Sorry for being such a noob, but how do I determine what I should use as my auth url. I ask because when I execute ...

$ nova list

... I get this error message ...

ERROR (CommandError): You must provide an auth url via either --os-auth-url or env[OS_AUTH_URL] or specify an auth_system which defines a default url with --os-auth-system or env[OS_AUTH_SYSTEM]

I am using devstack as I am a total noob.

Thanks