It turns out there also is work happening that will trim down Windows Server 2016, or at least one version of it. On Twitter, Microsoft Distinguished Engineer and father of PowerShell Jeffrey Snover was encouraging server owners to "only install what they need," in terms of features. In hindsight, it looks like Snover's comments may have been hints about the coming Nano Server.
The Nano Server won't need to be constantly administered; remote management and automation will be provided by Core PowerShell and WMI, according to the slides. Core PowerShell is PowerShell refactored to run on the CoreCLR.
Nano Server will be available as a host OS for physical hardware, a guest OS in a virtual machine and/or as a container OS, the slides say. The coming Windows software development kit and Visual Studio 2015 will both target Nano Server.There will be a limited test program for Nano Server in "early 2015," but it won't be part of the next Windows Server preview, which is due some time in the next few months. (It will be in the next release after that, the slides say.)
Not everything will run on Nano Server, such as Fax Server and Remote Desktop Services, but Nano Server will be the "new foundation for all components."
Recently, I had noticed mention of the Guardian Server role in a description of one of the upcoming Microsoft Ignite conference sessions:
Harden the Fabric: Protecting Tenant Secrets in Hyper-V
In today's environments, hosters need to provide security assurance to their tenants. "Harden the fabric" is a Windows Server and Microsoft System Center vNext scenario, which includes enhancements in Hyper-V, Virtual Machine Manager, and a new Guardian Server role that enables shielded VMs. Technologies which ensure that host resources do not have access to the Virtual Machine or data.
One of my contacts said this new Guardian Server role is an implementation of the Host Guardian Service, which ensures that a protected VM only runs on trusted hosts. In other words, the service will verify that the host is truly trusted.