How to add a new node to an existing Hyper-V cluster?

Question

Virtualization

There are two servers in a cluster on Windows Server 2016 Datacenter. He is productive and cannot be stopped. Now you can add another server. All servers are identical in hardware. Windows Server 2019 Datacenter was installed on the new server (we plan to update the old nodes as well). Actually, the question is:
When checking for server compatibility, I read a notification that the storage connected to the servers will be unavailable during the check. Do you mean shared storage ClusterStorage? Virtual machines are also stored there. If it is not available, what will happen to the VMs? Will their network fall off? Will they be launched at all? I have no idea how to properly add an additional node without stopping.

Answer 1

Yes to all questions. Whatever happens to the servers, do it all in the "maintenance window". Stop the server. And do it.
As for the fact that different OSes are not sure, I think it would be better if they were the same everywhere. It is not in vain that it is written that the cluster nodes have the same set of updates. And your OS will be different.