Virtual desktop infrastructure (VDI) takes advantage of an existing virtualization infrastructure, using the same hypervisor as the virtual servers in your virtualization environment to virtualize a desktop.
As the old concept of server-based computing makes way for an application-first approach, you can take the skills you've developed to host virtual servers via hypervisors, such as Microsoft Hyper-V, and use them for other, more user-centric purposes as well. And the long-standing partnership between Citrix Systems, Inc. and Microsoft is well positioned for this new approach.
If you've read my articles over the past few years, you may already know that I'm not a fan of VDI (also known as hosted virtual desktops). To paraphrase TechTarget writer Brian Madden, "VDI is a great way to take a 100-user Terminal Services box and turn it into a 10-user VDI box."
But even during my most vitriolic anti-VDI rants, I've always said that a
- It eliminates the application compatibility problems that some programs have with Terminal Services or Remote Desktop Services (RDS);
- It gives users a real and independent workspace that can't be achieved with Terminal Services, RDS or XenApp; and
- It's useful in labs, call centers and other environments that need rapid turnover of machine instances.
Virtualization technologies and computer templates enable much of this VDI optimization.
Today, we have seen a sea of change in VDI technologies, with old partners re-engaging for an eerily-similar solution set. Again, that set focuses on access as the primary business motivator. This old-but-new approach is predicated on the simple fact that users need access to their applications and data. They also need easy-to-use solutions that function and don't dramatically change their daily workflow.
At the same time, you need to provide these solutions in the most cost-effective manner. In the end, your company doesn't care whether it does its work through hosted desktops, RDS sessions or something entirely different. It just needs to do business.
VDI implementation as an option
One of the prevailing limitations of a VDI implementation stems from the variety of parts that must integrate together. Consider the following:
- a hypervisor platform to handle virtualization;
- a transport protocol to deliver the desktop to the user;
- a broker to route each user to the right desktop or published application; and
- personality management tools that inject user profiles into each session.
Traditionally, getting these pieces to work together has been a big hurdle with and early VDI implementation. Often, it requires a mishmash of solutions from numerous vendors.
This creates another set of problems. Having difficulties with your stack? You'll find vendor A pointing the finger at vendor B, and vice-versa. If you're a systems integrator, getting them these technologies to work in a way that saves rather than costs money can be hugely problematic.
But here's where the long-standing partnership between Citrix and Microsoft has the potential to shine. Microsoft has always been an operating system company, with the corporate willpower to design the right OS for the business sector. And Citrix has a history of delivering OSes through the wire with the best performance and management features that enterprises require.
So together, VDI and the Microsoft Hyper-V--plus-Citrix-XenDesktop architecture create an interesting dynamic. Microsoft Hyper-V R2 is an enterprise-worthy platform, whose low deployment cost reduces barriers to entry.
Citrix, on the other hand, has a long history of enabling access to any device anywhere and anytime. Its single-minded focus on access layers on top of Microsoft's OS provides a foundation for an affordable and scalable infrastructure.
Another benefit of combining Microsoft virtualization and Citrix VDI is that you're not limited to VDI. The Microsoft-plus-Citrix stack for hosted desktops also enables an infrastructure to run applications on top of Remote Desktop, XenServer or another session-based technology.
It's well-established that session-based applications running on top of Terminal Services, RDS or XenApp tend to net a higher user count per server than VDI architecture. Moreover, some applications don't work well in a session-based environment. Leaning on a Microsoft-plus-Citrix stack for VDI means that you can deploy application access in ways that make sense for each program -- whether as hosted desktops, streamed applications, or applications atop Terminal Services, RDS, or XenServer.
This results in a much smarter use of your precious hardware resources. Dedicating the right amount of physical resources in the proper places creates pervasive application access by using several approaches at once.
And, in the end, isn't that what your users want?
Greg Shields is an independent author, instructor, Microsoft MVP and IT consultant based in Denver. He is a co-founder of Concentrated Technology LLC and has nearly 15 years of experience in IT architecture and enterprise administration. Shields specializes in Microsoft administration, systems management and monitoring, and virtualization. He is the author of several books, including Windows Server 2008: What's New/What's Changed, available from Sapien Press.
This was first published in January 2010