Comment 11 for bug 1413341

I reproduced the issue:
root@node-32:~# keystone --debug --os-token xJrbBgdH --os-endpoint http://192.168.0.87:35357/v2.0/ user-list
WARNING: Bypassing authentication using a token & endpoint (authentication credentials are being ignored).
DEBUG:keystoneclient.session:REQ: curl -i -X GET http://192.168.0.87:35357/v2.0/users -H "User-Agent: python-keystoneclient" -H "X-Auth-Token: TOKEN_REDACTED"
INFO:urllib3.connectionpool:Starting new HTTP connection (1): 192.168.0.87
DEBUG:urllib3.connectionpool:Setting read timeout to 600.0
Unable to establish connection to http://192.168.0.87:35357/v2.0/users

As workaround we can just restart keystone service and after that it responds.