Citrix / Unidesk — Application Layer: Check; Personalization Layer: ?

In January, Citrix announced the acquisition of Unidesk. There has been tremendous excitement about this addition to the Citrix portfolio.

As you may recall, Citrix attempted application layering technology on its own in early 2016. As part of XenApp/XenDesktop 7.8, Citrix released AppDisk, but it never really caught on because there were several third-party products that addressed app layering more effectively. AppDisk is being retired in favor of the new Citrix App Layering (Unidesk) functionality. There is no defined upgrade path from AppDisk to App Layering, but that’s likely a minor issue because AppDisk adoption over the past year was quite low.

In early April, the Citrix-branded version of Unidesk—now named App Layering 4.1—was released. With the exception of the name “Citrix” inserted on the administrator interface, the product still looks and feels much like pre-acquisition Unidesk. For this new release, documentation has not yet transitioned to the Citrix eDocs website.

A key feature of the v4.1 release is Azure support. Citrix is continuing its push for “cloud first” as a key component of all its product release cycles, and Azure support in just three months is certainly a key milestone.

The Unidesk acquisition promised two key features: app layering and personalization. App layering seems to be alive and well, but what happened to personalization?

What Exactly Is App Layering?

To simplify the explanation of app layering, think of it as “bolt-on” layer of one or more applications. Each layer is affixed to the base image, enabling an organization to maintain just one or perhaps a few base operating system images, rather than one for each requirement. The goal is to then “bolt on” each of the layers as needed to address the business use cases.

One of the complexities of the new App Layering feature is the concept of the application layered image and the elastic layer. The key difference is that the former can be applied at preboot, whereas the latter is delivered during user logon based on specific users or groups. If it sounds complex to determine which one should be used when, that’s because it is indeed a fuzzy gray line.

When attempting to deploy elastic layering, the administrator is advised with a green/red icon whether it is successful. That is a bit frustrating, because elastic layering must first be attempted, and thus the administrator has expended time on an option that may or may not function.

Personalization Layer

One of the promised capabilities, Personalization, is not included as a full feature in the 4.1 release. However, a beta of the Personalization feature for Windows 7 is available. Personalization is important functionality for XenDesktop administrators and the adoption of layering. Let me explain.

If a XenDesktop admin wants to maintain just one or a few pooled images and let users add applications and otherwise personalize their virtual desktops, Personal vDisk is often used, which is based on the former RingCube product. This is a separate disk that is mounted to the VDI image at startup and that can provide user personalization—i.e., user profile—and user installation—e.g., additional applications. The latter is key, because most commonly, Personal vDisk is used as the option that enables self-help for users so that they can install necessary applications that are not provided within the VDI image provided by corporate IT.

The benefit of Personal vDisk is that the Citrix administrator won’t be getting calls to add this application or that one because a single user in finance or sales or engineering has a special requirement. The downside is that users can go a bit crazy installing applications, and storage requirements can grow unexpectedly.

While Personal vDisk isn’t quite perfect, it’s conceptually a good solution that enables Citrix administrators to minimize the number of VDI images in use. When the Unidesk acquisition was announced, new capabilities to replace Personal vDisk were discussed. However, there is no production release for Windows 7 and, more importantly, Windows 10 as of today; thus, administrators must still use Personal vDisk.

To take it one step further, there has been no clear definition as to whether there will be an upgrade path from Personal vDisk to Unidesk Personalization. For example, if a user has installed numerous applications to a Personal vDisk and a transition process is not defined, those applications would likely need to be reinstalled into a new Unidesk Personalization layer. Explaining to Bob in Accounting that his specialized interest rate application and other self-installed programs that he uses daily need to be reinstalled to his new Personalization layer because IT is moving to Unidesk Personalization won’t be a pretty conversation. Until a solid go-forward path is defined for Personalization, including licensing entitlements, administrators who are currently deploying Personal vDisk are in a precarious situation.

The Unidesk acquisition is still generating tremendous enthusiasm and questions, because it has the potential to greatly simplify the administration of XenApp and XenDesktop environments and pave the way for more streamlined Citrix deployments. However, clarity regarding the Personalization feature is necessary before Citrix administrators will make the leap.

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