#Quickly SSH into a Docker container #如何用SSH快速登录Docker容器
I’ve been playing around with Docker for a few months and it’s great. 玩了几个月的Docker，发现这东西实在太棒了！
One thing that is slightly rage-inducing when using docker is having to SSH into a container. Generally if you have multiple containers that run sshd, you’ll want the SSH ports to be generated randomly to prevent conflicts. Connecting via SSH is slightly tedious to do in this case, as there are several steps involved. 但是Docker有时令人有点儿抓狂，那就是每次使用Docker，都必须通过SSH登陆到Docker容器中。一般来说，如果你有多个容器都在跑sshd，就得让SSH随机生成端口号以防止端口冲突。用SSH登陆着实需要几个步骤，在多个SSH一起跑的时候，就显得有些繁琐了。
###Problem ###问题
Basically the routine is to run docker ps:
用SSH登陆的基本思路就是使用docker ps:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e53a722096f0 aafd21071b99 /opt/bin/run_all 41 minutes ago Up 28 minutes 127.0.0.1:49251->22/tcp, 127.0.0.1:49252->9200/tcp es-b
0208431f9c7b aafd21071b99 /opt/bin/run_all 41 minutes ago Up 28 minutes 127.0.0.1:49249->22/tcp, 127.0.0.1:49250->9200/tcp es-a
If you scroll to the right of that you’ll see the randomly generated port in the PORTS column: 以上即是docker ps的输出结果，在最右面的PORTS这一列，可以看到随机生成的端口号：
127.0.0.1:49251->22/tcp
The next step is to type out the SSH command. You can either give in to RSI by copying the port with the mouse, or type it out: 接下来就是输入SSH命令，可以用鼠标复制端口号，或者直接输入端口号：
ssh root@localhost -p 49251
I think that’s too much work to simply SSH into a container! 仅仅是通过SSH登录容器而已，这也太麻烦了！
###Solution
I gave into annoyance and wrote a straightforward Python script to automatically do this for me. The Python script is calleddssh. It runs docker inspect, grabs the port, then runs SSH for you:
我怒了！于是我写了个Python脚本来解决问题。Python脚本叫做dssh，脚本里面先执行docker inspect，然后从结果中取出端口，然后再调用SSH登录容器：
#!/usr/bin/env python
import sys
import subprocess
import json
cmd = 'sudo docker inspect {}'.format(sys.argv[1])
output = subprocess.check_output(cmd, shell=True).decode('utf-8')
data = json.loads(output)
port = data[0]['NetworkSettings']['Ports']['22/tcp'][0]['HostPort']
cmd = 'ssh root@localhost -p {}'.format(port)
subprocess.call(cmd, shell=True)
You might notice it makes some assumptions which will crash the script if they’re not followed. There needs to be an argument for the container ID or name. In the example above I could use either "e53a722096f0" or "es-b" as the argument. There also has to be an sshd process port listening on 22, and a configured container to forward that port. 也许你注意到了，这个脚本中我们假设的一些条件如果不满足，脚本就会崩溃。我们需要一个参数来表示容器的ID或者名称。咱上面的例子中我可以指定参数为"e53a722096f0"或者"es-b"。同时还必须有一个sshd进程监听22端口，还要配置一个容器来转发22端口。
The output of docker inspect is a handy JSON string coming straight from the Docker Remote API. This in turn gives us the port we need. We then simply run subprocess.call and suddenly you’re in the container.
docker inspect命令的结果是由Docker Remote API输出的简单易读的JSON字符串，结果中也返回来我们需要的端口号。有了端口号，我们只需要调用subprocess.call来执行SSH命令，然后瞬间登陆到容器。
###Closing ###结束语
I did attempt this not long ago but failed. The attempt was to use docker-py but unfortunately it seemed to need root, which I couldn’t work a way to avoid it. I needed to SSH into docker as my non-privileged user because of SSH keys, so instead I made it print out the SSH command for it to be executed, but it was a cumbersome solution.
不久之前，我试了这个方法，但是没成功。方法中使用了docker-py，必须用root权限才能执行，所以我只能用非root用户来登陆Docker容器。所以我在脚本中把SSH命令打印出来执行，但是这样做显得太笨拙了。
If you want the latest version, it’ll be updated in my dotfiles repository on github. 请去我Github上的dotfiles仓库查看最新的脚本。 分类：Hacking，标签：docker, python, ssh 2014年2月2日 Gerald Kaszuba.
This entry was posted in Hacking and tagged docker, python, ssh on January 2, 2014 by Gerald Kaszuba.