Sahara deploys a cluster of machines based on images stored in Glance. Each plugin has its own requirements on image contents, see specific plugin documentation for details. A general requirement for an image is to have the cloud-init package installed.
Sahara requires the image to be registered in the Sahara Image Registry in order to work with it. A registered image must have two properties set:
The username depends on the image that is used and tags depend on the plugin used. You can find both in the respective plugin’s documentation.