[Docker service wont start]

I also just got this Error because my System ran out of memory and from the logs i could tell that it killed the process with the highest memory consumption (dockerd).
What worked for me was just running

/etc/rc.d/rc.docker start

in the Terminal to start it up again. Will of course not work if the docker image is really corrupt, but might be worth a try in cases similar to mine.

[Use Insecure Registry]

What worked for me was editing the '/boot/config/docker.cfg' file with

$ nano /boot/config/docker.cfg

and appending:

DOCKER_OPTS="--insecure-registry YOUR_REGISTRY_IP:YOUR_REGISTRY_PORT"

Then you need to restart the docker service to apply the changes with:

$ /etc/rc.d/rc.docker restart

This is also persistent across reboots.