Friday, January 30, 2009

Windows Vista Virtualization: What You Need To Know To Get Started

By Danielle Ruest and Nelson Ruest

Microsoft's release of Windows Vista and its Service Pack 1 coincides with one of the greatest revolutions in the IT industry: the coming of virtualization technologies. VMware, Oracle, Citrix, Symantec, Sun Microsystems, Thinstall, Microsoft, and others have entered the fray to release products that are oriented towards virtualization.




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Running Windows Vista through desktop virtualization.

These products fall into two main categories.

  • Machine virtualization lets you run complete operating systems within a virtualized layer on top of physical hardware, making better use of hardware resources. This level of virtualization is proving to be a boon to organizations at many levels seeking server consolidation, desktop virtualization, disaster recovery planning, and more.
  • Application virtualization lets you "sandbox" applications so that they do not affect the operating system or other applications when deployed to a system. Application virtualization, or AppV, will make it much easier to manage application lifecycles because applications are no longer "installed" on systems, but rather, copied to systems.

Both of these technologies have a significant impact on Vista adoption. Overall, it is a good thing most organizations haven't moved to adopt Vista yet because they will be able to take advantage of virtualization in their deployment. Here's how.

Use Machine Virtualization With Vista

A major barrier to Vista adoption is the hardware required to make the most of its feature set. While the base hardware requirements for Vista are not too unusual, considering the type of hardware that is available now, they are still important. Hardware refreshes are expensive, so whether you have 10 computers or 10,000, you need to plan and budget for hardware refreshes.

The table below outlines two sets of requirements for Vista: Vista Capable and Vista Premium PC configurations. The first allows you to run the base-level Vista editions and the second lets you take advantage of all of Vista's features.

Vista Capable PC Vista Premium PC
Processor At least 800 MHz 32-bit: 1 GHz x86; 64-bit: 1 GHz x64
Minimum Memory 512 Mbytes 1 Gbyte
Graphics Processor Must be DirectX 9 capable Support for DirectX 9 with a WDDM driver, 128 Mbytes of graphics memory*, Pixel Shader 2.0 and 32 bits per pixel
Drives DVD-ROM drive
Accessories Audio output
Connectivity Internet access
* If the graphics processing unit (GPU) shares system memory, then no additional memory is required. If it uses dedicated memory, at least 128 Mbytes is required.

If you want to plan for the future, you should really opt for a Vista Premium PC. But what if you didn't have to be too concerned about hardware upgrades and could still have access to Vista's features? That is what machine virtualization can do. In fact, the common term for this process is desktop virtualization.




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A virtual machine is really just a series of files in a folder.

With desktop virtualization, you run Windows Vista inside a machine virtualization engine on a central server. Then you give users access to a virtual version of Vista through a remote connection. Users can continue to run older Windows operating systems on their actual desktops, but, through the remote session, access and use the new Vista feature set.

It is fairly easy to do this and you don't necessarily need a server to host the virtual Vista instance. Lots of manufacturers now offer machine virtualization technologies. What is even better is that many of these technologies are completely free! For example, Microsoft offers Virtual PC and Virtual Server 2005, VMware offers VMware Server, and Citrix offers XenServer Express, all for free. Others such as Oracle and Sun both offer free virtual machine engines -- Oracle offers Oracle VM and Sun offers xVM -- but their engines are not optimized for Windows operating systems, so you won't gain by using them for this purpose.

Of the three that do run Windows properly, the best choice might be Citrix XenServer Express since it is an operating system in and of itself. With the Microsoft and VMware offerings, you need to first load a supported OS on the host system, then load the virtualization engine. With XenServer, you just load XenServer, then create the virtual instances of the operating systems you need.

This arrangement can offer the best of all worlds. Here's why:

  1. When you run Windows Vista on a system, server, or PC, you need a license. All retail Vista licenses only allow one single instance of the operating system to run for each license. The Enterprise Edition, however, offers up to four virtual instances of Windows Vista for each license you own. Note that the only way to acquire the Enterprise license is through a Software Assurance program. This is often out of reach for small to medium businesses.
  2. If you use the Microsoft or VMware virtualization engines, you'll need a license for the OS running on the actual hardware system if you choose the Windows version. Then you'll need a license for each instance of Vista you want to run in a virtual instance.
  3. With VMware Server, you can choose the Linux version and run a "free" operating system on the hardware system. Microsoft does not offer a Linux version of its virtualization products.
  4. If you use XenServer Express, then you just need to load it onto a hardware platform. From then on you can create any instance of Windows Vista. Of course, each instance of Vista will require a license.

