers in production。一個service啟動一個image，它規(guī)定了image的運行方式(使用哪些端口，需要多少個container的復制集才能滿足service等)。

docker-compose.yml文件可以很簡單的定義、運行、規(guī)劃services。

docker-compose.yml

可以把該文件保存在任何位置。確保image已經上傳。

version: "3"
services:
  web:
    # replace username/repo:tag with your name and image details
    image: username/repository:tag
    deploy:
      replicas: 5
      resources:
        limits:
          cpus: "0.1"
          memory: 50M
      restart_policy:
        condition: on-failure
    ports:
      - "80:80"
    networks:
      - webnet
networks:
  webnet:

• 從registry拉取image
• 運行5個image的實例作為服務，稱為web，限制每個使用最多10%的CPU和50M的內存
• 如果停止運行立即重新啟動container
• 映射本地80端口到web的80端口
• 指導web的containers通過負載均衡網絡webnet共享80端口。(在內部，containers will publish to web’s port 80 at an ephemeral port)
• 使用默認設置定義webnet網絡

運行新的負債均衡的app

docker swarm init

# app name: getstartedlab
docker stack deploy -c docker-compose.yml getstartedlab

# See a list of the five containers you just launched
docker stack ps getstartedlab

Scale(規(guī)劃) the app

可以修改replicas，保存，重新運行docker stack deploy:

docker stack deploy -c docker-compose.yml getstartedlab

Docker will do an in-place update, no need to tear the stack down first or kill any containers.

摧毀app和swarm

docker stack rm getstartedlab

This removes the app, but our one-node swarm is still up and running (as shown by docker node ls). Take down the swarm with docker swarm leave --force.

docker stack ls              # List all running applications on this Docker host
docker stack deploy -c <composefile> <appname>  # Run the specified Compose file
docker stack services <appname>       # List the services associated with an app
docker stack ps <appname>   # List the running containers associated with an app
docker stack rm <appname>                             # Tear down an application