Additional Considerations for coredns When Tailscale is Installed

  • Edit the config map:
kubectl edit configmap coredns -n kube-system

  • Look for a line that says forward .

  • Change the line to look like this to pull from Cloudflare’s DNS:

forward . 1.1.1.1
  • Once saved and exited, manually restart the coredns pods with:
kubectl rollout restart deployment coredns -n kube-system
  • Good command for checking the last x amount of logs a pod generated:
kubectl logs -n kube-system -l k8s-app=kube-dns --tail=100
  • Good tests to check for DNS from within a pod:
kubectl exec -n metalinux-docs -it busybox-dns-test -- /bin/sh

# Try internal DNS
nslookup kubernetes.default

# Try external DNS (via CoreDNS)
nslookup cloudflare.com

# Ping CoreDNS IP directly
ping 10.96.0.10

Updated: