I have just released WolkenBrot v0.3 with OpenStack support. WolkenBrot is my own little program to bake cloud images. Then name means "Cloud Bread" in German. It's not equal in features to Hashicorp's Packer, but it's MUCH simpler to use and hack on.
I recently started working with AWS again, after 5 years hiatus, and I still have clients using OpenStack. Hence, I thought it would be useful to un-dust WolkenBrot and give it OpenStack support.
I've not used for 5 years, and it took me a few hours to add OpenStack support to it. Mostly, because the Python Client for OpenStack is extremely easy to use. Check out the examples on how to use it it. Give it a spin and send some feedback!