Merge pull request #299473 from anaharris-ms/azure-app-service-update-may-2025

[WIP] Reliability: App Service - Update for new AZ features

Author: v-regandowner

articles/app-service/environment/creation.md

@@ -3,7 +3,7 @@ title: Create an App Service Environment
 description: Learn how to create an App Service Environment.
 author: madsd
 ms.topic: article
-ms.date: 07/18/2024
+ms.date: 05/07/2025
 ms.author: madsd
 ---
 
@@ -33,9 +33,9 @@ With an *internal VIP*, an address in your App Service Environment subnet reache
 
 For the deployment type, you can choose *single zone*, *zone redundant*, or *host group*. The single zone is available in all regions where App Service Environment v3 is available. With the single zone deployment type, you have a minimum charge in your App Service plan of one instance of Windows Isolated v2. As soon as you use one or more instances, then that charge goes away. It isn't an additive charge.
 
-In a zone redundant App Service Environment, your apps spread across three zones in the same region. Zone redundant is available in regions that support availability zones. With this deployment type, the smallest size for your App Service plan is three instances. That ensures that there's an instance in each availability zone. App Service plans can be scaled up one or more instances at a time. Scaling doesn't need to be in units of three, but the app is only balanced across all availability zones when the total instances are multiples of three.
+In a zone redundant App Service Environment, your apps spread across the maximum number of zones available (up to three) in the same region. Zone redundant is available in regions that support availability zones. With this deployment type, the smallest size for your App Service plan is two instances. That ensures that there's an instance in at least two availability zones. App Service plans can be scaled up one or more instances at a time. Scaling doesn't need to be in units of two or three, but the app is only balanced across all availability zones when the total instances are multiples of two or three depending on the number of zones available. To view the number of available zones for the App Service Environment, see the *Maximum available zones* property in the **Configuration** blade in the Azure portal. If the value is two or three, the App Service Environment is zone redundant.
 
-A zone redundant deployment has triple the infrastructure, and ensures that even if two of the three zones go down, your workloads remain available. Due to the increased system need, the minimum charge for a zone redundant App Service Environment is 18 cores. If you've fewer than this number of cores across all App Service plans in your App Service Environment, the difference is charged as Windows I1v2. If you've 18 or more cores, there's no added charge to have a zone redundant App Service Environment. To learn more about zone redundancy, see [Regions and availability zones](./overview-zone-redundancy.md). For sample calculations for zone redundant App Service Environment, see [App Service Environment pricing](overview.md#pricing).
+A zone redundant deployment has quadruple or triple the infrastructure depending on the maximum available zone count, and ensures that even if a zone goes down, your workloads remain available. There's no added charge to have a zone redundant App Service Environment. To learn more about zone redundancy, see [Regions and availability zones](../../reliability/reliability-app-service.md?pivots=isolated).
 
 In a host group deployment, your apps are deployed onto a dedicated host group. The dedicated host group isn't zone redundant. With this type of deployment, you can install and use your App Service Environment on dedicated hardware. There's no minimum instance charge for using App Service Environment on a dedicated host group, but you do have to pay for the host group when you're provisioning the App Service Environment. You also pay a discounted App Service plan rate as you create your plans and scale out.
 

articles/app-service/environment/overview.md

@@ -66,7 +66,7 @@ A benefit of using an App Service Environment instead of a multitenant service i
 App Service Environment v3 differs from earlier versions in the following ways:
 
