Today’s (Cloud) Tip…
Previously, VNET VMs were assigned dynamic internal IP addresses, and the StayProvisioned option was the only reliable way to keep the same internal IP address, but there was a billing cost in compute hours. With the new VNET internal static IP feature and using a separate subnet for these VMs, restarting stopped de-allocated VMs can also keep the same internal IP address.
The recommended usage pattern is to use separate subnets for static IP address VMs and dynamic IP address VMs. The static IP address subnet(s) would be used for all static IP address VMs, and customer should specify a different static IP address for each VM. The dynamic IP address subnet(s) would be used for PaaS web/worker roles and IaaS VMs without static IP addresses.
We support setting a VNET internal static IP address to its own currently running IP address, which changes the dynamic IP address VM to a static IP address VM. The customer can repeatedly assign static IP addresses for all VMs in that subnet, changing the entire subnet to consist of all static IP address VMs.
Read more about this functionality at http://msdn.microsoft.com/en-us/library/windowsazure/dn630228.aspx.