title: Is there a UUID type of value in Linux that can uniquely identify an instance of a VM?
body: <p>I have an app that runs in Linux. Each one will try to get a UUID from OS and report to a centralized server. I want to make sure  all instance are running with globally unique UUID.</p>
  
  <p>If the linux is on bare metal, it can just read the UUID (say, from dmidecode command).  But if it's on VM, the UUID (from dmidecode) can potentially be equal since the VM can be copied or moved.</p>
  
  <p>Any ideas?</p>
  
  <p>By the way, for Linux running on physical hardware (not on VM), if user changes memory, NIC etc, will UUID change?</p>
  
  <p>Thanks in advance.</p>