In OpenStack, every service defines the access policies for its resources in a policy file, where a resource can be like an API access, it can create and attach Cinder volume, or it can create an instance. The policy rules are defined in JSON format in a file called policy.json.
Only administrators can modify the service-based policy.json file, to control the access to the various resources. However, one has to also ensure that any changes to the access control policies do not unintentionally breach or create an option to breach the security of any resource. Any changes made to policy.json are applied immediately and it does not need any service restart.
After a user is authenticated, a token is generated for authorization ...
