If you create a Role (Web, Worker of VM) on Windows Azure, the machine always gets a generated Computer name. This name always starts with RD followed by a number. RD stands for Red Dog, which was the codename of Windows Azure.
But the computer name can be customized. In the Service Configuration cscfg file you can enter a vmName besides a Role name. The vmName will be the Computername of the machine on Windows Azure and it will be suffixed with a number too.
See below. I have an app with 2 roles, one WebRole and one WorkerRole. The WebRole I want to call MMWEB and the WorkerRole I want to call MMWORK.
When you RDP to the Role instance you see the name in the Computer properties.