How Virtualization Affects Software Licensing
Posted on Thu, May 26, 2011 @ 07:54 AM
Traditionally, to stay compliant with software licenses, you simply had to understand your endpoints, and how to accurately license them. Often, the biggest decision was whether to license by user or device, and after that it was just a matter of accurate record keeping, license renewals and upgrades.
However, because virtualization changes your infrastructure, enables users to connect from many different types of endpoints, and changes how licensed applications are stored and accessed, licensing in virtualized environments is much more complex.
To remain compliant, it’s critical to clearly understand how virtualization affects software licensing.
Server Virtualization
Server virtualization is probably the least complex type of virtualization to understand from a licensing standpoint. At the core, you simply need to understand the number of servers you’re going to virtualize.
When dealing with a standalone virtualized server environment, this is pretty simple: count the number of virtual servers you have, and license accordingly.
Where it becomes more complex is when the servers are clustered for high availability or optimized performance. In clustered server environments, because virtual servers move between two or more physical servers, you have to license each physical server to the maximum number of virtual machines that could run on it.
To simplify: Say you have 10 virtual servers.
- In a standalone environment, you need 10 licenses.
- In a clustered environment with two physical servers, your virtual servers will move between these two machines. If one machine were to go down, all 10 virtual servers would have to run on the other. And, since you never know which machine might fail, you need to license each one for all virtual servers — meaning you’d need 10 licenses for each physical machine, or 20 licenses total in this case.
Desktop Virtualization
In desktop virtualization, the biggest thing you need to consider is: How are the endpoints changing, and how does that affect licensing?
When you virtualize your desktop environment, you’re essentially removing the OS from individual endpoints and placing it on a server in the data center, and then allowing endpoints to access it remotely.
The hard truth with licensing, though, is that even if you want to move your OS to the data center, you may not have the legal right to do so under your current licenses, which typically have a clause that the OS cannot be removed from its hardware home. To remain compliant, you’ll likely need software assurance or VDA subscription licenses.
Software Assurance or VDA?
Software assurance gives you the right to virtualize your OS, and your best bet is to purchase it within 90 days of procuring a new device running a Windows OEM license. After 90 days, you’ll have to do a software license upgrade that includes software assurance, or subscribe to a VDA license.
VDA (Virtual Desktop Access) subscription licenses are required for endpoints that can’t have software assurance, such as thin clients, iPads or other machines without a native Windows OEM OS. Remember, though some thin clients have a Windows XP embedded OS, if it’s not an OEM OS, you’re going to need VDA licensing.
One thing to keep in mind about VDA: it is not a perpetual license, but rather a subscription — meaning that your organization will incur ongoing costs.
Lastly, if your company is large enough, you might consider Microsoft’s Enterprise Agreement, which allows organizations to license both on-premise software and online services within one overarching agreement — ideal for large virtualized or cloud-based environments.
Application Virtualization
One of the more common environments that we see for virtualized applications is using Citrix XenApp with Microsoft Windows OS and terminal services. Licensing in this scenario is complex due to differences in how each vendor manages licensing structures.
- Citrix uses a concurrent license model, meaning that the number of licenses you have to procure is based on the maximum number of people that may access the server at a given time.
- Microsoft, in contrast, requires individual licenses for all users — or devices — that may access the software. In addition, due to the virtual access itself, Microsoft requires a remote desktop services CAL (Client Access License) for every user or device in your environment.
So, to remain compliant in this situation, you need the proper number of Citrix licenses to support your user base, along with individual CALs for each user or device that may access Microsoft applications running on the server.
Though Microsoft licensing makes virtualization more challenging from a business point of view, surveying your usage and licensing structure is critical to ensure that your organization remains in compliance.
Your Thoughts?
Have you run into licensing obstacles when deploying virtualization at your organization? How did you overcome them? We’d love to hear your experiences.
Liann Moser, MCPc's Licensing Business Development Manager, is an MCP (Microsoft Certified Professional) in enterprise, and small and medium-sized business licensing solutions. She has worked with all sizes of organizations in a variety of markets, including Fortune 500 companies, to develop licensing strategies. Connect with Liann on LinkedIn.
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