I'm migrating from VMware to Hyper-V and, once the move is complete, I'd like to implement hotpatching for my servers. Is hotpatching available for on-premises Hyper-V virtual machines, or does it require running the servers as Azure VMs?
2 Answers
You don’t necessarily need Azure VMs. Supported Windows Server versions can use hotpatching through Azure Arc-enabled servers, including eligible on-premises Hyper-V VMs. Check the exact Windows Server version, licensing model, Azure Arc requirements, and subscription costs before building your design around it.
For Windows Server 2025, hotpatching can be enabled on eligible on-premises systems through Azure Arc, but it requires a per-core subscription and the servers must be Arc-enabled. If you also run Linux, look into kernel livepatch options such as Kpatch or Canonical Livepatch. These approaches rely on vendor-provided fixes that reduce the need for monthly reboots.
That matches what I found too—the feature isn’t free, so I’ll need to account for the Microsoft subscription. While planning the Hyper-V cluster, I’m also being careful with CSV BitLocker: I’ll keep a domain controller outside the cluster and avoid placing all domain controllers on the same CSV. I’m also planning to use a witness outside the cluster where possible.