r/HyperV

Having trouble re-joining a host back to a cluster, hoping someone can give me some insight because I cannot find many similar issues:

One node (call it Node A) cannot rejoin the cluster after being drained/rebooted for routine maintenance. The other two nodes are completely healthy, holding quorum, roles all online. Node A's Cluster Service runs locally but every join/form attempt ends the same way:

Get-ClusterNode shows Node A stuck in Down state (occasionally rolls back to no record at all)

Cluster log: repeated [QUORUM] Fail to form/join a cluster in 6-7 minutes → FatalError: join/form timeout (status = 258) (WAIT_TIMEOUT)

Live event log: Event 1650 (lost/established UDP connection on the management endpoint) and Event 5417 ("Cluster Service has terminated due to a fatal error... Error Code: 3473458" = ERROR_CLUSTER_JOIN_ABORTED), repeating in a loop

The NetFT pseudo-adapter (Microsoft Failover Cluster Virtual Adapter, shows as Local Area Connection* N in Get-NetAdapter -IncludeHidden) cycles Disconnected → Up → Disconnected on an irregular ~10-150 second cadence, indefinitely

Meanwhile vEthernet (Management) underneath it stays Up continuously the entire time — confirmed via a parallel live polling loop. NIC RX/TX counters on the same adapter climb steadily throughout, never stalling

Hyper-V Manager \"New VM\" Wizzard on 29639.1000 with the flag enabled

Hey it seems MS took at least one suggestion out of https://www.reddit.com/r/HyperV/comments/1o9siyz/comment/nk83qgb/ . It's the smallest QoL fix ever but who would have expected we would get an update 😄

Found this on Windows Insider builds (29639.1000), you can enable it with the following but it'll likely come in the next release or something:

.\ViVeTool.exe /enable /id:55721547

Greetings!

I'm replacing a standalone workgroup 2016 Hyper-V server with a new 2025 host. I was hoping to utilize shared-nothing Live Migration for a zero-downtime move of the VMs, but turns out they need to be joined to an active directory domain, according to the error I received when trying to enable it in Hyper-V Manager.

That said, is there any way around this without joining the hosts to Active Directory, or possibly a third-party solution that can facilitate a live migration?

I've played with Starwind Converter, and though it works well, it still required the source VM to be shut down and destination VM to be powered on. Not a live no-downtime method.

I'm beginning with virtualization. I have a PC with Windows 10 Pro that can't be upgraded to Windows 11. I installed Hyper-V on it and created two VMs: one with Windows 10 Pro to install and practice automation software like PLCs, SCADA, and DCS; and the other with Windows Server 2025 to install a free and open-source CRM (Dolibarr) and possibly Odoo. I also want a third VM with Windows Server 2025 to create and manage databases, which would only have local network access for other users.

In Hyper-V, I created three switches: internal, external, and private.

For the Windows 10 Pro VM, I only want it to connect to the host PC, so I configured it as an internal network. For the Windows Server 2025 VM, I configured it as an external network so it can have a web server and everything necessary for CRM users to access it on the local network and/or from the internet.

The issue is that none of the three switches, nor the Hyper-V DefaultSwitch itself, have internet access. It was necessary to create a bridge on the host PC between the host's network card and the virtual network card of each VM.

I can access the internet from the host PC through my internet service provider's router, which have a Class C local network.

I appreciate everyone's valuable assistance in providing clear guidance on how to configure both the host PC and Hyper-V, as well as each VM with the required components.

My background is not in IT, but in electrical engineering, so I'm just starting out with network and server installation and configuration. I'm doing this out of necessity for the startup my wife and I started.

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.

Two HP DL560 Gen10 hosts running Hyper-V, Citrix VDI on top. We bought a T4 per host to test GPU acceleration and the idea was to split each card over multiple VMs, 4 or 8 or whatever it can handle. Later (in two to three years) we'll upgrade our environment to new servers.

Then I went to install it and got stuck (bad investigation? who can say but fugg me). The vGPU package has no host driver for Windows Server at all, the Host_Drivers folder is ESXi and KVM stuff only? So am I supposed to run the guest driver installer on the Hyper-V host itself, or is there a separate download I'm not finding? And where do you even get the right files, is that the licensing portal only? It seems that licensing portal is not complete for Hyper-V.

