From Fedora Project Wiki
The heat project (https://github.com/heat-api/heat) comes with a tool like this (uses oz to install a jeos + cloud-init and also registers the image with glance.
" Please provide the distro, arch, and instance type.
Usage: heat jeos-create <distro> <arch> <instancetype> instance type can be: gold builds a base image where userdata is used to initialize the instance cfntools builds a base image where AWS CloudFormation tools are present
"
Implementation here (we are separating out the AWS tools + jeos creation): https://github.com/heat-api/heat-jeos/blob/master/heat/utils.py
-Angus Salkeld