 - There are no networking dependencies on the customer's virtual network. You can secure all inbound and outbound traffic and route outbound traffic as you want.
-- You can deploy an App Service Environment v3 that's enabled for zone redundancy. You set zone redundancy only during creation and only in regions where all App Service Environment v3 dependencies are zone redundant. Zone redundancy is a deployment time only decision. Changing zone redundancy isn't possible after it has been deployed. With zone redundant App Service Environment, each App Service Plan on the App Service Environment needs to have a minimum of three instances so that they can be spread across zones. For more information, see [Migrate App Service Environment to availability zone support](../../reliability/migrate-app-service-environment.md).
+- You can deploy an App Service Environment v3 that's enabled for zone redundancy. You set zone redundancy only in regions where all App Service Environment v3 dependencies are zone redundant. Zone redundancy can be enabled at creation time, or any time after the deployment is complete. With zone redundant App Service Environment, each App Service Plan on the App Service Environment needs to have a minimum of two instances so that they can be spread across zones. Each App Service plan's zone redundancy status is independent. This means that you can have a mix of zone redundant and non-zone redundant plans. To make the plans zone redundant, the App Service Environment must have zone redundancy enabled. The non-zone redundant plans can be scaled down to a single instance. For more information, see [Reliability in Azure App Service](../../reliability/reliability-app-service.md?pivots=isolated).
 - You can deploy an App Service Environment v3 on a dedicated host group. Host group deployments aren't zone redundant.
 - Scaling is faster than with an App Service Environment v2. Although scaling still isn't immediate, as in the multitenant service, it's a lot faster.
 - Front-end scaling adjustments are no longer required. App Service Environment v3 front ends automatically scale to meet your needs and are deployed on better hosts.
@@ -83,36 +83,9 @@ A few features that were available in earlier versions of App Service Environmen
 With App Service Environment v3, the pricing model varies depending on the type of App Service Environment deployment you have. The three pricing models are:
 
 - **App Service Environment v3**: If the App Service Environment is empty, there's a charge as though you have one instance of Windows I1v2. The one instance charge isn't an additive charge but is applied only if the App Service Environment is empty.
-- **Zone redundant App Service Environment v3**: There's a minimum charge of 18 cores. There's no added charge for availability zone support if you have 18 or more cores across your App Service plan instances. If you have fewer than 18 cores across your App Service plans in the zone redundant App Service Environment, the difference between 18 cores and the sum of the cores from the running instance count is charged as additional Windows I1v2 instances.
+- **Zone redundant App Service Environment v3**: There's no added charge for availability zone support. The pricing model is the same as a non-zone redundant App Service Environment.
 - **Dedicated host App Service Environment v3**: With a dedicated host deployment, you're charged for two dedicated hosts per our pricing when you create the App Service Environment v3 and then, as you scale, you're charged a specialized Isolated v2 rate per vCore. I1v2 uses two vCores, I2v2 uses four vCores, and I3v2 uses eight vCores per instance.
 
-> [!NOTE]
-> Sample calculations for zone redundant App Service Environment v3 pricing:
->
-> 1. Your zone redundant App Service Environment v3 has 3 Linux I1v2 instances in a single App Service plan.  
->
-> - An I1v2 instance has 2 cores.  
-> - In total, across your instances, you have 6 cores.  
-> - 18 cores - 6 cores = 12 cores  
-> - 12 cores is equivalent to 6 I1v2 instances.  
-> - You'll be charged for your 3 Linux I1v2 instances plus 6 additional Windows I1v2 instances.  
->
-> 2. Your zone redundant App Service Environment v3 has 3 Linux I2v2 instances in a single App Service plan.  
->
-> - An I2v2 instance has 4 cores.  
-> - In total, across your instances, you have 12 cores.  
-> - 18 cores - 12 cores = 6 cores  
-> - 6 cores is equivalent to 3 I1v2 instances.  
-> - You'll be charged for your 3 Linux I2v2 instances plus 3 additional Windows I1v2 instances.  
->
-> 3. Your zone redundant App Service Environment v3 has 4 Linux I3v2 instances in a single App Service plan.  
->
-> - An I3v2 instance has 8 cores.  
-> - In total, across your instances, you have 32 cores.  
-> - 32 cores is greater than 18 cores  
-> - You won't be charged for any additional cores.  
->
-
 Reserved Instance pricing for Isolated v2 is available and is described in [How reservation discounts apply to Azure App Service](../../cost-management-billing/reservations/reservation-discount-app-service.md). The pricing, along with Reserved Instance pricing, is available at [App Service pricing](https://azure.microsoft.com/pricing/details/app-service/windows/) under the Isolated v2 plan.
 
 ## Regions