Each registrar will provide an option to unlock and specify name server(NS) records. An NS record indicates which DNS server hosts information for a given domain.

To use Cloud DNS you will need to modify your NS records so they point to Rackspace. This is done by providing the following NS records to your registrar:

dns1.stabletransit.com
dns2.stabletransit.com

That will get everything routed to Rackspace. Now we just need to server the proper server using our Cloud DNS tool.