Fix for systemd-resolved DNS incompatibility

This problem occurs because systems using systemd-resolved copy
127.0.0.53 from the host's /etc/resolv.conf.

More discussion here: kubernetes/kubernetes#45828

Related issues:
kubernetes/kubeadm#787
kubernetes/kubeadm#273
kubernetes/kubeadm#845

The upstream fix is now in v1.11.

Author: vannrt

constants/constants.go

@@ -63,7 +63,7 @@ const (
 	NodeadmKubeletSystemdDropinFilename = "20-nodeadm.conf"
 	NodeadmKubeletSystemdDropinTemplate = `[Service]
 Environment="KUBELET_DNS_ARGS=--cluster-dns={{ .ClusterDNS }} --cluster-domain={{ .ClusterDomain }}"
-Environment="KUBELET_EXTRA_ARGS=--max-pods={{ .MaxPods }} --fail-swap-on={{ .FailSwapOn }} --hostname-override={{ .HostnameOverride }} --kube-api-qps={{ .KubeAPIQPS }} --kube-api-burst={{ .KubeAPIBurst }} --feature-gates={{ .FeatureGates}} --eviction-hard={{ .EvictionHard }}"
+Environment="KUBELET_EXTRA_ARGS=--resolv-conf=/run/systemd/resolve/resolv.conf --max-pods={{ .MaxPods }} --fail-swap-on={{ .FailSwapOn }} --hostname-override={{ .HostnameOverride }} --kube-api-qps={{ .KubeAPIQPS }} --kube-api-burst={{ .KubeAPIBurst }} --feature-gates={{ .FeatureGates}} --eviction-hard={{ .EvictionHard }}"
 `
 )