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Enable MagicDNS resolution in your cluster

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By default, pods in your Kubernetes cluster cannot resolve Tailscale MagicDNS names (.ts.net). If your egress targets use HTTPS, the TLS certificate is issued for the MagicDNS name. For example, my-database.<tailnet>.ts.net, and your workloads need to connect using that name for certificate validation to succeed.

This guide describes how to deploy a DNSConfig resource to enable .ts.net resolution from within your cluster.

Prerequisites

Before you begin, make sure you have the following:

Deploy the DNSConfig resource

Create a DNSConfig resource to deploy the in-cluster nameserver:

apiVersion: tailscale.com/v1alpha1
kind: DNSConfig
metadata:
  name: ts-dns
spec:
  nameserver:
    image:
      repo: tailscale/k8s-nameserver
      tag: unstable

Apply the manifest to your cluster:

kubectl apply -f dnsconfig.yaml

Get the nameserver IP

After the nameserver is running, its ClusterIP is written to the DNSConfig status:

kubectl get dnsconfig ts-dns -o jsonpath='{.status.nameserver.ip}'

Configure CoreDNS

Add a stub domain to your CoreDNS configuration so that .ts.net queries are forwarded to the Tailscale nameserver.

Edit the CoreDNS ConfigMap:

kubectl edit configmap coredns -n kube-system

Add a ts.net server block that forwards to the nameserver IP from the previous step:

ts.net:53 {
    errors
    cache 30
    forward . <nameserver-ip>
}

Restart CoreDNS to pick up the change:

kubectl rollout restart deployment coredns -n kube-system

If your cluster uses kube-dns instead of CoreDNS (for example, some GKE configurations), refer to the GKE documentation for stub domain configuration.

Verify name resolution

Test that .ts.net names resolve from within the cluster:

kubectl run -it --rm dns-test --image=busybox -- nslookup <device>.<tailnet>.ts.net

Replace <device>.<tailnet>.ts.net with the MagicDNS name of a tailnet device that has an egress proxy configured. If the lookup returns the egress proxy pod IP, MagicDNS resolution is working.

Further exploration