Every service that receives requests with a token needs to communicate with keystone to verify a user's identity. A rough diagram of how keystone works can be found in the sequence diagram:http://docs.openstack.org/trunk/openstack-identity/admin/content/what-is.html While there is a mass of users or the scale of cloud becomes huge,will keystone be the bottlenect? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openstack.org/pipermail/openstack/attachments/20120508/b954a2ed/attachment.html>