[atomic-devel] docker storage setup

[Andy Grimm <agrimm gmail com>]

Hi, all.  I have been working on a script to allow for more flexible
automated setup of docker storage on atomic hosts, and I'd like to get
some feedback.  First, here is a bit of context:

* we envision at least two distinct storage setup situations.  In the
simple case, the OS and docker data will live in the same volume
group, on the same disks.  But users may want their root filesystem to
be on a completely separate disk from their docker storage  (for
reasons of persistence, performance, whatever), so we should support
that.

* in a cloud environment, we must be able to launch an instance with a
larger volume than the original image, and have a way to automatically
use the space, and possibly to divide it between the OS and docker.

* in both cloud and server environments, users may want to specify
extra disks and have them added into the storage pool.

With those things in mind, I wrote up this script on Friday:
https://gist.github.com/a13m/715bf631ba3732aee7ab

The idea is that this would be a systemd unit which runs before
docker. If in a cloud environment, it would need to run after
cloud-init, so users could use a cloud-init script to populate the
config file.

The script is really just a rough draft at this point, so any and all
comments (including different use cases not mentioned above) are
welcome.  Thanks.

--Andy