Comment 1 for bug 1771709

If I understand this correctly, the Keystone charm uses 'service_hostname': resolve_address(ADMIN) to set the relation data, which reflects right through to the neutron-gateway charm via the neutron-api charm and the identity relation there.

If we were to add an option to the keystone charm to supply the internal as well as admin hostname, we could then use the 'use-internal-endpoints' to collect the internal auth url address.