centos - Docker fails to start due to "volume store metadata database: timeout"

Question

I have followed the installation instructions of Docker CE for CentOS. Initially this worked. At some point the system was restarted and now starting Docker fails. Appreciate expert eyes on this matter...

systemctl start docker produces:

Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.

systemctl status docker.service produces:

Apr 21 11:25:23 sec-services-build-1 systemd[1]: Starting Docker Application Container Engine...
Apr 21 11:25:23 sec-services-build-1 dockerd[9693]: time="2017-04-21T11:25:23.370390797+03:00" level=info msg="libcontainerd: previous instance of containerd still alive (8908)"
Apr 21 11:25:23 sec-services-build-1 dockerd[9693]: time="2017-04-21T11:25:23.382492171+03:00" level=warning msg="overlay: the backing xfs filesystem is formatted without d_type support, which leads to incorrect behavior. Reformat the filesystem with ftype=1 to enable d_type support. Running without d_type support will no longer be supported in Docker 17.12."
Apr 21 11:25:23 sec-services-build-1 dockerd[9693]: time="2017-04-21T11:25:23.382547668+03:00" level=info msg="[graphdriver] using prior storage driver: overlay"
Apr 21 11:25:24 sec-services-build-1 dockerd[9693]: Error starting daemon: error while opening volume store metadata database: timeout
Apr 21 11:25:24 sec-services-build-1 systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
Apr 21 11:25:24 sec-services-build-1 systemd[1]: Failed to start Docker Application Container Engine.
Apr 21 11:25:24 sec-services-build-1 systemd[1]: Unit docker.service entered failed state.
Apr 21 11:25:24 sec-services-build-1 systemd[1]: docker.service failed.

Answer 1

From here: https://github.com/moby/moby/issues/22507

I ran:

ps axf | grep docker | grep -v grep | awk '{print "kill -9 " $1}' | sudo sh 

I was then able to restart docker using:

sudo systemctl start docker