Docker在多容器部署应用（18）

一、实验概述

分别创建部署两个容器flask-redis和redis，让容器flask-redis可以访问容器redis，并将5000映射至本地，进行访问。

二、实验步骤

1、上传app.py到/app目录下，以下为app.py的内容，实现通过访问5000端口，达到让redis显示记录访问次数的效果

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)

2、在/app目录下编辑Dockerfile文件

FROM python:2.7
LABEL maintaner="[e-mail]"
COPY . /app
WORKDIR /app
RUN pip install flask redis
EXPOSE 5000
CMD [ "python", "app.py" ]

3、build镜像

[[e-mail] app]# docker build -t zheng/flask-redis .

4、创建redis容器,其默认端口是6379，不用-p进行端口暴露

[[e-mail] app]# docker run -d --name redis redis
ba1f8a2e37ec703cc8f849a6d5bd0b26d0c83989444338683d89299a87c24d0b
[[e-mail] app]# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED            
 STATUS              PORTS               NAMESba1f8a2e37ec        redis               "docker-entrypoint.s…"   11 seconds ago    
  Up 9 seconds        6379/tcp            redis

5、创建容器flask-redis，并且link到容器redis进行通信，传递 REDIS_HOST=re
dis的环境变量

[[e-mail] app]# docker run -d --name flask-redis --link redis -e REDIS_HOST=re
dis zheng/flask-redis

6、进入容器flask-redis，即可访问5000端口

[[e-mail] app]# docker exec -it flask-redis /bin/sh
# ping redis
PING redis (172.17.0.2) 56(84) bytes of data.
64 bytes from redis (172.17.0.2): icmp_seq=1 ttl=64 time=0.104 ms
64 bytes from redis (172.17.0.2): icmp_seq=2 ttl=64 time=0.156 ms
64 bytes from redis (172.17.0.2): icmp_seq=3 ttl=64 time=0.144 ms
--- redis ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1999ms
rtt min/avg/max/mdev = 0.104/0.134/0.156/0.025 ms
# curl 127.0.0.1:5000
Hello Container World! I have been seen 1 times and my hostname is ee04b54f304e.
# curl 127.0.0.1:5000 
Hello Container World! I have been seen 2 times and my hostname is ee04b54f304e.
# exit

7、将5000端口映射到本地，宿主机本地便可访问5000端口

[[e-mail] app]# docker stop flask-redis 
flask-redis
[[e-mail] app]# docker rm flask-redis 
flask-redis
[[e-mail] app]# docker run -d --name flask-redis --link redis -e REDIS_HOST=re
dis -p 5000:5000 zheng/flask-redis922122ac6ec6eeb38ee8de093ffebc922a008f24432b00d8f893345afdd9bc03
[[e-mail] app]# curl 127.0.0.1:5000
Hello Container World! I have been seen 3 times and my hostname is 922122ac6ec6.
[[e-mail] app]# curl 127.0.0.1:5000
Hello Container World! I have been seen 4 times and my hostname is 922122ac6ec6.