Azure Private Link Documentation

Azure Private Link Best Practices

Azure Private Link enables you to access Azure Platform as a Service (PaaS) and Azure hosted customer-owned services securely and privately from within your virtual network. This document outlines best practices for deploying and managing Private Link services.

1. Network Design and Planning

  • Resource Scope: Understand the scope of your Private Link service. Is it for a single virtual network, multiple VNets, or on-premises connectivity via VPN/ExpressRoute?
  • DNS Resolution: Plan your DNS strategy. Private Link requires specific DNS record configurations to ensure proper name resolution for your private endpoints. Azure Private DNS Zones are highly recommended.
  • IP Address Management: Allocate sufficient IP address space in your virtual networks for private endpoints. Avoid IP address conflicts.
  • Network Security Groups (NSGs): While Private Link encrypts traffic between your VNet and the service, NSGs can still be used to control traffic flow to and from the subnet where the private endpoint resides.

2. Security Considerations

  • Least Privilege Access: Grant only necessary permissions to users and applications accessing the service via Private Link.
  • Service Access Control: Configure the service provider's access control lists (ACLs) to restrict which virtual networks or specific private endpoints can connect to your service.
  • Monitoring and Auditing: Enable diagnostic logging for your Private Link services and private endpoints. Monitor connection status, traffic patterns, and potential security events. Use Azure Monitor and Log Analytics.
  • VNet Peering vs. Private Link: Understand when to use VNet peering and when Private Link is more appropriate. Private Link offers a more isolated and secure connection to Azure PaaS services compared to exposing them over the public internet or through VNet peering.

3. Deployment and Management

  • Automate Deployments: Use Infrastructure as Code (IaC) tools like Azure Resource Manager (ARM) templates, Bicep, or Terraform to automate the deployment and management of private endpoints and associated DNS configurations.
  • Naming Conventions: Establish clear and consistent naming conventions for private endpoints, DNS zones, and related resources for easier management and identification.
  • Tagging: Apply appropriate tags to your private endpoints and related resources to facilitate organization, cost management, and access control.
  • Service Endpoints vs. Private Endpoints: Understand the differences. Service Endpoints allow access to Azure services from your VNet over a managed identity, while Private Endpoints provide a private IP address within your VNet for the service. Choose the best option based on your security and network requirements.

4. DNS Configuration

Proper DNS resolution is critical for Private Link to function correctly. Here are key considerations:

  • Azure Private DNS Zones: Integrate your private endpoints with Azure Private DNS Zones. This allows for automatic record creation and simplifies DNS management.
  • Custom DNS Servers: If you use custom DNS servers (on-premises or within Azure), ensure they are configured to forward DNS queries for Azure services to the appropriate Azure DNS resolvers or to Azure Private DNS Zones.
  • Record Updates: Be aware that Private Link might create or update DNS records. Plan for these changes and ensure your DNS infrastructure can handle them.
  • Alias Records: For some services, alias records might be used. Understand their behavior.

5. Performance and Scalability

  • Bandwidth Considerations: Private Link does not introduce additional latency beyond network path. Ensure your VNet's outbound bandwidth is sufficient for the services accessed via Private Link.
  • Service Limits: Be aware of any service-specific limits or quotas related to Private Link connections.
  • Endpoint Placement: Deploy private endpoints in subnets that are well-connected to the resources that will consume the service.

By adhering to these best practices, you can ensure a secure, reliable, and efficient Private Link deployment within your Azure environment.