Win10内置Ubuntu，完美使用Docker in Windows

Windows10 内置了Linux系统：WSL (Windows Subsystem for Linux, 又称Bash for Windows)。可以方便地在Win10里使用Ubuntu等Linux系统的命令行

Win10可以直接安装Docker in Windows，不需要像Win7一样，要配合VirtualBox。

Ref: https://nickjanetakis.com/blog/setting-up-docker-for-windows-and-wsl-to-work-flawlessly

关键字：Win10 Ubuntu18 WSL Docker “remote Docker daemon”

问题：
- WSL如何完美配合Docker使用呢？难道一定要通过VirtualBox么？或者一定要安装单独的Ubuntu系统么？
- 答案：很简单，通过remote Docker daemon连接！
优点：
- Docker基本无性能损失
- 无须另外安装VirtualBox等虚拟机
- 方便同时使用Win10、Ubuntu两个系统

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框架

Win10 + Docker <-- 本机共享文件夹Volume --> Ubuntu命令行(in WSL)
Ubuntu --> remote Docker daemon --> Docker in Windows
Win10浏览器 --> Docker in Windows --> Ubuntu IP --> Ubuntu内服务

步骤

1. 安装Docker in Windows10

官网：https://docs.docker.com/docker-for-windows/install/
打开Docker Desktop设置:
确保勾选：Expose daemon on localhost:2375 without TLS

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2. 在Win10 WSL里安装Ubuntu

这教程太多了，自行搜索。大致是打开虚拟化HyperV，安装Windows Feature: WSL，重启，微软商店里安装“Ubuntu18.04”

image.png
安装完毕，通过开始菜单 - Ubuntu打开，设置Linux用户名/密码
Win+R - “Bash”也能打开，注意跟上一步起始目录的区别

3. Ubuntu18安装Docker CE

官网：https://docs.docker.com/install/linux/docker-ce/ubuntu/
授于当前用户以root权限运行Docker CLI

# Allow your user to access the Docker CLI without needing root access.
sudo usermod -aG docker $USER

安装Docker Compose

# Install Python and PIP.
sudo apt-get install -y python3 python3-pip

# Install Docker Compose into your user's home directory.
pip install --user docker-compose

4. 连接Docker daemon

最关键的一行命令，打开Bash：

echo "export DOCKER_HOST=tcp://localhost:2375" >> ~/.bashrc && source ~/.bashrc

不通过deamon连接的话，你在Ubuntu里运行docker，就会出现错误：

docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

验证Docker启动成功：

docker info
docker-compose --version

kevinqq@CN:/mnt/c/Users/xxx$ docker run hello-world

Hello from Docker!
This message shows that your installation appears to be working correctly.

至此，已经在WSL Ubuntu里完美配置Docker成功了！

5. 进阶：使用Docker开发时要注意Win10共享文件夹的问题

Docker in Window里，只允许访问c:\Users\<id>\目录下的东西，Win+R - Bash打开时，默认目录也是这个文件夹

WSL Ubuntu18里，默认映射Win C盘为/mnt/c/，需要手动改为/c/

# Running Windows 10 17.09?
sudo mkdir /c
sudo mount --bind /mnt/c /c

测试一下docker-compose一个Flask网站：
https://docs.docker.com/compose/gettingstarted/

kevinqq@CN-00009841:/c/Users/xxx/git$ git clone https://github.com/kevinqqnj/docker-compose-starter.git
kevinqq@CN-00009841:/c/Users/xxx/git$ cd docker-compose-starter 
kevinqq@CN-00009841:/c/Users/xxx/git/docker-compose-starter$ docker-compose up --build
Building web
Step 1/5 : FROM python:3.6-alpine
 ---> 1837080c5e87
Step 2/5 : ADD . /code
 ---> Using cache
 ---> 1c28f8605b6f
Step 3/5 : WORKDIR /code
 ---> Using cache
 ---> 3b36663d505b
Step 4/5 : RUN pip install -r requirements.txt
 ---> Using cache
 ---> 5af3cbe591d4
Step 5/5 : CMD ["python", "app.py"]
 ---> Using cache
 ---> cf356692af43
Successfully built cf356692af43
Successfully tagged docker-compose-starter_web:latest
Starting docker-compose-starter_redis_1 ... done
Starting docker-compose-starter_web_1   ... done
Attaching to docker-compose-starter_web_1, docker-compose-starter_redis_1
...
redis_1  | 1:M 13 Jan 2019 07:45:08.470 * Ready to accept connections
web_1    |  * Serving Flask app "app" (lazy loading)
web_1    |  * Environment: production
web_1    |    WARNING: Do not use the development server in a production environment.
web_1    |    Use a production WSGI server instead.
web_1    |  * Debug mode: on
web_1    |  * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

此时，在Ubuntun里命令行访问，已经OK了：

kevinqq@CN-00009841:/c/Users/xxx$ curl http://localhost:5000
Hello World! I have been seen 1 times.
kevinqq@CN-00009841:/c/Users/xxx$ curl http://localhost:5000
Hello World! I have been seen 2 times.
kevinqq@CN-00009841:/c/Users/xxx$ curl http://localhost:5000
Hello World! I have been seen 3 times.

在Win10里访问localhost是不行的，需要先查看Ubuntu IP地址：

kevinqq@CN-00009841:/c/Users/xxx$ ifconfig eth1
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.21.96.1  netmask 255.255.255.240  broadcast 172.21.96.15

打开Win10浏览器，输入172.21.96.1:5000就看到Docker里的服务正常运行了：

下一篇：用docker启动一个Sanic微服务框架（TBD）https://github.com/kevinqqnj/sanic-ms