Tackling the Craziness: Microsoft Licensing Limitations on vMotion

Microsoft licensing. Those two words are often enough to cause even a veteran IT professional cringe. Typically, reading and fully comprehending a license document requires a law professor, Hoodini’s ghost, some tarot cards, and a nice strong shot of whiskey. One particular craziness is how Windows server licenses are tied to the underlying hardware, including virtual machines to the host running a hypervisor. All of the sudden, vMotion becomes “illegal” in some cases.

This is kinda what it is like to deal with Microsoft licensing

Who is Affected?

This issue doesn’t specifically stop at VMware’s vMotion. Seemingly any Windows server license falls under the agreement umbrella. It’s rather sad that in this day and age we’re still having to jump through hoops around licensing, although I would imagine profit margins come in to play here somewhere. I find it especially confusing since Microsoft has a product that is also hurt by this policy, and an ecosystem of overt complexity only breeds FUD (Fear, Uncertainty, Doubt).

Tasty and delicious

Working Through the Pain

I’ve always been a strong advocate of the Windows Data Center level licensing, as it seems to be extremely friendly to virtual environments. In a nutshell, Data Center is sold on a per socket quantity. Any Windows server using that socket is licensed and can use whatever edition needed. The price is typically competitive compared to the Enterprise license, which only allows for 4 guest VMs to be created per license. This doesn’t mean that you have to install Windows server Data Center edition (typically overkill for most people) in the virtual machines.

As an example, a two socket VMware host can run multiple copies of Windows server in all flavors (Standard, Enterprise, or Data Center) as long as two licenses of Windows Data Center are purchased.

Unless you already have a significant investment in lower level licensing, such as a server farm running non-OEM’ed Standard licenses, go with Data Center.

Note: I specifically leave out anyone with an enterprise agreement with software assurance. I imagine that at that level, you aren’t worrying too much about licensing. 🙂

Big Brother Isn’t Watching You

Not that I’m advocating violating your license agreement, but to be clear there is no call home feature that I’m aware of that sends the five-O to your business. Definitely know what you’re getting in to before you crank up DRS to fully automated and let it play shuffleboard with your VMs, but don’t worry about events like HA restarting your VMs due to hardware failure (perfectly within your rights of the licensing).

If you are audited, though, you may be in for some fun. And by fun, I mean not fun.