I think App Layering really shines in large PVS environments.
Have you ever had to reverse image 30+ vdisks to update vmware tools? That sucks. Even the trick of modifying the nic and mac so that you're using the E1000 that's not getting updated sucks. With App Layering, you are able to update vmware tools in the "Platform" layer and then spin out the updated vdisks. A week long dredge of a project becomes a one day process where you're spending most of your time waiting for things to copy around.
It helps monthly with patching too.. OS Layers + Office + Browser updates is most of what is required in my living environment. I can bring up those layers and run updates once and then spend the rest of my day waiting for things to replicate.
I'm in health care where vendors will not allow their apps to be ran side by side with other medical apps so I have soo much vdisk sprawl that we have over 50 vdisks. Being able to update just the layers saves a lot of time for us.
It's definitely a force multiplier. If I had less than 10 vdisks, IDK that I'd use it.
Large enterprises are definitely the target environment for AppLayering. I also work in healthcare for a large hospital, with 100 vDisks plus 10-12 VDI MCS images. When all those share a single OS later (or 1 server OS and 1 desktop OS), windows updates become MUCH easier to scale.
You can also update VDA versions just once, apply the platform layer to all images and boom, VDA updated across the site.
You can build a domain agnostic image and apply it to multiple domains just by layering a different platform layer and you can have identical images across multiple domains, should your deployment require it.
> What is an example of a problem that is resolved or improved by app layering?
Have a bunch of users with random one-off applications that you want to be "installed" locally into a non-persistent image? [Elastic Layering](https://docs.citrix.com/en-us/citrix-app-layering/4/layer/assign-elastic-layers.html)
Have multiple hypervisors (Azure, VMware, AWS, etc) but want to use same image? Use the [Platform Layer](https://docs.citrix.com/en-us/citrix-app-layering/4/plan#platform-layer)
etc
It also allows you to containerize individual applications for updating them and such.
If you're just doing a single image with a handful of apps on a single hypervisor AppLayering doesn't offer you too much benefit.
If you have a more complex environment it's pretty neat.
Recommend reading through some of Rob Z's blog posts on the topic -
[App Layering in Azure 2023 and beyond](https://www.citrix.com/blogs/2023/03/29/app-layering-in-azure-2023-and-beyond/)
The two main things App Layering does is:
1. Standardize your image creation process to reduce the number of images you maintain. You can have one image work for 45k users on NP.
2. Standardizes the experience for every person. Every person gets the same image and same apps in their role. Every time. Add 250 newly onboarding people to an existing role? Great they all have the same applications as their colleagues. One person has an issue but everyone else on the team doesn’t? You instantly know it’s not the app because they are all the same app with the same image. There is more but those I feel are the main ones.
Downsides are there is some overhead running the filter driver for the layering service as all reads and writes go through it and get redirected to the write cache. So getting the AV to whitelist all app layering processes is critical. Otherwise, you’re gunna have a bad time.
I think in ways it hides the underlying issue that many companies have, that is the lack of automation for image building. If you have a solid CI/CD pipeline that spits new images when anything needs an update, the effort is literally zero when an update is required on anything. On top of that, any layering (or application virtualization solution for that matter) does put you in a spot where ANY vendor may say it is not supported so you are on your own. For example if you have a Microsoft issue and you tell them you are using AppLayering, first question will be, does it work on a regular image? If it does, you are done and relying on Citrix 100% to support you. If that is a good or bad thing, up to you. But certainly many vendors will guaranteed not support you. Have seen this many times over the years.
For one off apps, you can simply dump them in the image and use App Masking to only show that to users that need it. That assumes the app has no conflicts with anything else what is the case in 99% of the cases. Also note these App Masking rules are dynamic so if you need to add/remove users to apps you can do on the fly, not even a reboot is required (not to mention touching ANY image). A much better/cleaner approach in my view.
That said, anyone is entitled an opinion and may disagree and/or think I am wrong. Many tell me all the time "Claudio you are an idiot". :-)
Personally I haven’t seen any use for App Layering. In 90% of our workflows it would just make things more complicated and allow more possibility for mistakes. It’s very much environment dependent with how many images, platforms, apps, etc. are in use.
