apiserver-to-node

Create the `system:kube-apiserver-to-kubelet` [ClusterRole](https://kubernetes.io/docs/admin/authorization/rbac/#role-and-clusterrole) with permissions to access the Kubelet API and perform most common tasks associated with managing pods:

```
cat <<EOF | kubectl apply --kubeconfig admin.kubeconfig -f -
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:kube-apiserver-to-kubelet
rules:
  - apiGroups:
      - ""
    resources:
      - nodes/proxy
      - nodes/stats
      - nodes/log
      - nodes/spec
      - nodes/metrics
    verbs:
      - "*"
EOF
```

The Kubernetes API Server authenticates to the Kubelet as the `kubernetes` user using the client certificate as defined by the `--kubelet-client-certificate` flag.

Bind the `system:kube-apiserver-to-kubelet` ClusterRole to the `kubernetes` user:

```
cat <<EOF | kubectl apply --kubeconfig admin.kubeconfig -f -
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: system:kube-apiserver
  namespace: ""
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:kube-apiserver-to-kubelet
subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: User
    name: kube-apiserver
EOF
```