Comment 11 for bug 1432242

Here is the RC of "unexpected token invalidation" as I see it. We use memcached backend for keystone to store tokens, and deployment process does restarts of memcached service. It is expected to restart it as we configure memcached as well. But all tokens are vanished then without a proper expiration procedure, so the keystonemiddleware.auth_token reports "Could not find token" for such tokens as keystone considers them alive.