https://github.com/kubernetes/kubernetes/blob/6a8a3682919652ae668c389ed2f60efb770eed03/staging/src/k8s.io/client-go/tools/clientcmd/validation.go#L48-L56
https://github.com/kubernetes/kubernetes/blob/6a8a3682919652ae668c389ed2f60efb770eed03/staging/src/k8s.io/client-go/tools/clientcmd/validation.go#L60-L66
