/var/lib/docker

Question: Does '/var/lib/docker' holds files with owner different from root, some special rights?

Point is: "cp -r" is not safe. It doesn't preservers original owner/rights.

Add this to /etc/fstab.
Mounting from here will confuse a user.
User running VM without knowledge of cloud-init will be very confused.

Still more then 80 characters.
Point is: if you split a string do it in a right way with purpose in mind.

Maybe add a docstring with description of "disk_size". Is it bytes? kilo/mega/etc ?....

I would like to follow http://sphinxcontrib-napoleon.readthedocs.io/en/latest/example_numpy.html

docstring standard.

no-no-no

1. please keep one command for spawning a qemu process , with a command line argument.
2. Create a command line appropriately.

No reason for this line.
os.environ.get returns None for unknown env variable

Please constrict try/except block to code that throws exceptions.

Kill the qemu process -- this code is already in master.

• This PR cannot be clearly merged with master. Please send PR against current master.

Touching/moving /var/lib/docker is bad idea.
It is mach better to extend docker storage in a standard way:

http://www.projectatomic.io/docs/docker-storage-recommendation/

Possible solution:

1. Add device to etc/sysconfig/docker-storage-setup
2. Invoke docker-storage-setup