Azure Front Door Structure Analysis

A PowerShell script to analyze Classic Azure Front Door (AFD) resources and assess migration readiness to Standard or Premium tiers.

Overview

This script parses JSON exports of Classic Azure Front Door resources and provides:

• Detailed inventory of backend pools, backends, custom domains, and routing rules
• Mapping to equivalent Premium/Standard Front Door constructs
• Complete limit analysis for both Standard and Premium tiers
• Clear warnings about migration blockers
• Actionable recommendations for resources exceeding limits

Features

✅ Complete Limit Checking

• All Standard tier limits (Custom Domains, Origin Groups, Origins, Routes, Rule Sets)
• All Premium tier limits
• Per-pool origin limits (50 origins per group)
• Per-ruleset limits (100 rules per set)

✅ Clear Output

• Color-coded warnings (Green = OK, Yellow = Warning, Red = Critical)
• Migration verdict with specific action items
• Detailed resource breakdown

✅ Simple & Maintainable

• Direct JSON property access (no complex recursion)
• Clean, linear logic flow
• Easy to extend for additional checks

Requirements

• PowerShell 5.1 or later
• Azure Front Door resource exported to JSON

Usage

1. Export Your Classic Front Door to JSON

Using Azure CLI:

az network front-door show --name <your-frontdoor-name> --resource-group <your-rg> > frontdoor-export.json

Using Azure PowerShell:

Get-AzFrontDoor -Name <your-frontdoor-name> -ResourceGroupName <your-rg> | ConvertTo-Json -Depth 10 | Out-File frontdoor-export.json

2. Run the Analysis Script

.\get-afdstructure.ps1 -JsonFile ".\frontdoor-export.json"

Example Output

=== Backend Pools and Backends ===

Pool: production-pool-01          Backends: 10
    - 10.0.1.10
    - 10.0.1.11
    ...

=== Custom Domains (FrontendEndpoints) ===

Name: www-example-com             Hostname: www.example.com
Name: api-example-com             Hostname: api.example.com

====================================
Classic Front Door - Resource Summary
====================================
Total FrontendEndpoints  : 40
Total Backend Pools      : 98
Total Backends           : 342
Total RoutingRules       : 54
Total RulesEngines       : 21

====================================
Premium/Standard Front Door - Equivalent Resources
====================================
Custom Domains (from FrontendEndpoints)      : 40
Origin Groups (from Backend Pools)           : 98
Origins (from Backends)                      : 342
Routes (from RoutingRules)                   : 54
Rule Sets (from RulesEngines)                : 21

====================================
Migration Limit Analysis
====================================

Standard Tier:
--------------
  ❌ Origins: 342 exceeds limit of 100

Premium Tier:
-------------
  ❌ Origins: 342 exceeds limit of 200

====================================
⚠️  Migration Issues Detected
Review the warnings above before proceeding with migration.
====================================

Azure Front Door Limits

Standard Tier

• Custom Domains: 100
• Origin Groups: 100
• Origins per Profile: 100
• Routes: 100
• Rule Sets: 100

Premium Tier

• Custom Domains: 500
• Origin Groups: 200
• Origins per Profile: 200
• Routes: 200
• Rule Sets: 200

Common (Both Tiers)

• Origins per Group: 50
• Rules per Rule Set: 100

Resource Mapping

Classic Front Door	Standard/Premium Front Door
Frontend Endpoint	Custom Domain
Backend Pool	Origin Group
Backend	Origin
Routing Rule	Route
Rules Engine	Rule Set

Files

• get-afdstructure.ps1 - Main analysis script
• .gitignore - Git configuration
• Tests/ - Folder for test JSON files (not tracked by Git)

Testing

Place your Front Door JSON exports in the Tests/ folder:

.\get-afdstructure.ps1 -JsonFile ".\Tests\your-frontdoor.json"

Migration Guidance

✅ No Warnings

Your Classic Front Door can be migrated to both Standard and Premium tiers without changes.

⚠️ Tier Limit Violations

If resources exceed Standard limits but fit within Premium limits, migrate to Premium tier.

🔴 Per-Resource Violations

• Pool with >50 origins: Split into multiple origin groups before migration
• Rule Engine with >100 rules: Split into multiple rule sets before migration

🔴 Both Tiers Exceeded

Requires architecture redesign before migration. Consider:

• Consolidating duplicate origins
• Splitting into multiple Front Door profiles
• Reviewing if all resources are actively used

Contributing

Improvements and bug reports are welcome! Please ensure:

• All limit checks remain functional
• Output remains clear and actionable
• Code stays simple and maintainable

License

This script is provided as-is for Azure Front Door migration assessment purposes.

References

• Azure Front Door Service Limits
• Migrate from Classic to Standard/Premium
• Classic vs Standard/Premium Comparison