Docker Compose

It is a tool you can define and run multiple applications docker, you can use yaml file to configure your applications. Just perform a simple command can create it from the configuration and start all services.

Compose for all environments: production, continuous integration, development, testing and CI workflow

The use of three steps:

Need to install the docker, in order to use multiple running Dockerfile
In docker-compose composition as defined in the service application. So that they can run together in an isolated environment.
Running docker-compose upstart all your applications

Enter the following topic: how to install and deploy a simple application

Install Docker Compose（linux）

Docker Compose installation must be installed docker, details can refer to Get Started with Docker

# 下载
sudo curl -L "https://github.com/docker/compose/releases/download/1.23.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
# 授权
sudo chmod +x /usr/local/bin/docker-compose
# 查看版本
docker-compose --version

See the version information of the installation is successful

[root@localhost composetest]# docker-compose --version
docker-compose version 1.23.2, build 1110ad01

Building a simple application

Referring to the official website compose-demo
first create a project pathcomposetest

$ mkdir composetest
$ cd composetest

1 build python application

Create a named app.pyfile in your project path

import time

import redis
from flask import Flask


app = Flask(__name__)
cache = redis.Redis(host='redis', port=6379)


def get_hit_count():
    retries = 5
    while True:
        try:
            return cache.incr('hits')
        except redis.exceptions.ConnectionError as exc:
            if retries == 0:
                raise exc
            retries -= 1
            time.sleep(0.5)


@app.route('/')
def hello():
    count = get_hit_count()
    return 'Hello World! I have been seen {} times.\n'.format(count)

if __name__ == "__main__":
    app.run(host="0.0.0.0", debug=True)

File content is roughly: Set the default port 6379 host redis native, started redis connection and perform hello (), the output of visits to the page.

2 build Dockerfile file

Under the project to create a path Dockerfile, as follows

FROM python:3.4-alpine
ADD . /code
WORKDIR /code
RUN pip install -r requirements.txt
CMD ["python", "app.py"]

Roughly meaning:

Use base image Python 3.4
The image mapped to the current directory / code directory
Set the working directory is / code
Python installation dependencies
Start app.py program

There pit, use python-3.4 will build error

Fatal Python error: getentropy() failed
ERROR: Service 'web' failed to build: The command '/bin/sh -c pip install -r requirements.txt' returned a non-zero code: 139

Modify python python-3.5 version can be

3 Build docker-compose.yml file

Created in the current directorydocker-compose.yml

version: '3'
services:
  web:
    build: .
    ports:
     - "5000:5000"
  redis:
    image: "redis:alpine"

Compose a web service defines a two redis

Building web applications, built from Dockerfile in the current directory, and open port 5000
Use official redis image library, the default port 6379

This enables access 6379 python script, hits plus one.

4 run and build docker compose

carried out docker-compose up

Building web
Step 1/5 : FROM python:3.4-alpine3.8
3.4-alpine3.8: Pulling from library/python
c87736221ed0: Pull complete
c3f51b0d0765: Pull complete
e919dffdee54: Pull complete
f0766e77b512: Pull complete
bcf776216162: Pull complete
Digest: sha256:e88f2ce19bcabb986adb3a87b5effc7eaf5900b8d6049ffb85ca3dd59df0c466
Status: Downloaded newer image for python:3.4-alpine3.8
 ---> f6d3872c2a66
Step 2/5 : ADD . /code
 ---> 7a4e55428219
 ...
 Creating composetest_redis_1 ... done
Creating composetest_web_1   ... done
Attaching to composetest_web_1, composetest_redis_1

accesshttp://192.168.124.16:5000/
page

5 modify and add to mount compose.yml

Add bindings for web services

version: '3'
services:
  web:
    build: .
    ports:
     - "5000:5000"
    volumes:
     - .:/code
  redis:
    image: "redis:alpine"

6 Restart docker-compose

[root@localhost composetest]# docker-compose restart
Recreating composetest_web_1 ... done
Starting composetest_redis_1 ... done
Attaching to composetest_redis_1, composetest_web_1
redis_1  | 1:C 21 Mar 2019 02:38:38.862 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
redis_1  | 1:C 21 Mar 2019 02:38:38.862 # Redis version=5.0.4, bits=64, commit=00000000, modified=0, pid=1, just started
redis_1  | 1:C 21 Mar 2019 02:38:38.862 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf

7 Modify the application configuration

Modify app.py return information

return 'Hello Chen! I have been seen {} times.\n'.format(count)

Visit again
! [Insert Picture description here] (https://img-blog.csdnimg.cn/20190321111724948.png

8 Docker Compose commonly used commands

构建建启动nignx容器
docker-compose up -d nginx                     
登录到nginx容器中
docker-compose exec nginx bash            
删除所有nginx容器,镜像
docker-compose down                              
显示所有容器
docker-compose ps                                   
重新启动nginx容器
docker-compose restart nginx                   
在php-fpm中不启动关联容器，并容器执行php -v 执行完成后删除容器
docker-compose run --no-deps --rm php-fpm php -v  
构建镜像
docker-compose build nginx                         
不带缓存的构建
docker-compose build --no-cache nginx   
查看nginx的日志 
docker-compose logs  nginx                     
查看nginx的实时日志
docker-compose logs -f nginx                   

验证（docker-compose.yml）文件配置，当配置正确时，不输出任何内容，当文件配置错误，输出错误信息。 
docker-compose config  -q                        
以json的形式输出nginx的docker日志
docker-compose events --json nginx       
暂停nignx容器
docker-compose pause nginx                 
恢复ningx容器
docker-compose unpause nginx             
删除容器（删除前必须关闭容器）
docker-compose rm nginx                       
停止nignx容器
docker-compose stop nginx                    
启动nignx容器
docker-compose start nginx