Published September 24, 2014
For some reason CentOS does not keep their historical CentOS releases available online in OpenStack cloud image format. They only have the very latest CentOS OpenStack cloud image available (if you know this to be incorrect, please let me know). However, the current and historical CentOS repositories are available online, and you can create your own custom OpenStack cloud image from them.
Published April 7, 2014
• Updated May 13, 2017
At the time of writing, unlike Red Hat, Fedora, CentOS, and Canonical, Debian does not create and distribute OpenStack cloud images. It is up to you to create your own. Debian now does create and distribute OpenStack cloud images. They can be found here.
I have seen steps using packer templates or virt-builder to create Debian 7 OpenStack cloud images, but I have not seen a step-by-step manual process to understand how it all works.