From what I can find in the docs Hyper-V never supported normal vGPU, and GPU-P on Server 2025 doesn't list the T4 as supported. Which would mean DDA, whole card to one VM, is the only thing we get. Fine if that's true, I just want to be sure before I go back to my boss with it.

If DDA is the answer, is dropping the T4 into one multi session VDA and letting everyone share it inside that VM a reasonable setup, or does that fall over in practice?

Hyper-V is staying, so no ESXi suggestions please.

I recently installed Pihole on an Alpine Linux VM via HyperV and am routing my network traffic through it with my router. This is all working great EXCEPT my desktop with the host OS can't access the web interface for Pihole and doesn't seem to be routing its traffic through Pihole either. Every single other device on my network is working as expected (CAN access the web interface and is being recognized as a client).

Attached is the virtual switch the VM is operating with

Any ideas?

https://preview.redd.it/ldg0vyppzqih1.png?width=449&format=png&auto=webp&s=e8b05abf9b87924dd9f14fb3fefc2d4154b68b76

Всем привет. Терминальный сервер на виртуалке Hyper-V (Windows Server 2025), внутри Хоста на Windows Server 2025 спустя день работы начинает дико тормозить.

Дескрипторы постоянно растут. Показатели железа в норме. Грешил на сеть, потом на настройку ВМ.

Сейчас уже и не знаю что думать. Спасает только перезагрузка.

Когда перезагружаю - первое время сервер летает. Потом возвращается к тому же состоянию.

Куда смотреть, что искать, что настроено некорректно? Почему это не работает И как это должно работать правильно? Помогите разобраться, знатоки!!!

Looking for feedback from organizations running a 4-node Hyper-V S2D cluster (Rack Awareness enabled)

Hi everyone,

I'm interested in hearing from people who are running production Hyper-V clusters with Storage Spaces Direct (S2D) and Rack Fault Domain Awareness.

Our environment has the following architecture:

• Windows Server Failover Cluster
• 4 Hyper-V nodes
• Storage Spaces Direct (S2D)
• 2 physical racks
• 2 nodes per rack
• Rack Fault Domains configured correctly
• Storage pool configured with Rack Awareness
• 2-way mirror resiliency
• Cluster Shared Volumes (ReFS)
• Around 100+ production virtual machines
• Automatic Storage Rebalancing disabled (manual balancing only)

Networking

Each host has four physical NICs:

• NIC 1 + NIC 2: Dedicated for the Hyper-V virtual switch (SET Team) carrying VM traffic.
• NIC 3: Dedicated to storage, cluster communication and live migration.
• NIC 4: Dedicated to storage, cluster communication and live migration.

The storage/cluster network uses SMB Multichannel across the two dedicated adapters. RDMA is not enabled (standard Ethernet only).

Our primary goal was to tolerate the complete loss of one rack while keeping production online.

During a recent Disaster Recovery test, we intentionally shut down the two nodes from one rack. The remaining two nodes successfully kept all VMs online for approximately two hours before the cluster started experiencing CSV Auto Pause events, CSV draining, storage instability and eventually multiple VM outages.

At this point I'm more interested in understanding how common this architecture is in real-world production.

Some questions for people running S2D:

• Are you running a similar 4-node / 2-rack design?
• Is Rack Awareness enabled?
• Are you using RDMA, or are you successfully running without it?
• How are your storage and cluster networks configured?
• Have you ever tested losing an entire rack?
• Did the cluster remain stable indefinitely, or only for a limited time?
• Have you experienced CSV Auto Pause or storage instability after operating for an extended period on only half of the nodes?
• Would you recommend this architecture today, or would you instead deploy more nodes or another topology?

I'm especially interested in hearing from organizations that have performed real DR tests rather than theoretical discussions.

Any lessons learned, Microsoft recommendations, or production experience would be greatly appreciated.

Thanks!

I'm running Ubuntu 26. How do I get the IP address of the VM to show up under Networking->IP Addresses in the Hyper-V Manager?