docker-compose入门

docker-compose适合本地搭建开发环境，生产环境多用swam或者k8s。

docker-compose：本地启动多个容器，即一个应用要用的python前端、java后端、数据库等，每个功能一个container，docker-compose可以一次启动完成，另外他还可以利用scale选项进行负载均衡。

例子一：docker-compose一键启动wordpress

docker-compose

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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

浏览器访问：http://172.16.241.131:8080

不出意外会出错：

Error establishing a database connection

认证方法错误，mysql8.0以后默认的认证方式改了，所以才会有这样的错误

解决方法

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#进入mysql容器 docker-compose exec mysql bash #登陆数据库 mysql -u root -p use mysql; #开启root远程访问权限 grant all on *.* to 'root'@'%'; #修改加密规则 alter user 'root'@'localhost' identified by '123456' password expire never; #更新密码 alter user 'root'@'%' identified with mysql_native_password by '123456'; #刷新权限 flush privileges;

再次刷新浏览器就好了

例子二：使用scale负载均衡

docker-compose

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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

　　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)

　　

进入docker-compose.yml所在文件夹，启动docker-compose

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1	docker-compose up　--scale web=3 -d

 查看是否进行了容器扩展与负载均衡

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[root@localhost scale]# docker ps CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS                                     NAMES db5de6922ea8        dockercloud/haproxy   "/sbin/tini -- docke…"   56 minutes ago      Up 56 minutes       443/tcp, 1936/tcp, 0.0.0.0:8080->80/tcp   scale_lb_1 7061e5a0a6d6        scale_web             "python app.py"          56 minutes ago      Up 56 minutes       80/tcp                                    scale_web_3 829a6dc26957        scale_web             "python app.py"          56 minutes ago      Up 56 minutes       80/tcp                                    scale_web_1 b61dc8fe1846        redis                 "docker-entrypoint.s…"   56 minutes ago      Up 56 minutes       6379/tcp                                  scale_redis_1 9b97567cfcf7        scale_web             "python app.py"          56 minutes ago      Up 56 minutes       80/tcp                                    scale_web_2   [root@localhost scale]# for i in `seq 10`; do curl 172.16.241.132:8080; done  Hello Container World! I have been seen 1 times and my hostname is 829a6dc26957. Hello Container World! I have been seen 2 times and my hostname is 9b97567cfcf7. Hello Container World! I have been seen 3 times and my hostname is 7061e5a0a6d6. Hello Container World! I have been seen 4 times and my hostname is 829a6dc26957. Hello Container World! I have been seen 5 times and my hostname is 9b97567cfcf7. Hello Container World! I have been seen 6 times and my hostname is 7061e5a0a6d6. Hello Container World! I have been seen 7 times and my hostname is 829a6dc26957. Hello Container World! I have been seen 8 times and my hostname is 9b97567cfcf7. Hello Container World! I have been seen 9 times and my hostname is 7061e5a0a6d6. Hello Container World! I have been seen 10 times and my hostname is 829a6dc26957.

　　

例子三：python、java、PGdatabase多模块利用docker-compose一键启动