Docker Compose 使用方法
Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a Compose file to configure your application’s services. Then, using a single command, you create and start all the services from your configuration.
Dockerfile 可以讓用戶管理一個單獨的應用容器；而 Compose 則允許用戶在一個模板（YAML 格式）中定義一組相關聯的應用容器（被稱為一個 project，即項目），例如一個 Web 服務容器再加上后端的數據庫服務容器等，就拿官網的 Python 例子來說，功能很簡單，利用 redis 的 incr 的功能對頁面的訪問量進行統計。
docker-compose 的安裝可以參考官網，如果安裝了 Docker for Mac 或者 Docker for windows 則直接就存在了。
創建項目目錄:
$ mkdir composetest
$ cd composetest
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創建 Python 的程序 app.py ，功能就是利用 redis 的 incr 方法進行訪問計數。
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)
由于 Python 依賴的 flask 、 redis 組件都需要另外安裝，比如使用 pip 來安裝，單獨設置一文件 requirements.txt ，內容如下:
flask
redis
創建 service 依賴的第一個 image， app.py 程序的運行環境，利用 Dockerfile 來制作，內容如下:
FROM python:2.7 #基于 python:2.7 鏡像
ADD . /code #將本地目錄中的內容添加到 container 的 /code 目錄下
WORKDIR /code #設置程序工作目錄為 /code
RUN pip install -r requirements.txt #運行安裝命令
CMD python app.py #啟動程序
Dockerfile 創建好就可以制作鏡像了，運行 docker build -t compose/python_app . ，成功后通過 docker images 查看即能看到:
docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
compose/python_app latest 1a92fed00abd 59 minutes ago 680.4 MB
接下來制作 docker-compose 需要的配置文件 docker-compose.yml ， version 要選擇 2 ，1的版本很古老了，配置中可以看到創建了 2 個 service， web 和 redis ，各自有依賴的鏡像，其中 web 開放 container 的5000端口，并與 host 的5000端口應對，方便通過 localhost:5000 來訪問， volumes 即將本地目錄中的文件加載到容器的 /code 中， depends_on 表名 services web 是依賴另一個 service redis 的，完整的配置如下:
version: '2'
services:
web:
image: compose/python_app
ports:
- "5000:5000"
volumes:
- .:/code
depends_on:
- redis
redis:
image: redis
前提都搞定了，就差最后一步啟動了，命令 docker-compose up ，成功后如下:
Attaching to composetestbypython_redis_1
redis_1 | 1:C 04 Nov 10:35:17.448 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
redis_1 | _._
redis_1 | _.-``__ ''-._
redis_1 | _.-`` `. `_. ''-._ Redis 3.2.5 (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 04 Nov 10:35:17.450 # 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 04 Nov 10:35:17.450 # Server started, Redis version 3.2.5
redis_1 | 1:M 04 Nov 10:35:17.451 # 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 04 Nov 10:35:17.451 # 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 04 Nov 10:35:17.451 * The server is now ready to accept connections on port 6379
此時通過compose 的 ps 命令也能看到 docker-compose ps :
docker-compose ps
Name Command State Ports
---------------------------------------------------------------------------------------------
composetestbypython_redis_1 docker-entrypoint.sh redis ... Up 6379/tcp
composetestbypython_web_1 /bin/sh -c python app.py Up 0.0.0.0:5000->5000/tcp
ok ，在瀏覽器中訪問 http://localhost:5000 就能看到最終的樣子啦。
{% qnimg docker/2016-11-04-22-40-11.jpg title: alt: 'class:' %}
docker-compose 還有很多實用的命令，比如 logs、build、start、stop 等，可以通過 docker-compose --help 來查看:
Define and run multi-container applications with Docker.
Usage:
docker-compose [-f <arg>...] [options] [COMMAND] [ARGS...]
docker-compose -h|--help
Options:
-f, --file FILE Specify an alternate compose file (default: docker-compose.yml)
-p, --project-name NAME Specify an alternate project name (default: directory name)
--verbose Show more output
-v, --version Print version and exit
-H, --host HOST Daemon socket to connect to
--tls Use TLS; implied by --tlsverify
--tlscacert CA_PATH Trust certs signed only by this CA
--tlscert CLIENT_CERT_PATH Path to TLS certificate file
--tlskey TLS_KEY_PATH Path to TLS key file
--tlsverify Use TLS and verify the remote
--skip-hostname-check Don't check the daemon's hostname against the name specified
in the client certificate (for example if your docker host
is an IP address)
Commands:
build Build or rebuild services
bundle Generate a Docker bundle from the Compose file
config Validate and view the compose file
create Create services
down Stop and remove containers, networks, images, and volumes
events Receive real time events from containers
exec Execute a command in a running container
help Get help on a command
kill Kill containers
logs View output from containers
pause Pause services
port Print the public port for a port binding
ps List containers
pull Pulls service images
push Push service images
restart Restart services
rm Remove stopped containers
run Run a one-off command
scale Set number of containers for a service
start Start services
stop Stop services
unpause Unpause services
up Create and start containers
version Show the Docker-Compose version information
來自：https://segmentfault.com/a/1190000007429156