Docker and Google Compute Engine

Participated in a hackathon (hackforchange.org) this past weekend and there were some Google credits available so I figured I'd see how easy it was to get Docker running on Compute Engine. Turns out, very easy thanks to this post from Google: Containers on Google Cloud Platform.
The only real gotcha that I ran into was that I ran out of disk space almost immediately after installing Docker registry. What?! Yup, since Compute Engine starts you out with an 8GB disk you need to:

1. Provision a bigger disk and attach it
2. Move Docker onto the bigger disk

Attaching more disk is thoroughly documented by Google (see: Disks) but it took quite a bit of searching to figure out how to move Docker so I figured I'd post with what I did.

We're going to assume I added a bigger disk and mounted it to /docker-storage.

1. Stop docker - 'service docker stop'
2. Edit /etc/default/docker - you're looking for the line that sets DOCKER_OPTS.  You want to add a -g flag and where you want Docker to run from.  In my example, I prepended

   -g=/docker-storage/docker

3. Move the files from the default Docker location (/var/lib/docker) to the new mount:  'cd /var/lib; mv docker /docker-storage/'
4. Restart docker - 'service docker start'

That should be all it takes.