azure-reliability/references/zone-redundancy-checks.md

Zone Redundancy — Platform Overview

Overview

Zone redundancy distributes compute instances across availability zones within a region. If one zone fails, instances in other zones continue serving traffic automatically.

This file covers platform-level discovery and concepts. For service-specific assessment queries, configuration commands, and IaC patches, see:

Service	Reference
Azure App Service	services/app-service/reliability.md
Azure Functions	services/functions/reliability.md

Azure Container Apps deep-dive references are planned for a future version of this skill. The discovery query below still surfaces those resources — just don't dispatch to a per-service reference for them yet.

Discovery: Find All Non-Zone-Redundant Compute

⚠️ Output format: Use --query "data[]" -o json for az graph query. -o table only renders summary columns (Count, Total_records) and hides projected fields. Pipe JSON through jq if you need a table view.

Use this single query to discover every compute resource in scope that is not zone-redundant. Use it during Phase 1 (Discover Resources) to decide which service references to load.

az graph query -q "
Resources
| where type in~ ('microsoft.web/serverfarms', 'microsoft.app/managedenvironments')
| extend zoneRedundant = tobool(properties.zoneRedundant)
| where zoneRedundant == false or isnull(zoneRedundant)
| project name, type, resourceGroup, location, sku=sku.name
| order by type asc
" --query "data[]" -o json

For each row in the result, dispatch to the matching service reference:

• microsoft.web/serverfarms with kind contains 'functionapp' → Functions reference
• microsoft.web/serverfarms (other kinds) → App Service reference
• microsoft.app/managedenvironments → planned (Container Apps) — surface in the discovery summary, do not deep-dive

Regions Supporting Availability Zones

az functionapp list-flexconsumption-locations --zone-redundant=true

Common regions with AZ support across Functions, App Service, and Container Apps:

• East US, East US 2, West US 2, West US 3
• Central US, South Central US
• North Europe, West Europe, UK South
• France Central, Germany West Central, Sweden Central
• Southeast Asia, Japan East, Australia East

Service-specific region availability differs. Always confirm support for the specific SKU/plan in the target region using the per-service reference.

Reporting

For the assessment table's Zone redundancy — compute row, the per-service references define exactly what 🟢 ON / 🟡 PARTIAL / 🔴 OFF mean for that service (e.g. ZR + minimum instance count for App Service, Premium Functions). Only App Service and Functions have a per-service reference in this skill version; Container Apps support is planned.