Microsoft Certified: Azure Solutions Architect ExpertDesign business continuity solutionsMedium

A manufacturing company uses an Azure App Service to host its critical order processing API. To ensure high availability and resilience against datacenter-level failures within a region, the company needs to deploy the App Service across multiple physical locations. The application is stateless. Which configuration should be used for the Azure App Service?

  1. AScale out the App Service Plan to multiple instances within a single Availability Set.
  2. BConfigure App Service Zone Redundancy for the App Service Plan.
  3. CDeploy the App Service Plan to a single Availability Zone.
  4. DDeploy multiple App Service Plans to different Azure regions and use Azure Front Door.
Show answer & explanation

Correct answer: B. Configure App Service Zone Redundancy for the App Service Plan.

App Service Zone Redundancy distributes App Service Plan instances across multiple Availability Zones within a region. This protects against datacenter-level failures by ensuring that if one zone goes down, instances in other zones can continue to serve traffic, meeting the high availability requirement within a region.

Why the other options are wrong

  • A. Availability Sets are for VMs, not directly for App Service Plans. Scaling out instances within a single zone does not protect against zone-wide failures.
  • C. Deploying to a single Availability Zone would make the application vulnerable to failures in that specific zone.
  • D. Deploying to multiple regions with Azure Front Door provides regional disaster recovery, which is a broader scope than the requirement for within-region datacenter failure resilience.

Azure App Service Zone Redundancy

Azure App Service Zone Redundancy distributes App Service Plan instances across multiple Availability Zones within a region to protect against datacenter-level failures.

  • Protects against datacenter-level failures within a region.
  • Requires a minimum of 3 instances in the App Service Plan.
  • Distributes instances across 3 Availability Zones.
  • Ensures high availability for stateless applications.

Memory trick: Zone Redundancy for App Service keeps your apps running through Zonal outages.

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