Configuring CNAME records for private endpoints in Azure

Question

Pulumi · Accepted Answer

To configure CNAME records for private endpoints in Azure using Pulumi, you'll need to understand the various components and services involved and how they interact with each other. The primary resources you'll work with are the Azure DNS Zone, DNS Record Sets, and Azure Private Endpoints.

First, let's go over the key resources:

- **Azure DNS Zone**: This is where you will configure your domain's DNS settings.
- **DNS Record Sets**: Within your DNS Zone, you will create DNS record sets, which in this case will be CNAME records that will point to your private endpoints.
- **Azure Private Endpoint**: A private endpoint is a network interface that connects you privately and securely to Azure services powered by Azure Private Link.

Here's the general process:

1. You create a private endpoint for the Azure service you want to access privately.
2. You obtain the private endpoint's information, such as its private IP address or a data plane FQDN (Fully Qualified Domain Name).
3. You configure a CNAME record in your Azure DNS Zone to point to the private endpoint’s FQDN.

Now, let’s write a program in TypeScript that configures a CNAME record pointing to an Azure Private Endpoint. We'll be using the `azure-native` package, as it provides direct access to Azure resources.

Please remember that the following code assumes that you have pre-existing Azure infrastructure like a DNS Zone and that you are logged into Azure and have selected the right subscription.

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as azure_native from "@pulumi/azure-native";

// You would replace these variables with the actual IDs or names of your resources.
const dnsZoneName = "example.com"; // Your DNS Zone Name
const privateEndpointName = "myPrivateEndpoint"; // Your Private Endpoint Name
const resourceGroupName = "resource-group-name"; // Your Resource Group Name

// Resource group (Assuming it already exists in your Azure subscription)
const resourceGroup = azure_native.resources.getResourceGroup({
    resourceGroupName: resourceGroupName,
});

// Retrieve an existing DNS zone
const dnsZone = azure_native.network.getZones({
    resourceGroupName: resourceGroupName,
    zoneName: dnsZoneName,
});

// Retrieve an existing Private Endpoint
const privateEndpoint = azure_native.network.getPrivateEndpoint({
    resourceGroupName: resourceGroupName,
    privateEndpointName: privateEndpointName,
});

// Now, let's configure the CNAME record in your DNS Zone to point to the Private Endpoint
const cnameRecordSet = new azure_native.network.RecordSet("cnameRecordSet", {
    resourceGroupName: resourceGroupName,
    zoneName: dnsZoneName,
    relativeRecordSetName: "myapp", // The subdomain portion of your FQDN (e.g., "myapp" in "myapp.example.com")
    recordType: "CNAME",
    ttl: 300, // Time-to-live in seconds
    cnameRecord: {
        cname: privateEndpoint.apply(ep => ep.customDnsConfigs[0].fqdn), // Assuming the FQDN is part of the customDnsConfigs of the Private Endpoint
    },
}, { dependsOn: [dnsZone] });

// To retrieve the CNAME record for output after deployment
export const cname = cnameRecordSet.cnameRecord.apply(cnameRecord => cnameRecord.cname);
```

Here's what each part of the code is doing:

- We import the required Pulumi packages for the task.
- We define variables with the names of resources (`dnsZoneName`, `privateEndpointName`, and `resourceGroupName`) we are going to use. Replace these variables with your actual Azure resource names.
- We retrieve pre-existing resources (DNS Zone and Private Endpoint) using the `get` functions provided by `azure-native` package.
- We create a new CNAME record set using `RecordSet` and set the `cname` property to the FQDN of the private endpoint. The `apply` method is used to handle the asynchronous retrieval of the FQDN from the private endpoint.
- Finally, we export the CNAME record so that it's easily retrievable after you deploy your infrastructure.

Make sure to replace all placeholders with your actual resource details, and consult the [Azure Private DNS Zone](https://www.pulumi.com/docs/reference/pkg/azure-native/network/zones/) and [Private Endpoint](https://www.pulumi.com/docs/reference/pkg/azure-native/network/privateendpoint/) documentation for detailed information on the resources and properties.