第一步：创建一个应用目录(后面使用该目录为工作目录，存放应用文件以及Dockerfile)：
mkdir /root/docker/lzwtestpython cd /root/docker/lzwtestpython
第二步：为容器定义一个Dockerfile：
创建Dockerfile文件：
vi Dockerfile
输入Dockerfile文件内容：
# Use an official Python runtime as a parent image FROM python:2.7-slim # Set the working directory to /app WORKDIR /app # Copy the current directory contents into the container at /app COPY . /app # Install any needed packages specified in requirements.txt RUN pip install --trusted-host pypi.python.org -r requirements.txt # Make port 80 available to the world outside this container EXPOSE 80 # Define environment variable ENV NAME World # Run app.py when the container launches CMD ["python", "app.py"]
在文件内容中，我们可以看到，我们的python文件为app.py，下面我们需要去创建这个文件。一般来说,python项目中会包含一个 requirements.txt 文件,用于记录所有依赖包。
第三步：创建requirements.txt和app.py
创建requirements.txt文件：
vi requirements.txt
输入requirements.txt文件内容：
Flask Redis
创建app.py文件：
vi app.py
输入app.py文件内容：
from flask import Flask from redis import Redis, RedisError import os import socket # Connect to Redis redis = Redis(host="redis", db=0, socket_connect_timeout=2, socket_timeout=2) app = Flask(__name__) @app.route("/") def hello(): try: visits = redis.incr("counter") except RedisError: visits = "<i>cannot connect to Redis, counter disabled</i>" html = "<h3>Hello {name}!</h3>" \ "<b>Hostname:</b> {hostname}<br/>" \ "<b>Visits:</b> {visits}" return html.format(name=os.getenv("NAME", "world"), hostname=socket.gethostname(), visits=visits) if __name__ == "__main__": app.run(host='0.0.0.0', port=80)
到这里，我们可以发现，我们没有真正的在电脑上安装python,和requirements.txt里提到的flask或者redis。看起来，你并没有搭建好python+flask+redis的环境。但是，通过接下来的步骤，你即将拥有。
第四步：创建应用
检查工作文件夹下的三个文件是否都创建完成，三个文件如下：
$ ls Dockerfile app.py requirements.txt
现在开始运行创建Docker镜像命令，我们加上-t命令来命名，这里我们起一个很友好的名字friendlyhello（^_^）
docker build -t friendlyhello .
我们可以看一看执行的命令的回显：
Sending build context to Docker daemon 4.608kB Step 1/7 : FROM python:2.7-slim 2.7-slim: Pulling from library/python 802b00ed6f79: Pull complete 10b2d5f7ed73: Pull complete 1073a127cf89: Pull complete 90283f3dc1cd: Pull complete Digest: sha256:0a43a6d7858af4a42427c792b682936d2cd34e183fb026627f53ddb556d4bf62 Status: Downloaded newer image for python:2.7-slim ---> c9cde4658340 Step 2/7 : WORKDIR /app ---> Running in 5b6e0800c538 Removing intermediate container 5b6e0800c538 ---> 3ac183b809ce Step 3/7 : COPY . /app ---> b05ac52c77de Step 4/7 : RUN pip install --trusted-host pypi.python.org -r requirements.txt ---> Running in 58bd2a10311e Collecting Flask (from -r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/7f/e7/08578774ed4536d3242b14dacb4696386634607af824ea997202cd0edb4b/Flask-1.0.2-py2.py3-none-any.whl (91kB) Collecting Redis (from -r requirements.txt (line 2)) Downloading https://files.pythonhosted.org/packages/3b/f6/7a76333cf0b9251ecf49efff635015171843d9b977e4ffcf59f9c4428052/redis-2.10.6-py2.py3-none-any.whl (64kB) Collecting itsdangerous>=0.24 (from Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/dc/b4/a60bcdba945c00f6d608d8975131ab3f25b22f2bcfe1dab221165194b2d4/itsdangerous-0.24.tar.gz (46kB) Collecting Jinja2>=2.10 (from Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/7f/ff/ae64bacdfc95f27a016a7bed8e8686763ba4d277a78ca76f32659220a731/Jinja2-2.10-py2.py3-none-any.whl (126kB) Collecting Werkzeug>=0.14 (from Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/20/c4/12e3e56473e52375aa29c4764e70d1b8f3efa6682bef8d0aae04fe335243/Werkzeug-0.14.1-py2.py3-none-any.whl (322kB) Collecting click>=5.1 (from Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/fa/37/45185cb5abbc30d7257104c434fe0b07e5a195a6847506c074527aa599ec/Click-7.0-py2.py3-none-any.whl (81kB) Collecting MarkupSafe>=0.23 (from Jinja2>=2.10->Flask->-r requirements.txt (line 1)) Downloading https://files.pythonhosted.org/packages/4d/de/32d741db316d8fdb7680822dd37001ef7a448255de9699ab4bfcbdf4172b/MarkupSafe-1.0.tar.gz Building wheels for collected packages: itsdangerous, MarkupSafe Running setup.py bdist_wheel for itsdangerous: started Running setup.py bdist_wheel for itsdangerous: finished with status 'done' Stored in directory: /root/.cache/pip/wheels/2c/4a/61/5599631c1554768c6290b08c02c72d7317910374ca602ff1e5 Running setup.py bdist_wheel for MarkupSafe: started Running setup.py bdist_wheel for MarkupSafe: finished with status 'done' Stored in directory: /root/.cache/pip/wheels/33/56/20/ebe49a5c612fffe1c5a632146b16596f9e64676768661e4e46 Successfully built itsdangerous MarkupSafe Installing collected packages: itsdangerous, MarkupSafe, Jinja2, Werkzeug, click, Flask, Redis Successfully installed Flask-1.0.2 Jinja2-2.10 MarkupSafe-1.0 Redis-2.10.6 Werkzeug-0.14.1 click-7.0 itsdangerous-0.24 Removing intermediate container 58bd2a10311e ---> 20b7d92b6075 Step 5/7 : EXPOSE 80 ---> Running in 45f7bfcee8c8 Removing intermediate container 45f7bfcee8c8 ---> 0c99f24bb0ca Step 6/7 : ENV NAME World ---> Running in 4d192a73ee76 Removing intermediate container 4d192a73ee76 ---> da526dcf3514 Step 7/7 : CMD ["python", "app.py"] ---> Running in 50226d88c2d5 Removing intermediate container 50226d88c2d5 ---> bb0d475e1b3c Successfully built bb0d475e1b3c Successfully tagged friendlyhello:latest
分析回显，我们可以看到执行的过程有7步：
Step 1/7 : FROM python:2.7-slim Step 2/7 : WORKDIR /app Step 3/7 : COPY . /app Step 4/7 : RUN pip install --trusted-host pypi.python.org -r requirements.txt Step 5/7 : EXPOSE 80 Step 6/7 : ENV NAME World Step 7/7 : CMD ["python", "app.py"]
这7步，是在Dockerfile里指定的(所以Dockerfile最关键啊#_#)。
命令执行完后，我们可以输入如下命令来查看本机安装的docker 镜像
$ docker image ls REPOSITORY TAG IMAGE ID friendlyhello latest 326387cea398第五步
第五步：运行应用
运行应用，并且把你物理机（或者云服务器）的4000端口映射到我们容器的80端口，使用-p命令：
docker run -p 4000:80 friendlyhello
哈？你问为什么要这样做？因为你的app.py文件里指的是80端口，如果我们没有使用docker,直接是在自己电脑上运行该python程序，确实可以通过http://0.0.0.0:80进行访问。目前在我们的容器中，确实也是80端口启用了，但是要让我们的其他用户访问这台物理机地址的容器内的python应用，需要把物理机的端口4000与容器的80端口进行映射。现在，请用http://localhost:4000 来检查一下吧
如果你是布置在别的机器上而非本机的话，也可以用地址加端口号的方式来访问。例如http://192.168.99.100:4000/ 或者http://www.yinyubo.cn:4000/
没有浏览器的话，也可以通过curl命令工具来访问
$ curl http://localhost:4000 <h3>Hello World!</h3><b>Hostname:</b> 8fc990912a14<br/><b>Visits:</b> <i>cannot connect to Redis, counter disabled</i>
如果你需要关闭docker应用的话，可以用如下方法：
$ docker container ls CONTAINER ID IMAGE COMMAND CREATED 1fa4ab2cf395 friendlyhello "python app.py" 28 seconds ago
先获得docker 容器的ID，然后用docker container stop 命令来关闭它，例如：
docker container stop 1fa4ab2cf395
