Comment 2 for bug 1625338

I hit this exact failure. Restarting all apache2 services on all keystone units fixed it. The weird thing is, keystone/2 was constantly erroring like this:

(keystone.common.wsgi): 2016-12-16 21:58:55,700 WARNING Authorization failed. The request you have made requires authentication. from 10.5.1.76
(keystone.common.controller): 2016-12-16 21:59:08,183 WARNING RBAC: Bypassing authorization
(keystone.common.wsgi): 2016-12-16 21:59:08,188 WARNING Could not find token: e1ab5fc118354edbad22a541a1ad4ff4
(keystone.common.wsgi): 2016-12-16 21:59:25,725 WARNING Authorization failed. The request you have made requires authentication. from 10.5.1.76
(keystone.common.wsgi): 2016-12-16 21:59:55,742 WARNING Authorization failed. The request you have made requires authentication. from 10.5.1.76
(keystone.common.controller): 2016-12-16 22:00:03,301 WARNING RBAC: Bypassing authorization

*BUT*

10.5.1.76 is actually keystone/0. That IP address was the only error in the logs. I'll attach logs from the keystone units.