How to fix Docker

Sometime the Docker won't stop and it just hangs on any commends.

So far I haven't figured out a way to fix it without rebooting the machine.

Even worse: docker daemon won't start after reboot. I need to reinstall docker to get it to work. And I had to use the following commands to uninstall and reinstall to make it work.

$ sudo apt-get autoremove --purge docker-engine
$ rm -rf /var/lib/docker
$ sudo apt-get install docker-engine