[solved] Registering and unregistering when powering-on and -off

Hi,
I have a small concern about registering and unregistering systems. I'm using Red Hat Cloud Access - I'm running RHEL in Azure with my own subscriptions. My solution is using scaling on demand, generating new RHEL instances from custom image. Hostnames are dynamic. Am I allowed to register system when it is starting and unregistering when system is shutting down? Those VMs are not long-living VMs - solution itself, yes.