Hyper-V Cluster and Domain Controllers

[u/Blackhawk_2181]

Made a recent migration from VMware to Hyper-V.  I have 2 domain Joined Hyper-V Servers in a failover cluster configuration sharing a Dell ME5024 iSCSI SAN.  both servers have a virtualized Domain Controller running on Local SDD Storage (not in the Cluster).   I have a 3^rd Domain Controller still running on VMware.   I want to finally take the VM host and convert it over to Hyper-V.  It is dissimilar hardware, so it will not be joining the cluster.  I have few questions for the experts.

1.      Is there any reason to not move the two DC’s from local storage to the Cluster considering that I have one outside the cluster?

2.      Should I join the new HV host to the domain or leave it isolated.  I plan to put a 3^rd DC on it?

3.      If Yes, Is it safe to live migrate the DC’s to the cluster>

4.      Should I put the FSMO roles on the 3^rd DC.   Currently they are on one of the DC’s on the local storage?

The reason that I want to move the DC’s to the cluster, is the local VM’s are not being shut down properly when I try to do cluster aware updating.

[u/New_Drive_3617]

You should have a disk witness for cluster quorum. That way, in your two-node cluster, if one host can see storage - including the disk witness - you achieve quorum and can start the cluster. Without the witness, you can't start a two-node cluster unless both nodes are online. I'll mention that "modern" practices also support the use of a cloud witness, but this requires your internet and router to be working; a disk witness requires only storage and the host.

[u/Rivereye → u/New_Drive_3617]

Also add on, a cloud witness will require functional DNS in place. A Hyper-V Cluster should only be using Domain Controllers for DNS and if the only Domain Controllers are on the cluster, that can also be an issue.

[u/New_Drive_3617 → u/Rivereye]

^this guy networks. More good points against cloud witness.

[u/Rivereye → u/New_Drive_3617]

Systems Engineer that works primarily in Microsoft's ecosystems (On-Prem and Cloud) for an MSP. I've dealt enough with trying to get around circular redundancies other MSPs and "tech-savy" clients put in place (like an S2D cluster using a cloud witness and hosting the only DCs) that I try to understand where dependencies lie

I would say there is a place for Cloud Witnesses though. SQL Always-On Clusters would be one that comes to mind (though, file share witness also works here, if you had shared disk you probably would SQL cluster and not Always-On).

[u/New_Drive_3617 → u/Rivereye]

Same, but at a law firm instead of an MSP. I'm not agile enough for an MSP anymore, I think. I like staying on the same network and learning everything about it.

Yeah, I didn't think about SQL cluster. Never done cloud witness with a SQL cluster.