INDUSTRY INSIGHTS The Definitive Guide to Desktop Layering Gartner recently compared four methods of delivering applications in Virtual Desktop Infrastructure (VDI) and found application layering to be the best (see Selecting the Right Application Delivery Model for Virtual Desktops, Gartner Research ID G00269228, 09 October 2014). Gartner s analysis is boosting interest in this already-hot new desktop management technology. With this latest validation, vendors are being quick to include their products in the layering category. However, to distinguish effective layering solutions from products that just check the box, IT organizations must understand what desktop layering is, and what essential requirements layering must meet if it is to truly overcome the challenges of delivering and managing Windows desktops in the cloud.
Desktop Layering Defined Layering is a new virtual desktop management approach that separates the Windows C: drive into distinct, virtualized components, or layers. Windows OS and Application layers are stored as read-only virtual disk files (VMDKs in VMware vsphere, VHDs in Microsoft Hyper-V) that can be shared by many virtual machines. The Personalization layer is a writable virtual disk file that is unique to each VM, capturing all desktopspecific settings, data, and user-installed apps. File system and registry virtualization technology merges assigned Windows OS and Application layers with a machine-specific Personalization layer to form a virtual C: that is presented to Windows as a single image. Layering enables every desktop component OS, Apps, and Personalization to be virtualized and separately managed. Once assigned to desktops, layers are merged to form a composite C: drive from which Windows boots. Layered desktops are provisioned through integration with leading hypervisors and accessed through integration with leading connection brokers. There are many benefits to this approach: One instance of Windows and every application to patch and update. Layers can be updated centrally as often as needed without affecting the contents of other layers. Disk space savings. The same virtual disk files are shared by many desktops, cutting space requirements upwards of 80% compared to thick-provisioned, full clone desktops. Full personalization, including user-installed apps. Persistent and non-persistent desktops are provisioned from the same layers, so both desktop types are storage-efficient and easy to manage. One management console. Separate tools for desktop provisioning, image management, application delivery, personalization, and disk space savings are no longer needed, thereby reducing VDI project complexity and risk and enabling Tier 1 IT staff to manage virtual desktops.
Essential Desktop Layering Requirements Now that desktop layering is defined, here are the essential requirements of an effective layering solution. 1. Layer everything including the OS. Desktop layering must be able to layer every component of the desktop above the hypervisor Windows OS, Applications, and Personalization. Some solutions only address personalization layering or application layering. These partial solutions ignore the part of the desktop that changes most often the Windows operating system itself. They are also incompatible with OSdependent applications such as Internet Explorer, since they are unable to resolve OS layer conflicts. Windows must be patched and updated frequently for compliance and security reasons. An effective layering solution must be able to package and deliver Windows as a layer to make OS patches just as easy as application changes, and to ensure that OS-dependent apps work without failures. the ease with which you can layer Windows, apply OS service packs and hot fixes, and layer Internet Explorer along with other OS-dependent apps. 2. Support layer interoperability. A key benefit of layering is to simplify desktop and application deployment for IT by enabling layers to be assigned to any desktop in any order or combination. Another key benefit is that the many applications and plug-ins that need to interoperate can do so, leveraging the fact that layered apps appear as if they are locally installed (not isolated like traditional app virtualization). Some layering solutions require that IT administrators artificially group apps that need to interoperate in the same layer. This re-introduces the very complexity that layering is supposed to eliminate. App delivery times will increase as IT professionals are forced to anticipate what apps need to be packaged together. Layer sprawl will occur to account for the many different app combinations that exist in the real world. An effective layering solution must be able to resolve conflicts between OS, App, and Personalization layers, adjust layer priorities, and merge deep Windows-specific elements such as the driver store and.net fusion keys. Only then will IT be able to put any app in any layer, assign layers in any combination to any desktop, and rest assured that the apps will just work, the same as if they were hand-installed on each virtual desktop. whether applications such as Microsoft Office,.NET applications, QuickBooks, and plug-ins in different layers can interoperate. 3. Layer any application. Broad application compatibility is supposed to be a major advantage that layering has over traditional approaches to app delivery such as application streaming or application virtualization. However, some layering solutions do not support all applications, and recommend delivering unsupported apps as part of the Windows image. Again, this re-introduces the complexity and
Windows image sprawl that layering is supposed to eliminate. Effective layering solutions must enable IT to package all applications, including those with boot-time drivers and system services, as well as those applications that must be running when a user is logged out. whether PDF writers, speech recognition and dictation solutions such as Dragon Naturally Speaking, printers, scanners, antivirus, video surveillance, Single Sign On solutions such as Imprivata OneSign, and connection brokering software such as Citrix Receiver and VMware Horizon View client can all be layered. 4. Manage the desktop lifecycle. Layering isn t just about delivering apps. It s about managing the lifecycle of a virtual desktop in ways that weren t possible in the world of physical PCs. Some layering solutions don t take this holistic management approach. Desktop break/fix, auditing, layer replication, and version management are not provided, with the expectation that third party tools will fill the gaps. An effective layering solution must be able to track all changes to OS, App, and Personalization layers, with full audit records for compliance. Administrators must be able to undo patching mistakes simply by rolling desktops back to an earlier version of any layer. Multi-site VDI deployments must be accommodated with distributed layer replication, so that layer changes made centrally can automatically be propagated to thousands of desktops. how easy it is to track updates to layers; repair user mistakes by reverting to earlier versions of the Personalization layer or by forcing ITcontrolled Application layers to take precedence; and undo patching mistakes by reverting back to earlier OS or Application layer versions. 5. Reduce management consoles to one. According to Gartner, complexity is the #2 enemy of VDI projects (see Is the Hosted Virtual Desktop Market Struggling to Grow?, Gartner Research ID G00259186, 09 April 2014). Layering should reduce complexity by enabling all desktop management functions to be simplified and operationalized through a single console. Some layering solutions require separate tools for disk space reduction, desktop provisioning, image management, and desktop break/fix. Others introduce new technical terms to mask technical deficiencies. This complexity is the reason that many virtual desktop deployments stall, or require Level 2 and 3 IT resources for day-to-day management. An effective layering solution provides all VDI management services in one, easy-to-use solution that can be mastered by Tier 1 IT staff. whether service desk staff and Tier 1 IT administrators can perform all of the functions that are required to operationalize the day-to-day management of virtual desktops.
Conclusion Layering is more than a marketing term. IT professionals looking to overcome the challenges of desktop and application delivery and management in the cloud should consider these requirements when considering or evaluating a layering solution. Unidesk Corporation, 313 Boston Post Road West, Marlborough, MA 01752 USA Tel 508.573.7800 www.unidesk.com Copyright 2014 Unidesk Corp. All rights reserved. This product is protected by U.S. and international copyright and intellectual property laws. Unidesk is a registered trademark of Unidesk Corp. in the United States and/or other jurisdictions. All other marks and names mentioned herein may be trademarks of their respective companies. Item No: UNI-WP-LAYER-12-14