Every nova user has a role associated with him. This role can be assigned at the time of creation of the account using "nova-manage add user (name)" or by editing the profile later using the OpenStack Dashboard by the project manager. The role can be either global or project specific in scope. All access in OpenStack is governed by roles. Each role has a predefined set of operations permitted within the relevant scope(global or local)
OpenStack ManualsOpenStack Compute Starter Guide - cactus
