How do I license VMs on non-Hyper-V hypervisors with OEM?

Windows Server licensing is based on the physical hardware hosting the workloads, not on the hypervisor or the individual virtual machines. This model applies consistently across all virtualization platforms, including VMware ESXi, KVM-based solutions such as HPE Morpheus VM Essentials, and any other non-Microsoft hypervisor. Microsoft defines licensing in terms of physical cores on the server, with a minimum requirement of 8 cores per processor and 16 cores per physical server. All physical cores must be licensed appropriately before Windows Server workloads can be legally run on that hardware.

OEM Windows Server licenses are tied to the original physical server on which they are first installed. They are not designed for reassignment to different physical hardware, and they do not provide portability in virtualized environments. However, OEM licensing does not alter the virtualization rights of the Windows Server edition itself. Instead, the edition determines the allowed level of virtualization, while OEM status determines ownership and transferability. In practice, OEM licensing is suitable for static, single-host deployments but is not intended for dynamic or clustered environments where workloads may move between hosts.

Windows Server Standard and Windows Server Datacenter define the core virtualization rights once a physical host is fully licensed. With Windows Server Standard, licensing all physical cores on a host grants the right to run up to two Windows Server virtual machines on that host. To run additional VMs, the same physical cores must be fully re-licensed again, effectively stacking additional Standard licenses. With Windows Server Datacenter, licensing all physical cores on the host grants the right to run an unlimited number of Windows Server virtual machines on that same host. These rights are independent of the hypervisor and apply equally in VMware and KVM environments.

Virtual machine activation in non-Hyper-V environments relies on traditional Microsoft activation methods. Automatic Virtual Machine Activation is a Hyper-V-specific capability and is not available in VMware or KVM platforms. As a result, Windows Server VMs should be activated using either Multiple Activation Keys or a Key Management Service. These activation methods are separate from licensing entitlement and are used solely to activate the operating system instances.

Virtual machine mobility through technologies such as vMotion or live migration does not change licensing requirements in real time. Microsoft does not assign licenses to individual VMs or track their movement between hosts. Instead, each physical host must be fully licensed for the maximum number of Windows Server virtual machines it is expected to run at any given time. When a VM is migrated, the responsibility is simply that the destination host must already be properly licensed to support the workload. There is no concept of per-migration licensing consumption or dynamic license reassignment triggered by VM movement.

License reassignment rules, such as the 90-day restriction in Volume Licensing, apply to moving licenses between physical servers and not to VM-level operations. OEM licenses are generally bound to the original hardware and are not intended for reassignment, except under limited hardware replacement scenarios defined by Microsoft. In virtualized environments, compliance is achieved by ensuring each physical host is correctly licensed according to its installed Windows Server edition and core count, rather than by tracking individual virtual machine placement or movement.

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hth

Marcin