The OpenStack extension mechanism makes it possible to add functionality to OpenStack APIs in a manner that ensures compatibility with existing clients. This capability allows OpenStack operators and vendors to provide innovative functionality to their clients and provides a means by which new features may be considered in upcoming versions of OpenStack APIs.
This document describes the extension mechanism in detail. It provides guidance to API implementors and clients on developing and consuming API extensions, it describes the rules by which extensions are governed, and it describes the process used to promote API extensions to new features.