Today I got a docker daemon not responding to commands (docker ps, docker run...)
Even after restarting service
In /var/log/docker I got this:
time="2017-03-01T08:28:58.43946917Z" level=fatal msg="open /var/run/docker/libcontainerd/containerd/81623262351dfc42c5e87aa8df11592a57f2d14a468476620c7c4d6c89de1958/state.json: no such file or directory"

The solution was to stop docker service, remove this /var/run/docker directory and restart docker service