Azure Private Link Documentation

Azure Private Link

Azure Private Link provides the core Azure platform capabilities to privately connect to Azure SaaS services, Azure-hosted Platform as a Service (PaaS), and Azure Virtual Network (VNet) customer-owned services. Traffic between your Azure Virtual Network and the service travels the Microsoft backbone network, eliminating exposure to the public internet.

What is Azure Private Link?

Azure Private Link allows you to create a private endpoint in your virtual network. This private endpoint maps to a specific service instance in Azure. When you access that service through the private endpoint, your traffic stays within your virtual network and then traverses the Microsoft backbone network directly to the service. This ensures that your data does not traverse the public internet.

Key components include:

Private Endpoint: A network interface that connects privately and securely to a service.
Private Link Service: A service that enables you to expose your own services (hosted in Azure) to consumers securely.
Service Consumer: The virtual network that uses a private endpoint to access a service.
Service Provider: The Azure service (e.g., Azure Storage, Azure SQL Database) or your own hosted service that is made accessible via Private Link.

Benefits of Azure Private Link

Enhanced Security: Eliminates public internet exposure for your critical services.
Simplified Network Architecture: Reduces the need for complex VNet peering or VPN configurations for accessing Azure services.
Compliance: Helps meet regulatory and compliance requirements for data privacy and security.
Consistent Networking Experience: Provides a uniform way to access both Azure PaaS/SaaS services and your own services.
Private IP Address Access: Services are accessible via private IP addresses within your virtual network.

Core Concepts

Understanding these concepts is crucial:

Private Endpoint

A network interface in your virtual network that is assigned a private IP address from your network. It connects to a specific service instance. For Azure services, the service provider creates a service alias or resource ID that you use to create the private endpoint.

Network Security Groups (NSGs)

NSGs can be associated with the subnet containing the private endpoint to control inbound and outbound traffic. However, you cannot use NSGs to block traffic to the Private Link service itself, as the traffic is routed via the Microsoft backbone.

Private DNS Zone

For Azure services, Private Link often requires the use of a Private DNS Zone to map the service's FQDN (Fully Qualified Domain Name) to the private IP address of the private endpoint. This ensures that when your applications try to resolve the service's hostname, they get the private IP.

                        Example: If you create a private endpoint for an Azure Storage account, you'll need to configure a Private DNS Zone (e.g., privatelink.blob.core.windows.net) to resolve the storage account's hostname to its private IP.
                    

Private Link Service

This allows you to expose your own applications and services running in Azure (e.g., on a VM scale set or AKS) to other Azure customers or to different VNets within your organization. Consumers access your service via a private endpoint in their virtual network.

Common Use Cases

Securely accessing Azure PaaS services like Azure SQL Database, Azure Storage, Azure Key Vault, Azure Cosmos DB, etc.
Connecting on-premises applications to Azure services without exposing them to the internet.
Enabling secure communication between different VNets within an organization for accessing shared services.
Providing secure access to custom applications hosted within Azure.

Getting Started with Azure Private Link

Here's a general workflow:

Identify the Service: Determine which Azure service you want to connect to privately.
Check Service Availability: Ensure the Azure service supports Private Link. Most major Azure services do.
Create a Private Endpoint:
- Navigate to the Private Endpoint blade in the Azure portal.
- Select your subscription, resource group, region.
- Choose the target service and the specific service instance.
- Select the virtual network and subnet where you want to create the private endpoint.
- Configure Private DNS integration (recommended).
- Review and create the private endpoint.
Configure DNS: If you didn't use automatic DNS integration, manually create or update your DNS records (e.g., in a Private DNS Zone) to point the service's FQDN to the private IP address of the private endpoint.
Test Connectivity: From a resource within your virtual network (e.g., a VM), attempt to connect to the service using its standard FQDN. The connection should now be routed via the private endpoint.

Note: For some services, the service provider needs to approve the private endpoint connection before it becomes active.

Pricing

Azure Private Link pricing has two main components:

Private Endpoint Connection: Charged per hour for each private endpoint connection.
Data Processed: Charged per GB of data processed through the private endpoint.

For detailed pricing information, please refer to the Azure Private Link Pricing page.