Desktop virtualization aims to lower the costs and increase the security of desktop computers, but agencies must determine which approach — or combination of methods — best suits their needs.
Maintaining employees' computers is one of the information technology department’s most thankless responsibilities. The desktop and laptop PCs that are fixtures of today’s workplace eat up IT staff time and a good slice of the department’s capital budget. But usually, the IT department hears from users only when the devices are broken or tied to a security breach.
Desktop virtualization technologies probably won't make users any more appreciative, but by centralizing desktop administration tasks in the data center they can lighten the load on the IT department while enhancing security. Estimates on the potential cost savings vary widely because the upfront costs for buying virtualization systems or upgrading existing infrastructure such as networks to support it shift depending on the would-be implementer’s situation. But analysts do agree that overall costs will come down in the long run, sometimes significantly.
Part of that challenge is that agency leaders have to sort through several virtualization options, and choosing the best one — or a combination — for each unique situation can be difficult.
Desktop virtualization aims to simplify desktop computing in much the same way as its better-known sibling, server virtualization, lets agencies cut fat in the data center by running multiple virtual machines on a single physical one. Fewer servers means less hardware and lower support costs.
Desktop virtualization doesn’t eliminate computers from users’ desks, but it does allow workers to get by with less expensive, stripped-down models or even older, re-purposed units. The technology transfers a lot of PCs' brains and data storage to central servers in the data center, where IT staff members can manage them more efficiently, including keeping them up-to-date with security patches.
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Government has been broadly adopting server virtualization, which is now a fairly settled and mature technology. The desktop variety, in contrast, presents a more varied landscape. Indeed, buyers face multiple technical approaches to desktop virtualization. Those flavors, in turn, feature different levels of customer adoption and offer different potential benefits.
The task for customers is to determine which desktop virtualization approach — or combination of methods — best suits their needs.
“A lot of people are wrestling with that these days,” said Joe Brown, president of Accelera Solutions, an IT solutions provider that specializes in virtualization and works in the government market.
Here’s a rundown on the main forms of desktop virtualization.
Option A: Presentation virtualization/application virtualization
How it works
Presentation virtualization lets users share an application hosted on a central terminal server. Instead of having expensive, full-functioning PCs on their desks, users have thin clients, which are stripped-down computers with no hard drives. The servers handle the data storage and the bulk of the application processing action, save for the user interface, which runs locally on the user’s desktop machine.
Microsoft’s Windows Terminal Services and Citrix Systems' Presentation Server — now rebranded as XenApp — are examples of the approach.
Such presentation solutions are simple to deploy as long as adequate network bandwidth is available, said Jim Smid, data center practice manager at Apptis Technology Solutions, an integrator with many government customers.
Brown said Citrix’s technology, in particular, has proven an effective solution for delivering a standard application to a large group of users who have regular network access. He said this approach can cover the desktop application needs of 30 to 40 percent of a typical organization’s users.
In the past, presentation virtualization wasn't an option for users who don’t have regular network access. But vendors have added a new capability called application streaming or application virtualization that address this mobile population. Citrix’s XenApp, for example, can deliver a mobile version of applications to workers’ desktops while they are connected. They can then run that application later even when there is no network connection.
VMware’s ThinApp and Microsoft’s App-V also offer application streaming.
Where it fits
Presentation virtualization and application virtualization play different roles in an organization.
Presentation virtualization sees the greatest use among task workers who use a limited number of standard applications, such as in call centers, said Tom Simmons, area vice president at Citrix's Government Systems division. Another niche is presenting existing applications that are difficult to manage on the client side.
It is also a good choice for users who need standard applications that access large, centrally stored datasets, said Rhys Ziemer, a technology expert at Microsoft.
Meanwhile, application virtualization and streaming provide centrally controlled and distributed apps to users, whether they are in-office workers with constant network access or mobile workers with only occasional network access.
Industry executives identify presentation virtualization and application virtualization as the most common forms of the technology. They said the ability to centrally manage applications and meet security standards, such as the Federal Desktop Core Configuration, rank among the attractions in government.
FDCC, a mandate of the Office of Management and Budget, calls for agencies to introduce standard configurations of Windows XP and Vista PCs in an effort to boost security.
