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Microsoft goes cloud KERR-AZY, chops Windows Server to bits

Hacked-down Nano Server goes great with Hyper-V containers, says Redmond

Updated Microsoft has taken wraps off its latest tools for the modern data center, including a new application container tech for Windows and a micro-sized version of Windows Server that's tailored for cloud deployments.

We first heard rumors of Microsoft's so-called Nano Server in March, when a leaked slide deck suggested that Redmond was working on a version of its server OS that included only the core components and none of the fluff.

Microsoft confirmed those plans on Wednesday, describing Nano Server as "a purpose-built operating system designed to run born-in-the-cloud applications and containers."

This bare-bones OS includes nothing save what is required to get a system up and running. Much like Windows Server's Server Core installation option, it's designed to run headless, so it includes no GUI stack, local logon, or Remote Desktop support. All management is handled via Windows Management Instrumentation (WMI), PowerShell, and Visual Studio integration, including remote debugging support.

Nano Server isn't just a renamed Server Core, though. It's actually even smaller than that, and is missing several components that are available in Server Core by default. What components it does have, though, will be API-compatible with its grown-up Windows Server cousin. Think of it instead as Microsoft's answer to tiny, cloud-centric Linux distros like CoreOS, Red Hat Atomic Host, and Snappy Ubuntu Core.

Such "micro-OS" designs offer several advantages. Microsoft says the disk image footprint for Nano Server is 93 per cent smaller than for Windows Server. Because it omits so many Windows Server components, it's subject to 92 per cent fewer critical security bulletins out of the box. And admins find they have to reboot the system 80 per cent less often.

"It is designed for fewer patch and update events, faster restarts, better resource utilization and tighter security," the Nano Server team explained in a blog post.

Redmond says it is also working with tool vendors – Chef was named – to make sure Nano Server integrates well in DevOps environments and with continuous deployment workflows.

Going Hyper over containers

But another role for Nano Server, Microsoft said, will be as a host for applications and micro-services running in Windows Containers.

Redmond first started talking up containerization – which has become the tech du jour in the Linux world – in October 2014, when it announced it had partnered with Linux container maven Docker to bring similar capabilities to the next version of Windows Server.

On Wednesday it expanded upon those plans with a new kind of Windows containers called Hyper-V containers. Unlike standard Windows Server Containers, Hyper-V containers run on Microsoft's virtualization hypervisor, ensuring that code running in one container is completely isolated and has no chance of affecting other containers or the host OS.

That design will likely incur a slight performance hit, but it also makes Hyper-V Containers useful for multi-tenant environments or where running untrusted code is a requirement. Server Containers, on the other hand, need no hypervisor, so they spin up faster and they can use memory more efficiently, allowing for greater container density.

Microsoft's architecture for Windows containers, including Hyper-V Containers

Microsoft is going wide with containers, adding Hyper-V containers to its original architecture diagram

Which style of container you use is entirely up to you. Both kinds will be manageable via the same Docker-compatible tools.

"A developer can create a container image using a Windows Server Container and deploy it as a Hyper-V Container or vice-verse without any changes other than specifying the appropriate runtime flag," a Microsoft spokesperson explained to The Reg via email.

As for when we'll be able to get our hands on this stuff, that's not clear. Redmond has said that the next version of Windows Server won't reach general availability until 2016, but it's possible we could get our first look hands-on look at Windows Server Containers as early as May, when the next Technical Preview of the server OS is expected to arrive.

Unfortunately, there was no word on when previews of Nano Server or Hyper-V Containers might be available. But you can bet that Microsoft will have lots more to share about both at its annual Build conference, due to take place in San Francisco from April 29 through May 1. ®


Microsoft got in touch to say that Nano Server will be available in preview when the next Windows Server Technical Preview arrives in May. For Hyper-V Containers, on the other hand, we'll have to wait until later in the year.

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