Integrating Tailscale DNS with Active Directory domain services

Question

Pulumi · Accepted Answer

To integrate Tailscale DNS with Active Directory (AD) domain services, we will be working with Pulumi to create resources that allow Tailscale to use a DNS server that is a part of an Active Directory. This requires setting up Tailscale DNS configuration resources and linking them with the appropriate AD DNS services in the cloud.

Here's an outline of what we're going to do:
1. Set up the Tailscale DNS resources such as `DnsNameservers`, `DnsPreferences`, and `DnsSearchPaths`.
2. Configure the Active Directory services with `ConditionalForwarder` to forward DNS queries properly between the AD domain and Tailscale.
3. Ensure that DNS queries within Tailscale will appropriately resolve AD domain names using the configurations set.

Below is a TypeScript program, using Pulumi, to achieve this integration:

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as tailscale from "@pulumi/tailscale";
import * as aws from "@pulumi/aws";

// Active Directory Directory ID, replace with actual ID.
const directoryId = "d-90670b77d0";

// Assuming Active Directory DNS IP addresses are already known.
const activeDirectoryDnsIps = ["10.0.0.2", "10.0.0.3"];

// Tailscale DNS Nameservers configuration, where you list your AD DNS servers.
// These servers will handle DNS queries within your Tailscale network.
const tsDnsNameservers = new tailscale.DnsNameservers("adDnsNameservers", {
    nameservers: activeDirectoryDnsIps,
});

// Tailscale DNS Preferences configuration, where Magic DNS is enabled or disabled.
// Magic DNS automatically manages hostnames and DNS for your devices within the Tailscale network.
const tsDnsPreferences = new tailscale.DnsPreferences("dnsPreferences", {
    magicDns: true,
});

// Tailscale DNS Search Paths configuration, where you specify search domains that are appended to DNS queries.
const tsDnsSearchPaths = new tailscale.DnsSearchPaths("dnsSearchPaths", {
    searchPaths: ["yourdomain.local"],
});

// AWS Directory Service Conditional Forwarder configuration, which forwards
// DNS queries for a specific domain to the designated DNS servers, here it forwards
// to Active Directory DNS servers IPs that we defined earlier.
const conditionalForwarder = new aws.directoryservice.ConditionalForwarder("adConditionalForwarder", {
    directoryId: directoryId,
    dnsIps: activeDirectoryDnsIps,
    remoteDomainName: "yourdomain.local",
});

// Stack exports for easily retrieving the outputs as needed.
export const nameserverIds = tsDnsNameservers.id;
export const dnsPreferenceSet = tsDnsPreferences.magicDns;
export const dnsSearchPathSet = tsDnsSearchPaths.id;
export const conditionalForwarderId = conditionalForwarder.id;
```

**Explanations:**

- We begin by declaring dependencies on the `@pulumi/pulumi`, `@pulumi/tailscale`, and `@pulumi/aws` packages which allows us to define resources from these providers.

- The `tailscale.DnsNameservers` resource is set up with the IP addresses of our Active Directory DNS servers. Tailscale devices will use these name servers to resolve DNS queries.

- The `tailscale.DnsPreferences` resource includes preferences like Magic DNS which can be toggled as needed.

- The `tailscale.DnsSearchPaths` resource allows us to define custom DNS search paths for Tailscale, which is beneficial when querying short names that are internal to our domain.

- `aws.directoryservice.ConditionalForwarder` is an AWS resource that sets up DNS forwarding rules in cases where we want DNS queries to go through a conditional forwarder, here directing any queries for our domain `yourdomain.local` to our Active Directory DNS servers.

- We finish by exporting some of the key IDs for our resources, allowing us to retrieve their IDs from the Pulumi stack output.

Ensure to replace placeholders like `yourdomain.local` and `directoryId` with actual values from your environment. And, before running this Pulumi program, make sure you have configured your AWS and Tailscale providers with appropriate credentials.

This program establishes the necessary Tailscale and Active Directory configurations using Pulumi, thus integrating both smoothly for DNS resolution.