As a Citrix SE and former Unidesk solution architect, I often worked conference booths giving demos and answering questions, so I got to talk to a lot of the IT people at a lot of IT shows. It is always interesting to hear what they’re being told by other layering vendors now that this idea of delivering apps as virtual disk containers is going mainstream, and others are offering their own layering solutions.
Some of the perceptions about layering were accurate. Many weren’t. Here are some of the things that the vendors are saying about layering in general that don’t apply to Citrix App Layering:
1. Layering technology can’t deal with apps that have early Windows dependencies like Dragon, Imprivata OneSign, antivirus, and agents like the Citrix VDA
Most layering solutions are based on architectures that run above the Windows OS and only do in-guest layering. Whether they attach apps at user logon or machine start, these solutions run too late to be compatible with apps that have deep Windows dependencies, boot-time drivers, system services, and pre-logon requirements. These vendors tell people, “layering technology cannot handle these types of apps. You have to put these apps in your base image.” Read VMware’s response in their App Volumes forum when one customer asked about layering Imprivata OneSign to see what I mean.
That is not the case with Citrix App Layering. We have the only “full-stack” layering technology that can manage and deliver the entire Windows workspace as modular virtual disks, including the Windows operating system itself. This unique architectural approach enables us to offer 2 kinds of layering that are compatible with all apps.
Layered Images are built before a machine boots using layering technology that runs outside the Windows guest. This out-of-band layering option lets admins combine a Windows OS layer and any combination of app layers into a full-blown image that can be delivered through existing provisioning technologies, such as Citrix Provisioning Services, Citrix Machine Creation Services, or even VMware Horizon View Composer. It works even when a user is not logged in. This type of layering starts early enough, so you can manage all apps independent of Windows, and avoid the cost of patching multiple Windows images. Antivirus. Internet Explorer. Imprivata OneSign. Dragon. XenApp VDA. VMware Horizon View agent. Citrix Receiver. They all work. This type of layering has proven itself for years with over 1,000 customers across various verticals managing these types of apps in production.
Elastic Layering was introduced in App Layering 4.0. This in-guest layering technology works by mounting assigned layers to a running Windows VM. As we showed at Synergy, we’re the only layering solution that can also hot-add apps at logon to individual XenApp and RDSH sessions, making XenApp shared hosted desktops look a lot like VDI (every user can have their own unique apps).
2. Layering requires you to group dependent applications.
Other vendors are just starting to learn about layer interoperability requirements and application dependencies between layers. So, they either create heuristics that require you to manually set or guess priorities, or they tell you to stack apps that need to interoperate in the same layer. Or, they tell you to place all similar apps (like .NET based apps) into a single layer.
The whole point of app layering is to enable helpdesk and Tier 1 IT staff to take on the bulk of app packaging. If they have to jump through all of these hoops, or develop line of business knowledge to know which apps MIGHT have to communicate with each other or have .NET dependencies, and therefore must be stacked together, you’re back to having your most expensive Tier 2 and 3 IT people doing app packaging and patching.
Citrix App Layering is the successor to Unidesk App Layering. It has been around since 2009 and is the result of years’ worth of customer feedback and testing. Customers had said they didn’t want complexity. They didn’t want to have to worry about packaging dependencies. They didn’t want to put their highest paid IT people on app management. They wanted to be able to layer any app on its own, assign any combination of apps to any machine or user, and know they would just work. An automatic layering priority mechanism and internal conflict resolution engines as part of our Cross Layer Merge™ technology to make sure apps — even the gnarliest.NET apps — just work.
3. Layered apps impact logon speed. That’s just the way it is.
This is true for the other layering solutions that only offer in-guest virtual disk attachment at logon. Every call to mount a VHD takes time, so the more layers you mount, the longer your logon times will be.
In Citrix App Layering, you have the option to choose how layers are deployed. In environments where logon times need to be optimized (think Clinical Heath Care environments), IT can choose to deliver the layers as part of a Layered Image instead of an Elastic Layer that is attached at logon. Apps in Layered Images are already merged, loaded, and ready to go before a user logs on. Therefore, you get the performance of a native application and fast logon speeds, without sacrificing package-once, patch-once efficiency for any of your apps. Citrix App Layering is the only solution that can do this.
4. All layering technologies integrate with Citrix Provisioning Services or VMware View Composer.
Not really. Other layering vendors assume you will still deal with image management and Windows updates outside of their layering solutions. To them, layering is a bolt-on tool that can only be used for some percentage of desktop apps. The rest of the apps have to be baked into multiple images and managed through existing image management and provisioning solutions like Citrix PVS and VMware View Composer. They don’t integrate with these tools. They just run alongside them.
Citrix App Layering actually integrates with these image management technologies. We enable you to layer all apps, agents, and software, including Windows itself. You pick the OS and app layers you want to create Layered Images from and let our connectors automatically deploy the images through PVS, MCS, View Composer, etc. One-off and departmental apps are assigned at logon based on AD user and group membership with our Elastic Layering.
When you need to patch Windows, you patch your OS layer once, and let the App Layering appliance update the images and push them through your existing image management solutions. Only Unidesk enables you to manage image CONTENT, and leverage your existing tools to do what they do best, which is manage image DELIVERY.
5. The ability to add layers at logon is the most important feature because it makes VDI and Session hosting more resource-efficient.
With Citrix App Layering, you only have to create 1,000 VMs (well, maybe a few more for headroom) to accommodate many more users and use our Elastic Layering to attach each user’s apps and personalization at logon. This enables you to give pooled, non-persistent desktops the look and feel of persistent desktops with a lot less resource and cost.
But while most layering technologies now offer this ability, we’ve even taken it one step farther than everyone else by providing this same capability for XenApp, enabling users logging on to the same XenApp server to have their own unique apps and personalization. XenApp shared hosted desktops are even more resource-efficient than non-persistent VDI, so your costs for personal Windows workspaces are even lower.
Yet even this isn’t the most important feature. App Layering was designed so that we’re never the bottleneck to scaling your environment. Our Layered Images get handed off to your existing provisioning systems, so Citrix App Layering will scale as large as your infrastructure permits. Elastic Layers require no unique infrastructure to be present for apps to be delivered at logon. All layers are self-describing and self-contained so all your environment needs is a connection to the file share. You don’t even have to connect to a database or management server for layers to get delivered!
And don’t forget the cloud. We’re the only solution that lets you use the same layers and operating system images that you build for on-premises VDI or XenApp in the Azure cloud. This package-once, deliver anywhere flexibility enables you to move between hypervisors and EUC platforms, and accelerates your move to the cloud.
With all the above factors combined, I truly believe that Citrix App Layering is the most robust solution on the market. Not just for Citrix environments either, as we continue to support the existing and future Microsoft RDS and VMWare View customers. You don’t have to take my word for it, go to Citrix Cloud and sign-in or create a new account to access a 60-day free trial.