Whichever solution you choose, you'll gain lots of advantages by running Vista in a virtual machine. First, if you run it from a server, you can provide central backup and control of each machine. Second, because a virtual machine is really nothing but a series of files in a folder, it becomes really easy to create multiple machines; just copy the files and you have a new machine. Third, it becomes so much easier to protect machines because each machine is contained within itself. For example, if a virus attacks a virtual machine and corrupts it, just throw the virtual machine away and restore it from a backup. Voila! You're back to a working machine in no time. And finally, because the resources required to run the virtual machine are on the server or host machine, you don't need powerful resources at the endpoint to run Vista.

There is no doubt that machine, or rather desktop, virtualization is an attractive solution for a Vista migration. It might even be an attractive solution for the home user since you can use it to "sandbox" each Vista session and therefore protect all others. However, this is only really viable for the experienced home user.

You'll also need to keep in mind that the license for Windows Vista Home and Home Premium does not allow home users to run them in virtual machines. If you intend to use Vista in a virtual machine, it must be one of Business, Ultimate, or Enterprise and obviously, the latter wouldn't be available to home users.


Use Application Virtualization With Vista

A second major barrier to Vista adoption is application compatibility. Microsoft has modified several core components of the Windows code with Vista and, in many cases, this breaks applications. (See How to Manage Windows Vista Application Compatibility.)

If you decide that you don't want to centralize all your desktops and intend to deploy Vista on each one of your endpoints, then perhaps you need to take a really close look at application virtualization (AppV). AppV is much like machine virtualization, but instead of capturing an entire operating system installation, it captures each and every application you deploy on your systems. Basically, you "sandbox" each application so that it does not make any actual modifications at all when it runs on a system. This is all done through the use of an application virtualization agent that resides either within the application itself or on the operating system.

The single most powerful advantage AppV gives you is that, once an application is virtualized, it will run on any Windows operating system. Just think of it. Each time you move from one OS to another, you have to test all your applications, repackage them to meet target OS requirements, and then deploy them.

With AppV all that goes away since, once the application is virtualized, it will run on any Windows OS. And, because there are no changes to the target OS, you do not need to install the application, but rather simply copy it to the system. That's because AppV does not capture the application installation process like other systems do, it captures the running state of the application. That's powerful and may even warrant the adoption of AppV even if you don't migrate to Vista.

Like machine virtualization, several vendors have released AppV engines. Microsoft offers Application Virtualization 4.5. Symantec offers Software Virtualization Solution (SVS) through its Altiris division. Citrix offers AppV through Citrix XenApp (formerly Presentation Server 4.5). Thinstall offers ThinstallVS. Of these, only Symantec offers a free or personal edition of its AppV engine. This personal edition of SVS is fully functional and can be run on up to 10 PCs. What's even better is that the download site also includes over 40 pre-virtualized applications.

In many ways, application virtualization is even easier to use than machine virtualization. With AppV, the only thing you need to change is the model you use for application management. Home users can virtualize anything from Internet Explorer to full versions of Microsoft Office. Don't like what a recent Web site visit has done to your browser? Just reset the application and you're back to what you had before. This might just be the answer to what your kids need on the home PC.

Imagine, since Symantec's SVS is free for personal use, home computer manufacturers could pre-load it on their systems. Then, you could carry your applications around with you on a USB keychain. Want to do a bit of browsing, just plug in your USB and launch your favorite applications. Not that's something everyone can get their teeth around.

In the office, AppV is even more powerful. We've worked on a ton of migration and deployment projects and we know for a fact that the most time-consuming effort in any such project is application preparation. With AppV, you completely change the dynamics of any deployment project and put all of the application woes behind you. That's a powerful operating model.

There you have it: two different models that can let you move to Windows Vista at your own pace and on your own terms. Now there's no reason to delay. Move to one of the virtualization models first, then you can move to Vista once you've mastered these new IT operating models.

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Posted by Roy Zafar at 8:34 AM

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