Hot add disk on openstack

I made a automation method which can a add disk dynamically in openstack.
It is referred from cjung’s snapshot method.
ref: http://www.jung-christian.de/2015/12/create-snapshots-for-a-service-in-openstack/

and below is my code:
https://github.com/hatsari/manageiq-automation

I’m ruby & manageiq newbie so the code would be rough,
so if you have any advice, please tell me.

Also thanks to cjung.