Two things on this: in other barclamps, we actually change the environment to set the right environment variable instead of passing --os_username and other arguments. I don't have a strong opinion on this, but making things consistent would be nice.

The other bit: we now have SSL support for keystone and nova, and this command might require using --insecure. You would need something like https://github.com/crowbar/barclamp-quantum/commit/3a5e807fb002acf413e97059cb46891bc5491388 to determine if --insecure is needed.