I'm curious if the FQDN is persistent on Virtual Machines in Azure and if anyone could post an example how this would look.
Ie myhost-abc.vm.windows.net
By persistent I mean it will always be the same, never to be changed.
When you create a Windows Azure Virtual Machine (or Windows Azure Cloud Service) you first select a name for your service and based on your service name a DNS name is assigned to you. So example you have choosen service name ( with both VM or CS) "myservice" your DNS name will be and will remain same forever as long as you delete this service:
http://myservice.cloudapp.net
Now when create a Virtual Machine in service (or deploy your cloud application to this cloud service) you will have a VIP (external facing) assigned to your service and depend on your service endpoint configuration your service will interact to externally. These IP address will stay same as long as you do not delete the virtual machine(s) or deployment.
Also you can use CNAME setting (or DNS record) to route www.myservice.com calls to myservice.cloudapp.net this way if you change myservice to myservice1 by any reason, after setting proper CNAME your www.myservice.com call still go to your Azure service (VM or CS).
http://www.myservice.com ==>> http://myservice.cloudapp.net or http://myservice1.cloudapp.net
As you can see it does not matter if you choose myservice or myservice1 as service name, by setting proper CNAME/DNS setting you can route your actual DNS to Azure Service.