My Hyper-V Host
is running Windows Server 2012 R2 Datacenter, and on here I have about 15 VMs.
I just purchased a Windows Server 2019 Datacenter license. I'm ready to start creating 2019 VMs but I am not ready to rebuild the host with Server 2019. Is that a requirement for activating VMs running Server 2019? I believe best practice is to install Server 2019 Datacenter on the host, activate it using the unique activation key; then, any VMs I create on that host are activated using AVMA (Automatic Virtual Machine Activation) https://docs.microsoft.com/en-us/windows-server/get-started-19/vm-activation-19
But in my scenario, the host is running Datacenter 2012 R2. My plan was to (one at a time) start creating VMs running 2019 to replace the older VMs running 2012. (For example, I have a file server VM running 2012. I am going to create a new VM running 2019, configure it the same was as my 2012 VM and then decommission (delete) the 2012 VM). The end result is that one at a time, the VMs get replaced with new VMs. But the host (at least for now) will continue running 2012.
Is there another way to activate the VMs when the host is not running the first 2019 Datacenter instance? Can I create my first 2019 server as a VM and use that VM as the 'server' from where all of the other VMs are activated using AVMA? Or does AVMA only work if it can authenticate (activate) against a host
that is ALREADY running (and activated) with 2019 datacenter? I am probably answering my own question here but surely there must be a way to install newer OS VMs on an older host OS.