Organizations that want to use virtual desktop infrastructures inevitably hit a wall when they start examining their licensing choices. Microsoft's insistence on licensing its desktop operating system only for physical devices is clearly out of touch with the age of virtualization.
Where does an organization get a license for the operating system it wants to run in the virtual machine? And how does it license user access to virtual machines from the local computer?
Microsoft and its resellers generally push customers toward the virtualization benefits they can get by adding Software Assurance (SA) to their desktop operating system licenses through companywide licensing programs such as enterprise agreements. For customers that already have SA, the virtualization benefits are substantial -- the right to install Windows on unlimited virtual machines (VMs) and run up to four at a time, for about $55 a year per desktop, compared with the $150 cost for a single Windows Professional OEM license.
Microsoft customers can't just go out and buy a Software Assurance subscription; SA can be purchased only with a new license. Therefore, the customer must first buy a new copy of the OS -- even if that means buying another copy of Windows 7 for a computer that already runs Windows 7.
Only then will Microsoft let the customer pay the $55 a year for Software Assurance. The bill could exceed $300 per desktop over a three-year period. The vendor also restricts retail and OEM licenses to a single copy per physical device.
There are ways to reduce the cost, however, including alternatives that range in price from free to about $100 a year. In addition, organizations may be able to amortize the cost of the OS in one VM over multiple users, reducing the cost per user.
The two most common drivers for desktop virtualization are reduced desktop management and a need to run applications that are not compatible with Windows Vista or Windows 7.
Defining the requirement is important because the virtual licensing options involve tradeoffs. Be clear upfront about your goals to help your organization decide whether it can live with the alternatives.
In a desktop management scenario, a long-term approach will cover most or all of the organization's desktops. An application-compatibility scenario may have shorter and more focused goals: Only a subset of users and applications need to license virtual environments.
Windows XP Mode
The obvious solution for organizations that want virtual machines to handle legacy applications is Windows 7's XP Mode. It's a remarkable concession and the first time that Microsoft has given away a second OS license to customers. Microsoft lets customers with Windows 7 Professional run a free copy of Windows XP in Windows Virtual PC, which is also free.
This solution will likely be adequate for short-term virtualization of legacy applications in midsized firms and for specific departments.
The Remote Desktop option
The next virtualization option comes with every computer running a business OS such as Windows XP Professional, Vista Business or Windows 7 Professional.
It's called the Remote Desktop right, a name easily confused with the new name for Windows Terminal Services -- Remote Desktop Services (RDS) -- but it's not at all the same thing. The Remote Desktop right is part of the end-user license agreement that comes with every new computer running a business OS, and it gives users two ways to access a remote computer whether it's physical or virtual.
First, if someone is the primary user of the remote computer, he can access it from any other computer, regardless of what OS that other computer is running. For example, if user has a desktop running Windows 7 in his cubicle, he can freely access that computer from any other computer or device. No further license is required.
Second, any other computer with the same OS license can access that computer without requiring an additional license or SA. (Licenses may be needed for applications like Office that are running on the remote computer or VM.)
This right covers access to the remote operating system, but not the license for the OS itself in a VM. Thus, a bank of computers or blades with OEM licenses for a business OS can be remotely accessed by any computer licensed for the same OS.
This solution can suffice when an organization needs to run a small number of XP-only applications that are used occasionally by a specific department. By purchasing just enough copies of the OS to handle peak demand, the cost can be amortized over a large number of users.
Since the OEM version of Windows 7 Professional includes a license for Windows XP, VMs created this way can use XP instead and can be accessed by users who are licensed for either Windows XP or Windows 7.
Remote Desktop Services
The newly renamed Terminal Services is a time-tested solution for running remote desktops for either application compatibility or centralized management, and should not be overlooked as a virtualization option.
An RDS Client Access License (CAL) can be used to access a Windows 2008 R2 Server (capable of running Windows 7 applications) or a Windows 2003 Server, which may run XP-compatible applications better.
This CAL also licenses two other useful features. First is the connection broker functionality of Windows Server 2008 R2, which can link desktop users to an appropriate RDS session or to a remote physical or virtual machine. Second, it licenses App-V for Terminal Services, which streams applications to RDS sessions while isolating them from other applications. Since not all apps run well in RDS sessions, this improves compatibility.
At a one-time cost of $85 or less, per device or user, the RDS CAL is relatively inexpensive, although it may require additional hardware, particularly server memory, as well as additional Windows Server licenses.
Virtual Desktop Access
While not the cheapest virtualization solution, at $100 a year, Microsoft's Virtual Desktop Access (VDA) license offers a lot of flexibility for organizations that want to target limited virtualization requirements. It can also reduce other costs -- by letting customers run Windows instances on diskless PCs, for example -- thus netting out lower than its nominal cost.
A VDA license can be purchased for any device, including a thin terminal or a Linux desktop, and it offers SA-like virtualization rights: unlimited creation of VMs, connecting to four VMs at a time on the server and running an OS instance in a VM on the local machine. It even allows the use of "roaming rights" to run one copy of Windows in a VM (such as a VM stored on a flash drive or DVD) on a kiosk, a home PC or some other device not owned by the VDA licensee.
Adding Software Assurance
Two licensing workarounds let customers bypass the rule that they can buy SA only with a new license.
The first is to add SA to the OS license on a new computer licensed for Windows 7 Professional within 90 days of its purchase. By replacing old hardware with a new Windows 7 Professional machine and adding SA, which will cost $55 a year or less, the organization gains very liberal SA rights and can upgrade users who need to run XP-only applications.
The second solution is to license the OS through a subscription licensing program such as Open Value Subscription ($70 a year per PC with fewer than 250 computers; $61 a year per computer for more) or an Enterprise Subscription Agreement ($55 a year for more than 250 PCs).
These programs not only let the organization immediately upgrade all of its existing computers to the latest Windows version without buying full upgrade licenses, but they also give every PC full SA benefits, including virtualization rights.
Microsoft's licensing programs can help organizations that want to make a big commitment to virtual desktop infrastructure. They can reduce desktop management costs by running most or all Windows instances in VMs.
ABOUT THE AUTHOR
Paul DeGroot is a writer, trainer, and principal consultant at Pica Communications, which specializes in Microsoft licensing strategies and policies.
This was first published in January 2011