title: Azure changing hardware
body: <p>I have a product which uses CPU ID, network MAC, and disk volume serial numbers for validation.  Basically when my product is first installed these values are recorded and then when the app is loaded up, these current values are compared against the old ones.</p>
  
  <p>Something very mysterious happened recently.  Inside of an Azure VM that had not been restarted in weeks, my app failed to load because some of these values were different.  Unfortunately the person who caught the error deleted the VM before it was brought to my attention.</p>
  
  <p>My question is, when an Azure VM is running, what hardware resources may change?  Is that even possible?</p>
  
  <p>Thanks!</p>