Deploy latest metric-server release.
kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.5.0/components.yaml
You need to add argument --kubelet-insecure-tls
to the metrics-server container.
kubectl patch -n kube-system deployment metrics-server --type=json \
-p '[{"op":"add","path":"/spec/template/spec/containers/0/args/-","value":"--kubelet-insecure-tls"}]'