"We do find it to be a watershed moment, especially considering the past, but it's not surprising," said Amanda McPherson, vice president of marketing and developer services at The Linux Foundation, in an email interview. "Cloud computing has mostly been a Linux and open-source affair. Microsoft is a smart company and will do what they need to do to be a player in cloud, and in this case it means doing something that was anathema in its past: agreeing that another operating system is needed in order to be technically relevant. I'm sure many Redmond inhabitants aren't too happy about this, but it's good for users."

Over the past year, Microsoft engineers on ensuring the driver for its Hyper-V Windows-based hypervisor works with Linux, the underlying hypervisor for Azure. , Microsoft has also worked quite a bit with Suse on adapting Linux to work on Hyper-V.

"Microsoft recognizes that their customers run more than just Windows in their enterprise, and this is an opportunity for Windows Azure to run as many workloads as possible," said Wade Wegner, chief technology officer for Aditi Technologies, a technology services company and Microsoft partner. "The cloud provides a way to make it easier to connect all of these different platforms and technologies, and my take is that Microsoft is trying to make Windows Azure the best and simplest place to run your applications regardless of the platform or technology."

The partnership may benefit Linux as well.

"There are customers who view Microsoft as their principal IT provider, and they will want to work with Microsoft," said Peter Chadwick, Suse senior product manager for cloud operations. "We've been working with Microsoft on interoperability, so this is a logical extension to that."