K8s metrics server

To get the metrics of nodes

$ kubectl top nodes
error: Metrics API not available

We should install metrics-server
https://github.com/kubernetes-sigs/metrics-server

https://github.com/kubernetes-sigs/metrics-server/issues/1025

E0502 00:40:51.819552       1 scraper.go:140] "Failed to scrape node" err="Get \"https://192.168.49.2:10250/metrics/resource\": x509: cannot validate certificate for 192.168.49.2 because it doesn't contain any IP SANs" node="minikube"

192.168.49.2 is the node ip