docker深入2-体验compose
2016/6/23
一、示例
测试环境基于文档：docker深入2-熟悉v1.11和找不同.txt
目标：熟悉 docker compose 的使用。
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---------------------- n36.test ----------------------
docker-compose -> yml -> services -> p_w_picpaths(web+redis)
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二、配置
1、安装 docker-compose
参考页面：https://github.com/docker/compose/releases
curl -L https://github.com/docker/compose/releases/download/1.7.1/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose
chmod +x /usr/local/bin/docker-compose
2、测试
[Jack@n36 ~]$ docker-compose --version
docker-compose version 1.7.1, build 0a9ab35
三、初体验
1、配置一个应用
[Jack@n36 ~]$ mkdir /data/docker/compose-test
[Jack@n36 ~]$ cd /data/docker/compose-test/
使用 flask+redis 建立一个简单的web页面。
[Jack@n36 compose-test]$ cat app.py
from flask import Flask
from redis import Redis
app = Flask(__name__)
redis = Redis(host='redis', port=6379)
@app.route('/')
def hello():
redis.incr('hits')
return 'Hello World! I have been seen %s times.' % redis.get('hits')
if __name__ == "__main__":
app.run(host="0.0.0.0", debug=True)
该应用的依赖：
[Jack@n36 compose-test]$ cat requirements.txt
flask
redis
2、准备镜像
1）编写 dockerfile 来构建镜像 “web”
[Jack@n36 compose-test]$ cat Dockerfile
FROM python:2.7
ADD . /code
WORKDIR /code
RUN pip install -r requirements.txt
CMD python app.py
[Jack@n36 compose-test]$ docker build -t web .
2、从仓库拉取“redis”镜像
[Jack@n36 compose-test]$ docker pull redis
3、定义服务
[Jack@n36 compose-test]$ cat docker-compose.yml
version: '2'
services:
web:
p_w_picpath: web
ports:
- "5000:5000"
volumes:
- .:/code
depends_on:
- redis
redis:
p_w_picpath: redis
镜像 web 来自上一步构建
镜像 redis 来自仓库，已经提前准备好
（当然了，web镜像也可以当场 build，redis镜像也可以当场 pull，看需求决定。）
4、启动
[Jack@n36 compose-test]$ docker-compose up
Creating composetest_redis_1
Creating composetest_web_1
Attaching to composetest_redis_1, composetest_web_1
redis_1 | _._
redis_1 | _.-``__ ''-._
redis_1 | _.-`` `. `_. ''-._ Redis 3.2.1 (00000000/0) 64 bit
redis_1 | .-`` .-```. ```\/ _.,_ ''-._
redis_1 | ( ' , .-` | `, ) Running in standalone mode
redis_1 | |`-._`-...-` __...-.``-._|'` _.-'| Port: 6379
redis_1 | | `-._ `._ / _.-' | PID: 1
redis_1 | `-._ `-._ `-./ _.-' _.-'
redis_1 | |`-._`-._ `-.__.-' _.-'_.-'|
redis_1 | | `-._`-._ _.-'_.-' | http://redis.io
redis_1 | `-._ `-._`-.__.-'_.-' _.-'
redis_1 | |`-._`-._ `-.__.-' _.-'_.-'|
redis_1 | | `-._`-._ _.-'_.-' |
redis_1 | `-._ `-._`-.__.-'_.-' _.-'
redis_1 | `-._ `-.__.-' _.-'
redis_1 | `-._ _.-'
redis_1 | `-.__.-'
redis_1 |
redis_1 | 1:M 23 Jun 07:29:38.855 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
redis_1 | 1:M 23 Jun 07:29:38.855 # Server started, Redis version 3.2.1
redis_1 | 1:M 23 Jun 07:29:38.855 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
redis_1 | 1:M 23 Jun 07:29:38.855 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
redis_1 | 1:M 23 Jun 07:29:38.855 * The server is now ready to accept connections on port 6379
web_1 | * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
web_1 | * Restarting with stat
web_1 | * Debugger is active!
web_1 | * Debugger pin code: 621-396-368
web_1 | 172.20.0.1 - - [23/Jun/2016 07:29:52] "GET / HTTP/1.1" 200 -
web_1 | 172.20.0.1 - - [23/Jun/2016 07:29:53] "GET / HTTP/1.1" 200 -
web_1 | 172.20.0.1 - - [23/Jun/2016 07:29:53] "GET / HTTP/1.1" 200 -
web_1 | 172.20.0.1 - - [23/Jun/2016 07:29:54] "GET / HTTP/1.1" 200 -
web_1 | 172.20.0.1 - - [23/Jun/2016 07:29:54] "GET / HTTP/1.1" 200 -
web_1 | 172.20.0.1 - - [23/Jun/2016 07:29:55] "GET / HTTP/1.1" 200 -
5、在另一个窗口来测试
[Jack@n36 compose-test]$ docker ps -a -f name=compose
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
9decfef8566b web "/bin/sh -c 'python a" 2 minutes ago Up 2 seconds 0.0.0.0:5000->5000/tcp composetest_web_1
eebf07d7c102 redis "docker-entrypoint.sh" 2 minutes ago Up 2 seconds 6379/tcp composetest_redis_1
请求：
[Jack@n36 ~]$ curl 127.0.0.1:5000
Hello World! I have been seen 1 times.[Jack@n36 ~]$ curl 127.0.0.1:5000
Hello World! I have been seen 2 times.[Jack@n36 ~]$ curl 127.0.0.1:5000
Hello World! I have been seen 3 times.[Jack@n36 ~]$ curl 127.0.0.1:5000
Hello World! I have been seen 4 times.[Jack@n36 ~]$ curl 127.0.0.1:5000
Hello World! I have been seen 5 times.[Jack@n36 ~]$ curl 127.0.0.1:5000
Hello World! I have been seen 6 times.[Jack@n36 ~]$
符合预期。
6、其他命令
1）后台运行
[Jack@n36 compose-test]$ docker-compose up -d
2）任务管理
[Jack@n36 compose-test]$ docker-compose ps
Name Command State Ports
-------------------------------------------------------------------------------------
composetest_redis_1 docker-entrypoint.sh redis ... Up 6379/tcp
composetest_web_1 /bin/sh -c python app.py Up 0.0.0.0:5000->5000/tcp
3）执行一次性的命令
[Jack@n36 compose-test]$ docker-compose run web env
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=cc7a996c06da
TERM=xterm
LANG=C.UTF-8
GPG_KEY=C01E1CAD5EA2C4F0B8E3571504C367C218ADD4FF
PYTHON_VERSION=2.7.11
PYTHON_PIP_VERSION=8.1.2
HOME=/root
[Jack@n36 compose-test]$ docker-compose run web ip a |grep global
inet 172.20.0.4/16 scope global eth0
4）停止服务
[Jack@n36 compose-test]$ docker-compose stop
Stopping composetest_web_1 ... done
Stopping composetest_redis_1 ... done
四、小结
1、安装 docker-compose
2、准备镜像
3、准备yml文件，定义好服务之间的依赖
4、使用 docker-compose 来启动服务
官网 docs 上还有一些示例，后续实验一下。
ZYXW、参考
1、docs
https://docs.docker.com/compose/install/
https://docs.docker.com/compose/gettingstarted/
