Update on Nano Server and Semi-Annual Release

Posted on June 29, 2017 by Aidan Finn in Windows Server with

Microsoft recently made some announcements about the end of infrastructure roles for Nano Server and the twice-yearly updates to Windows Server. Microsoft has since clarified some of the points, so I thought it would be worth revisiting these inter-related topics.



The Announcements

Microsoft made two announcements:

  • Semi-Annual Releases: Microsoft will be starting a new program that Software Assurance (SA) customers can opt into. With this program, you will get a new release of Windows Server every Autumn/Fall or Spring. Non-SA customers will continue to get the every-3-years or so releases that will contain most Windows Server features.
  • Nano Server: It was announced that all of the infrastructure roles of Nano Server, such as Hyper-V and Storage Spaces Direct, and the ability to use Nano Server in a virtual machine, would be removed in the next release of Windows Server. This will probably be in September.

Many of the questions were raised after these inter-related announcements. Nano Server was supposed to be supported only in SA. To be supported, you had to run it in the Current Branch for Business, which was supposed to result in twice-yearly releases.

Jeff Woolsey, a Principal Program Manager in Windows Server, is a guy we Hyper-V veterans respect for his frankness. We also enjoyed his back-and-forth via blog posts with VMware back in the 2008/R2 era. He recently responded to a number of questions on the semi-annual release blog post and filled in some of the knowledge gaps.


Nano Server

A small but vocal niche was quite upset about the reduced role of Nano Server. The reality is that the adoption of and feature requests for Nano Server drove the change. Jeff said:

“The adoption for Nano Server as an infrastructure has been a mere fraction overall and the requests are substantially different. Users deploying Nano Server on hardware as an infrastructure role want us to add things like a Setup experience, 32-bit support, more drivers, Roles and Features, and more. At this point, Nano Server looks like Server Core or Microsoft Hyper-V Server 2016.”

As I expected, very few people deployed Nano Server in production. Of those people, they wanted so many changes that Microsoft was essentially going to be making a new version of Server Core. Why do that?

The future of Nano Server is in Windows Server Containers. This means that Microsoft will be removing the Nano Server “image” from the Windows Server media. Container images are downloaded from the Internet to a local image repository.

This decision allows Microsoft to remove more from Nano Server, which makes it smaller again. It becomes even better suited for containerized workloads. An interesting note on this subject was:

“WMI is also removed from the Nano Server base. Therefore, any PowerShell cmdlets based on WMI will not work on a Nano Server container.”

Remote management must be modernized for containerized applications.

What about support for existing Nano deployments? While Windows Server has the classic 5 years mainstream support plus 5 years of extended support with optional paid for Premium Support, Nano Server is different. Nano Server requires you to be in the Current Branch for Business, which is being renamed in the Server world to Semi-Annual Channel. Jeff clarified the support for existing Nano Server deployments. You do not have much time left to migrate from Nano Server!

“The version of Nano Server that we shipped in October 2016 will be supported until spring of 2018. We encourage you to migrate to the Server Core option of Windows Server 2016 that is available now or else the new Server Core option feature release that is coming this fall.”

Semi-Annual Releases

The first thing we need to know is that not all installation options of Windows Server are being included in the Semi-Annual Channel:

Support for Semi-Annual Channel and Long-term Servicing Channel with WS2016 [Image Credit: Microsoft]

Support for Semi-Annual Channel and Long-term Servicing Channel with WS2016 [Image Credit: Microsoft]

The assault on the 70 percent or more of companies that work with a GUI installation of Windows Server continues. Clearly, I have run a few surveys of the years. If you have SA on your Windows Server and Windows Server CALs (both are required) and you want to opt into the Semi-Annual Channel, then you must be running Server Core.

I never run Server Core in production for the same reasons that I would never run Nano Server in production. I guess that I am not going to be getting these updates until the next Long-term Servicing Channel release.

I will not be alone. As I said, I have run a few surveys of the years. The shift from Full installations to Server Core since 2008 R2 has been just 10 percent (from 20 percent to 30 percent). Note that the Core numbers were skewed by those using the free Hyper-V Server, which is based on Server Core.


Those running Windows Server in Azure will inherit the Semi-annual Channel option because they are paying for Windows Server (via the virtual machine) via either SA (Hybrid Use Benefit) or per-minute via the cost of the machine. Windows Server CALs are not required for Azure virtual machines because they are licensed per core.



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