Keystone V3. The openstack identity v3 api, provided by keystone, offers features that were lacking in the previous version.among these features, it introduces the concept of domains, allowing isolation of projects and users. The server with the openstack identity service turned to serve as the certification authority (ca) and tokens received digital signatures.
In the icehouse release the keystone v2 api was deprecated 2. 1 setting up devstack to run swift with keystone v3 api. We also have an older cluster (based off juno using keystone v2) where the auth succeeds.