Azure PostgreSQL Private Endpoint Approval Failure in Cross-Subscription Setups

Organizations implementing Azure Database for PostgreSQL Flexible Server across multiple subscriptions or tenants encounter persistent Private Endpoint approval failures – a configuration hurdle causing significant deployment delays. These failures manifest as perpetually pending connections, silent approval reversals, and misleading "No Access" errors despite correct RBAC permissions. The core issue stems from Azure's backend authorization requirements during Private Link establishment, demanding specific subscription-level configurations often overlooked in multi-subscription architectures.

Authorization Failure Mechanics

When approving Private Endpoints for PostgreSQL Flexible Server, Azure performs dual operations:

1. Service Provider Side: PostgreSQL resource approval initiation
2. Consumer Side: Private Link Service Proxy update on the Private Endpoint resource

The critical failure point occurs during step 2 when the Private Endpoint resides in a separate subscription or tenant. Azure requires:

• Registered Resource Providers: Both Microsoft.Network and Microsoft.DBforPostgreSQL must be activated in both subscriptions (Resource Provider documentation)
• Network Write Permissions: Approving identities need Microsoft.Network/privateEndpoints/privateLinkServiceProxies/write rights on the Private Endpoint scope

Without these, authorization errors like AuthorizationFailed: The client '<object-id>' does not have authorization... appear despite correct PostgreSQL permissions. This differs from services like Azure Key Vault, which have simpler approval workflows.

Resolution Protocol

Step	Action	Verification Method
1	Register Microsoft.Network & Microsoft.DBforPostgreSQL in both subscriptions	Azure Portal > Subscriptions > Resource providers
2	Assign Network Contributor role to approver identity on Private Endpoint scope	Access Control (IAM) blade
3	Refresh authentication tokens	Sign out/in of Azure Portal/Azure CLI

Post-correction, Private Endpoints transition from Pending to Approved within minutes without retry errors.

Strategic Prevention Framework

1. Landing Zone Pre-Registration: Automate provider registration via Azure Policy or Terraform in management groups
2. Cross-Subscription Readiness Checklist:
   • Validate provider registrations
   • Verify network permissions matrix
   • Test approval workflow before production deployment
3. Service-Specific Documentation: Note PostgreSQL's dual-operation requirement differs from other Azure services (Private Endpoint comparisons)

Business Impact Analysis

Unresolved approval failures cause:

• 48+ hour troubleshooting cycles for network/DB teams
• Project delays during critical migration phases
• Resource dependency deadlocks in CI/CD pipelines

Financial implications include wasted engineering hours and delayed application deployments. A financial services client reduced Private Endpoint deployment time from 72 hours to 15 minutes after implementing provider registration automation.

Architectural Recommendations

• Treat subscription resource providers as foundational infrastructure
• Implement cross-subscription permission audits during tenant onboarding
• Use service principals with predefined roles for approval workflows
• Monitor Private Endpoint state transitions via Azure Monitor alerts

Proactive configuration prevents opaque authorization errors that traditionally require Microsoft Support intervention. Enterprises managing complex Azure environments should prioritize these checks before implementing Private Link for PostgreSQL or other database services across subscription boundaries.

References:

• Manage Azure Private Endpoints
• PostgreSQL Approval Documentation
• Private Link Service Design Patterns