after you install openstack on Ubuntu 14.04 server, you can use following nova commands

root@ssd:~# nova --os-username=admin --os-tenant-name=admin --os-auth-url="http://10.0.1.100:5000/v2.0/" usage
OS Password:
Usage from 2014-07-23 to 2014-08-21:
+---------+--------------+-----------+---------------+
| Servers | RAM MB-Hours | CPU Hours | Disk GB-Hours |
+---------+--------------+-----------+---------------+
| 2       | 556.80       | 1.09      | 1.09          |
+---------+--------------+-----------+---------------+

root@ssd:~# nova --os-username=admin --os-tenant-name=admin --os-auth-url="http://10.0.1.100:5000/v2.0/" --version
2.17.0