you don't want to use the Clud Service host name to communicate between the VMs.
If you want to use DNS, you have to provide DNS - you don't need that too.
For that particular scenario, I would recommend something even simpler:
- Put the VMs in the same Cloud service
- Do not go for any Virtual Network or DNS Solutions
- Use VM Name to connect between the machines.
when the VMs are deployed in the same Cloud Service and not in Virtual Network, Windows Azure provides automatic name discovery. The simplest approach is usually the best.
For more information on name resolution scenarios in Windows Azure, read this paper.