Azure Documentation

Azure Private Link Best Practices

This document outlines recommended practices for implementing and managing Azure Private Link, ensuring secure, reliable, and efficient private connectivity to Azure services.

Key Takeaway: Azure Private Link offers a robust way to access Azure PaaS services and customer-owned services privately. Adhering to best practices is crucial for security, performance, and cost optimization.

1. Network Design and Planning

Thorough planning is essential before deploying Private Link. Consider the following:

  • Network Segmentation: Design your virtual networks (VNets) with appropriate subnetting to logically separate resources and control traffic flow.
  • IP Address Management: Ensure sufficient IP address space is allocated to subnets where Private Endpoints will reside. Avoid IP conflicts.
  • DNS Resolution: Proper DNS configuration is critical. You must configure DNS to resolve the private endpoint IP address for the service. Azure provides Private DNS Zones for this purpose.
  • Traffic Flow: Understand the intended traffic flow from your clients to the private-linked service. This helps in designing firewall rules and network security groups (NSGs).

2. Private Endpoint Configuration

2.1. Naming Conventions

Adopt a consistent and descriptive naming convention for your Private Endpoints. This improves manageability and clarity.

Example: pe- [resource-type]- [service-name]- [region]

2.2. Network Security Groups (NSGs)

Apply NSGs to the subnet where your Private Endpoint resides. This allows you to control inbound and outbound traffic to the Private Endpoint itself.

Best Practice: Only allow necessary traffic. For most Private Link scenarios, you'll primarily need to allow outbound traffic from your client subnets to the Private Endpoint's VNet.

2.3. Private DNS Zones

Leverage Azure Private DNS Zones for seamless DNS resolution. Link the Private DNS Zone to your VNet where the Private Endpoint is deployed.

Example: For Azure Storage, you would create a Private DNS Zone for privatelink.blob.core.windows.net and link it to your VNet. Then, create an A record pointing the service FQDN to the Private Endpoint's IP address.

# Example DNS record for Azure Storage
Host name:     mystorageaccount.privatelink.blob.core.windows.net.
Record type:   A
IP Address:    10.0.0.4

3. Service Considerations

3.1. Supported Services

Familiarize yourself with the list of Azure services that support Private Link. This ensures you are using the right service for your private connectivity needs.

3.2. Service-Specific Configurations

Some services may have additional configurations or prerequisites for Private Link integration. Always refer to the specific service documentation.

4. Security and Access Control

4.1. Resource Provider Permissions

Ensure the identity (user, service principal, or managed identity) creating the Private Endpoint has the necessary permissions on the target service resource (e.g., "Microsoft.Network/privateEndpoints/write" and "Microsoft.Network/privateLinkServices/consumer/write").

4.2. Approval Workflow

For services where the resource owner has enabled approval, understand the approval process for incoming Private Link requests. This ensures only authorized connections are established.

4.3. Network Firewalls

If you are using Azure Firewall or another network virtual appliance (NVA) for outbound filtering, ensure that you allow traffic to the Private Endpoint IP address or the service's FQDN (if using public endpoints in conjunction with private endpoints, though this is often discouraged for pure private access).

5. Monitoring and Management

5.1. Azure Monitor Integration

Utilize Azure Monitor to track the health, performance, and connection status of your Private Endpoints and Private Link Services.

Key metrics include:

  • Data In/Out
  • Connection status
  • Latency

5.2. Auditing

Enable diagnostic logs for Private Link services and Private Endpoints to audit access and configuration changes.

6. Cost Management

Be aware of the pricing for Private Link, which includes costs for Private Endpoints and data processed.

Tip: Optimize your network design and service usage to manage costs effectively.

Important: While Private Link is generally more secure and often preferred over public endpoints, ensure your application logic and security controls are still robust. Private Link secures the network path, not necessarily the application itself.