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, the company wants the API to remain operational even if a single data center within an Azure region experiences an outage. The solution must provide automatic failover within the region. Which feature should be enabled for the App Service?
- AGeo-replication for App Service
- BDeployment slots for blue/green deployments
- CAuto-scaling rules based on CPU usage
- DZone redundancy for App Service Plan
Show answer & explanationAnswer & explanation
Correct answer: D. Zone redundancy for App Service Plan
Zone redundancy for an App Service Plan distributes instances across multiple Availability Zones within a single Azure region. This ensures that if one data center (Availability Zone) goes down, the application remains available on instances in other zones within the same region.
Why the other options are wrong
- A. Geo-replication would involve deploying to multiple Azure regions, providing regional disaster recovery, but the requirement is for high availability 'within an Azure region' against a 'single data center' outage.
- B. Deployment slots are for managing deployments (e.g., testing new versions) and do not inherently provide high availability against infrastructure failures.
- C. Auto-scaling improves performance and handles increased load but does not provide high availability against a data center outage.
Azure App Service Zone Redundancy
A feature for Azure App Service Plans that distributes app instances across multiple Availability Zones within a single Azure region, providing high availability against zonal (data center) failures.
- Requires Premium V2/V3 or Isolated V2 App Service Plan
- Distributes instances across 3 Availability Zones
- Provides resilience against single data center outages
- Operates within a single Azure region
Memory trick: Zones keep App Service alive, even if one building fails.