Testing Windows Server 2016 With Nested Hyper-V

There are a lot of features you expect today from a hypervisor; and I'm glad to see that the Hyper-V role coming in Windows Server 2016 will support nested virtualization. This is a feature that's been around on other Type 1 hypervisors for a while, and for Hyper-V this is a bit overdue; still, happy and ready for it.

On a Role
In Hyper-V, nested virtualization basically means that a Hyper-V host can run a virtual machine (VM)  capable of running the Hyper-V role as well. In the simplest of configurations, one Hyper-V (running Windows Server 2016 or Hyper-V Server 2016) host could have one VM that runs Hyper-V Server 2016 and another virtual machine.

Nested virtualization has been a boon for home lab and workgroup lab practice for years, and one of the most requested features for the lab use case. Personally, I'm ready for this and the timing couldn't be better.

Performance Hits
The first thing to note with nested virtualization, regardless of hypervisor platform used, is that it suffers in terms of performance with the bare-metal equivalent. In fact, it's a level of overhead that would in most situations render it "unsupported" for production. This is why it's primarily a lab use case; keep this in mind when it comes to production workloads. It'll be interesting to see Microsoft's official support statement on nested virtualization for use in datacenters and in Azure.

Now that nested virtualization with Hyper-V is an option (after downloading the technical preview of Windows Server 2016), what are the best use cases?

Use Cases
The primary ones for me are to work with the new storage features that apply to Hyper-V. Personally, I don't think the world was ready for the capabilities that SMB 3.0 brought to the table with Windows Server 2012. The first release was a network storage protocol that's agnostic and easy to support, yet ready for a sizeable workload with Hyper-V VMs. Many shops are entrenched in the world of SANs and storage practices of decades past; nested virtualization would be a good place to become confident with SMB 3.0 -- or dismiss it -- based on your experiences.

Another use case is centralized management with System Center Virtual Machine Manager (SCVMM). You need a larger infrastructure for SCVMM make sense; two-host clusters need not apply. If SCVMM is in your future, some lab time enabled by a nested virtual machine manager can give you a look at the intricacies of managing Hyper-V at scale, and using the broader features like migration of VMs.

Nested virtualization for Hyper-V is a big step, and a gateway to lab tasks that provide a closer look at advanced features. I'll be using it to check out the newest Windows Server 2016 features.

Posted by Rick Vanover on 07/30/2015 at 11:19 AM