04-容器编排docker-compose

一、概念：

通过service创建container的方式有两种：第一种是从官网拉取镜像，第二种是本地build

二：安装和实验

docker-compose 命令：

官网安装：
https://docs.docker.com/compose/install/

命令使用：
默认识别本地docker-compose.yml文件并执行(-d 代表后台执行)
docker-compose up -d

指定compose文件
docker-compose -f my-docker-compose.yml up-d

这里我们启动一个yaml文件：

vim docker-compose.yml

version: '3'

services:

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

  mysql:
    image: mysql:5.7
    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

当前目录启动：

docker-compose up -d

执行会默认创建一个网络环境和container

查看镜像：

docker-compose images

查看容器：

docker-compose ps

停止容器：

docker-compose stop

运行容器：

docker-compose start

删除yml文件中的容器：

docker-compose down

进入container(名字是yml文件中的service名字)：

docker-compose exec wordpress bash

docker-compose使用docker build方式启动一个容器

创建一个目录

app.py

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

FROM python:2.7
LABEL maintaner="lijiahao928611@gmail.com"
COPY . /app
WORKDIR /app
RUN pip install flask redis
EXPOSE 5000
CMD [ "python", "app.py" ]

docker-compse-yml

version: "3"

services:

  redis:
    image: redis

  web:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - 8080:5000
    environment:
      REDIS_HOST: redis

docker build -t .

docker-compose up -d

水平扩展和负载均衡

水平扩展：

vi docker-compse-yml

删除这两行：

docker-compose up --scale web=3 -d

实战一：测试web

app.py

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)

Dockerfile

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" ]

docker-compose.yml

version: "3"

services:

  redis:
    image: redis

  web:
    build:
      context: .
      dockerfile: Dockerfile
    ports: ["8080"]
    environment:
      REDIS_HOST: redis

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

docker-compose up