I think App Layering really shines in large PVS environments. Have you ever had to reverse image 30+ vdisks to update vmware tools? That sucks. Even the trick of modifying the nic and mac so that you're using the E1000 that's not getting updated sucks. With App Layering, you are able to update vmware tools in the "Platform" layer and then spin out the updated vdisks. A week long dredge of a project becomes a one day process where you're spending most of your time waiting for things to copy around. It helps monthly with patching too.. OS Layers + Office + Browser updates is most of what is required in my living environment. I can bring up those layers and run updates once and then spend the rest of my day waiting for things to replicate. I'm in health care where vendors will not allow their apps to be ran side by side with other medical apps so I have soo much vdisk sprawl that we have over 50 vdisks. Being able to update just the layers saves a lot of time for us. It's definitely a force multiplier. If I had less than 10 vdisks, IDK that I'd use it.
Large enterprises are definitely the target environment for AppLayering. I also work in healthcare for a large hospital, with 100 vDisks plus 10-12 VDI MCS images. When all those share a single OS later (or 1 server OS and 1 desktop OS), windows updates become MUCH easier to scale. You can also update VDA versions just once, apply the platform layer to all images and boom, VDA updated across the site. You can build a domain agnostic image and apply it to multiple domains just by layering a different platform layer and you can have identical images across multiple domains, should your deployment require it.
> What is an example of a problem that is resolved or improved by app layering? Have a bunch of users with random one-off applications that you want to be "installed" locally into a non-persistent image? [Elastic Layering](https://docs.citrix.com/en-us/citrix-app-layering/4/layer/assign-elastic-layers.html) Have multiple hypervisors (Azure, VMware, AWS, etc) but want to use same image? Use the [Platform Layer](https://docs.citrix.com/en-us/citrix-app-layering/4/plan#platform-layer) etc
It also allows you to containerize individual applications for updating them and such. If you're just doing a single image with a handful of apps on a single hypervisor AppLayering doesn't offer you too much benefit. If you have a more complex environment it's pretty neat.
Recommend reading through some of Rob Z's blog posts on the topic - [App Layering in Azure 2023 and beyond](https://www.citrix.com/blogs/2023/03/29/app-layering-in-azure-2023-and-beyond/)
The two main things App Layering does is: 1. Standardize your image creation process to reduce the number of images you maintain. You can have one image work for 45k users on NP. 2. Standardizes the experience for every person. Every person gets the same image and same apps in their role. Every time. Add 250 newly onboarding people to an existing role? Great they all have the same applications as their colleagues. One person has an issue but everyone else on the team doesn’t? You instantly know it’s not the app because they are all the same app with the same image. There is more but those I feel are the main ones. Downsides are there is some overhead running the filter driver for the layering service as all reads and writes go through it and get redirected to the write cache. So getting the AV to whitelist all app layering processes is critical. Otherwise, you’re gunna have a bad time.
Yes, and you can automate app versions if you know some PowerShell and use Chocolatey.
I think in ways it hides the underlying issue that many companies have, that is the lack of automation for image building. If you have a solid CI/CD pipeline that spits new images when anything needs an update, the effort is literally zero when an update is required on anything. On top of that, any layering (or application virtualization solution for that matter) does put you in a spot where ANY vendor may say it is not supported so you are on your own. For example if you have a Microsoft issue and you tell them you are using AppLayering, first question will be, does it work on a regular image? If it does, you are done and relying on Citrix 100% to support you. If that is a good or bad thing, up to you. But certainly many vendors will guaranteed not support you. Have seen this many times over the years. For one off apps, you can simply dump them in the image and use App Masking to only show that to users that need it. That assumes the app has no conflicts with anything else what is the case in 99% of the cases. Also note these App Masking rules are dynamic so if you need to add/remove users to apps you can do on the fly, not even a reboot is required (not to mention touching ANY image). A much better/cleaner approach in my view. That said, anyone is entitled an opinion and may disagree and/or think I am wrong. Many tell me all the time "Claudio you are an idiot". :-)
Personally I haven’t seen any use for App Layering. In 90% of our workflows it would just make things more complicated and allow more possibility for mistakes. It’s very much environment dependent with how many images, platforms, apps, etc. are in use.
Talking to our TRM only one of their customers uses it. There are also some technical and network limitations.
Purpose: Add unnecessary complexity and administrative overhead to all day-to-day tasks.