install nodelocaldns on managed kubernetes clusters like GKE, EKS, AKS etc

nodelocaldns.sh

#!/usr/bin/env bash

# Example:
#
#   ❯ ./nodelocaldns.sh | kubectl apply -f -
#   serviceaccount/node-local-dns created
#   service/kube-dns-upstream created
#   configmap/node-local-dns created
#   daemonset.apps/node-local-dns created
#

# https://github.com/kubernetes/kubernetes/blob/master/cluster/addons/dns/nodelocaldns/README.md
KUBE_DNS_SERVER_IP=$(kubectl get service -n kube-system kube-dns -o json | jq -r .spec.clusterIP)
KUBE_DNS_DOMAIN="cluster.local"
KUBE_LOCAL_DNS="169.254.20.10"

# https://github.com/kubernetes/kubernetes/pull/84383/files
curl -s https://raw.githubusercontent.com/kubernetes/kubernetes/master/cluster/addons/dns/nodelocaldns/nodelocaldns.yaml \
  | sed -e "s,__PILLAR__DNS__DOMAIN__,${KUBE_DNS_DOMAIN},g" \
  | sed -e "s,__PILLAR__LOCAL__DNS__,${KUBE_LOCAL_DNS},g" \
  | sed -e "s,__PILLAR__DNS__SERVER__,${KUBE_DNS_SERVER_IP},g" \
  | sed -e '\,^\s*kubernetes.io/cluster-service:,d' \
  | sed -e '\,^\s*addonmanager.kubernetes.io/mode:,d'