docker-compose

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Docker 的批处理，它可以通过一个 yml 文件定义多容器的 docker 应用，通过一条命令就可以根据 yml 文件的定义取创建或者管理多个容器。`docker-compose.yml`

基本命令及安装

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docker-compose --verison
# linux
sudo curl -L https://github.com/docker/compose/releases/download/1.21.2/docker-compose-$(uname -s)-$(uname -m) -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose

# 启动
docker-compose up
docker-compose up -d # 后台
docker-compose -f docker-compose.yml up
docker-compose images
docker-compose down

部署一个 WordPress

详细文档查看官方hub

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# 启动一个 mysql container
docker run -d --name mysql -v mysql-data://var/lib/mysql -e MYSQL_ROOT_PASSWORD=root -e MYSQL_DATABASE=wordpress mysql
# 启动 wordpress container
docker run -d -e WORDPRESS_DB_HOST=mysql:3306 --link mysql -p 8080:80 wordpress

docker-compose.yml

概念

  • Services
  • Networks
  • Volumes

Services

一个Service代表一个container，这个container可以从dockerhub的image来创建，或者从本地的Dockerfile`build出来的image`来创建

Service的启动类似的docker run，我们可以给其指定network和volume，所以可以给service指定network和Volume的引用

wordpress example

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version: '3'

services:

  wordpress:
    image: wordpress
    ports:
      - 8080:80
    environment:
      WORDPRESS_DB_HOST: mysql
      WORDPRESS_DB_PASSWORD: root
    networks:
      - my-bridge

  mysql:
    image: mysql
    environment:
      MYSQL_ROOT_PASSWORD: root
      MYSQL_DATABASE: wordpress
    volumes:
      - mysql-data:/var/lib/mysql
    networks:
      - my-bridge

volumes:
  mysql-data:

networks:
  my-bridge:
    driver: bridge

flask-redis example

  • docker-compose.yml
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version: "3"

services:

  redis:
    image: redis

  web:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - 8080:5000
    environment:
      REDIS_HOST: redis
  • app.py
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from flask import Flask
from redis import Redis
import os
import socket

app = Flask(__name__)
redis = Redis(host=os.environ.get('REDIS_HOST', '127.0.0.1'), port=6379)


@app.route('/')
def hello():
    redis.incr('hits')
    return 'Hello Container World! I have been seen %s times and my hostname is %s.\n' % (redis.get('hits'),socket.gethostname())


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, debug=True)
  • Dockerfile
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FROM python:2.7
LABEL maintaner="Peng Xiao xiaoquwl@gmail.com"
COPY . /app
WORKDIR /app
RUN pip install flask redis
EXPOSE 5000
CMD [ "python", "app.py" ]

扩展+负载均衡

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docker-compose up --scale web=3 -d
# 后端运行三台 web container，可以随便扩展
# 在上面的 flask 中会因为 ports 不能重复利率用二报错 删掉即可
  • Dockerfile
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FROM python:2.7
LABEL maintaner="Peng Xiao xiaoquwl@gmail.com"
COPY . /app
WORKDIR /app
RUN pip install flask redis
EXPOSE 80
CMD [ "python", "app.py" ]
  • app.py
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from flask import Flask
from redis import Redis
import os
import socket

app = Flask(__name__)
redis = Redis(host=os.environ.get('REDIS_HOST', '127.0.0.1'), port=6379)


@app.route('/')
def hello():
    redis.incr('hits')
    return 'Hello Container World! I have been seen %s times and my hostname is %s.\n' % (redis.get('hits'),socket.gethostname())


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=80, debug=True)
  • docker-compose.yml
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version: "3"

services:

  redis:
    image: redis

  web:
    build:
      context: .
      dockerfile: Dockerfile
    environment:
      REDIS_HOST: redis

  lb:
    image: dockercloud/haproxy
    links:
      - web
    ports:
      - 8080:80
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

run

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docker-compose up -d
docker-compose ps
curl 127.0.0.1:8080
dcoker-compose up --scale web=3 -d  # 运行 3 个在后台
docker-compose ps
curl 127.0.0.1:8080 # 多 run 几次
curl 127.0.0.1:8080
Hello Container World! I have been seen 3 times and my hostname is 54389c4f203a.
curl 127.0.0.1:8080
Hello Container World! I have been seen 4 times and my hostname is 121e4d6e88db.
curl 127.0.0.1:8080
Hello Container World! I have been seen 5 times and my hostname is 6d2929bbaae4.

部署复杂的应用

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docker-compose build