Option B: Virtual desktop infrastructure (VDI)
How it works
VDI represents a newer development in desktop virtualization, and it is just now emerging among government agencies. The technology also falls under the hosted virtual desktop label. VDI Products include Citrix's XenDesktop, Parallels’ VDI and VMware’s View.
Microsoft, meanwhile, provides a basic, manageable VDI infrastructure with its upcoming Windows Server 2008 R2, Rhys said. General availability is slated for later this year.
The hosted virtual desktop approach is an effort to centralize user computing. Although a traditional PC houses the operating system, applications and data on a local hard drive, a virtual desktop places those elements in the data center. Each user’s desktop is maintained as a virtual machine running on a central server. A server could potentially host thousands of such virtual desktops for an agency's user population.
A connection broker, which supports one or more remote viewing protocols, links the user to his or her virtual desktop. Virtualization software vendors offer connection brokers, and third-party brokers are available from companies such as Leostream and Quest Software.
An organization might choose to use a conventional PC — a thick client — to display the virtual desktop or opt for a smaller device, such as a thin client or even an older model PC.
Where it fits
VDI offers greater opportunities for customizing the user experience compared with shared presentations of server-based applications.
Each virtual desktop residing in the back-end server infrastructure exists independently of all others. This isolation gives all users “their own personalized desktop,” said Raj Mallempati, group product manager for desktop solutions at VMware.
Accordingly, Brown said he recommends hosted virtual desktops for users who need personalization capabilities that a shared platform wouldn’t provide. He added that virtual desktops also avoid some application compatibility issues found in shared-computer environments.
VDI might also prove to be a fit for organizations that seek to maintain traditional desktop capabilities such as bi-directional audio/video and streaming video that are difficult or impossible in a shared presentation form of virtualization.
“As much as possible, we completely replicate the physical environment by doing things like bi-directional audio and video,” said Paul Garver, vice president of Quest Software's public sector division.
For the most part, VDI has surfaced as proof-of-concept deployments in government. But larger deployments have begun to emerge.
At the U.S. Patent and Trademark Office, 2,110 production employees — including trademark attorneys and Board of Patent Appeals judges — use a virtual machine for desktop computing, an agency spokeswoman said. USPTO’s desktop virtualization is built on VMware’s server and desktop products.
Elsewhere, Pike County Schools in eastern Kentucky has adopted a virtual desktop approach using IBM’s desktop cloud service. IBM hosts the VMware-based virtualized infrastructure, which spans 1,500 client machines.
Students access virtual desktops from an array of computer devices, including many older desktop models. “We can bring them back to life — kind of like Frankenstein,” said Marrita Horne, Pike County Schools' technology director.
District officials hope to add 2,000 more computers to the virtual service, including older machines that otherwise would have been scrapped. Horne also noted improved security as another advantage for the virtual desktop environment.
Option C: Virtual desktop/client-side hypervisor
How it works
In this wrinkle, the virtualization software operates only on a user's PC. This technology lets users operate virtual machines on their own devices as opposed to relying on a server to do the virtualization chores.
VMware set the market in motion in 1999, with the debut of VMware Workstation — the company’s first product. Workstation allows a PC to run multiple operating systems. Products in the Workstation mold are called Type 2 hypervisors because they run within an operating system. Type 1 hypervisors, typical of server virtualization, run directly on hardware.
However, some vendors are pushing Type 1 hypervisors to the desktop. Citrix’s Project Independence, in which it collaborates with Intel, marks one effort to develop a client-side hypervisor.
Where it fits
In recent years, products that let Apple Mac users run Windows or Linux have been a popular use of desktop virtualization. Parallels’ Desktop for Mac and VMware’s Fusion fall into that category.
The government has provided a steady source of users who want the ability to run Mac and Windows applications side by side. Bill Portin, vice president of sales and operations at Parallels, listed NASA, the National Institutes of Health and the Energy Department's national laboratories among the company's customers.
Aileen Black, vice president of VMware’s public-sector division, said Fusion is taking off in the Army, which recently purchased 7,500 Macs. The Defense Department and intelligence agencies have also requested it, she said.