Every enterprise customer that I work with uses Provisioning Services for XenApp and Pooled VDI in order to take advantage of all the management, storage and performance benefits.
However, the majority of these customers end up having to manage multiple images (sometimes >10). In most cases, applications are locally installed. In a few others, App-V is used in conjunction with locally installed apps. In rare instances, SCCM/LANDESK and similar ESD tools are used.
For Pooled desktops, it’s–for the most part–a combination of locally installed apps and apps delivered via XenApp. Sometimes, third party tools are also used. The net result is that multiple dedicated resources spend most of their time updating these images and managing application updates.
So, what does XenApp/XenDesktop 7.8 offer to solve this problem?
I seem to constantly have discussions with my customers around how to solve the problem of image management, and it usually boils down to separating the applications from the operating system as far as possible.
XenApp/XenDesktop 7.8 introduces AppDisk, which provides the ability to manage your applications independently of the base image.
AppDisk falls under application layering, which has been around for some time. You can add any number of applications to an AppDisk and the AppDisk can then be tied to multiple machines at the same time. These machines can be running different operating systems. So if you are an Enterprise customer that has multiple XenApp silos today–due to different business units requiring different applications–and have multiple PVS images that you manage for this purpose, you could potentially cut down to one image for each OS and then use AppDisk to layer the applications.
The result is that it makes the management of the images a lot easier. Not only that, application updates become a lot easier and the maintenance windows will reduce significantly. Also if you wanted to replicate your applications across multiple datacenters, it is as easy as copying these AppDisks over.
Integration of AppDisk with AppDNA
There are a number of vendors today that offer layering solutions, including some that partner with Citrix. What truly differentiates AppDisk is our integration with AppDNA. When there are multiple layers tied to a delivery group for instance, AppDNA lets the administrator know how a change in one layer could potentially impact compatibility between other layers. This will allow administrators toreorder the layers if needed.
Similarly, AppDNA can also inform the administrator if an AppLayer is incompatible with a specific OS. So, if I were to tie the same AppDisk to multiple delivery groups delivering different operating systems, thanks to AppDNA, you can quickly determine if that AppDisk is compatbile with the target OS. This is truly a differentiator and removes a lot of the guesswork and manual labor involved in compatibility analysis.
With all that said, layering is not a one size fits all solution for application deployment. There are various challenges. When you use mutiple Appdisks, it is important to have an understanding of the dependencies between layers to make sure the layers can work with each other and there are no conflicts. In large environments, there could be hundreds of layers, each layer having a large number of applications. Management could get complex in those cases. Also, AppDisk is not supported on dedicated desktops today. Another thing to keep in mind is that PvD and Appdisk cannot be used together today
Another key feature in XenApp/XenDesktop 7.8 is the ability to publish App-V packages that are stored in a network share without needing the App-V infrastructure. The process is no different from publishing a natively installed application. So why App-V? There are a couple of reasons. First, AppDisk does not provide application isolation. Therefore, if you require application isolation, in order to run multiple versions of the same application for example you would need to use a technology like App-V. Secondly, if you already have your desktop teams leveraging App-V to sequence packages, it makes sense to deploy the same packages within your Citrix environment instead of reinventing the wheel.
It’s human nature to be enamored by the latest shiny toy. But in the case of application management, there is no one size fits all solution. With the XenApp/XenDesktop 7.8 release, there are various new options available for packaging and delivering applications. Does that mean the tools we provide will address 100% of the use cases out there? Probably not. We have a number of partners who add further value through their solutions. Fine examples are Liquidware Labs, FSLogix and Unidesk.
I believe that a lot of enterprise deployments will continue to deploy core applications natively in the base image, either locally installed or using App-V and the likes. However, AppDisk with AppDNA is a great solution to manage business unit specific applications that were silo’d in the past and increased the infrastructure and operational overhead substantially. To conclude, I would highly recommend that you try XenApp/XenDesktop 7.8 in a lab environment and get familiar with AppDisk and App-V package deployment.