Well, that seems alright. However, Glance log definitely seems to point out to connection failures regarding Keystone. So I would guess that there is some intermittent network failure. I know this doesn't help you much but such a case is not easily reproducible, and rightly so because that would mean Keystone wasn't working correctly. So I would suggest changing your installation environment, maybe a different server or network. I'm hoping that you won't have the same problem.
Well, that seems alright. However, Glance log definitely seems to point out to connection failures regarding Keystone. So I would guess that there is some intermittent network failure. I know this doesn't help you much but such a case is not easily reproducible, and rightly so because that would mean Keystone wasn't working correctly. So I would suggest changing your installation environment, maybe a different server or network. I'm hoping that you won't have the same problem.