Kubernetes Permission to drain a Node from the Node itself

Question

I want to drain a Node from the Node itself. I therefore created a Service Account and added the token to the .kube/config file on the Node. I also creaded the Role Binding.

But I can't figure out the right permissions. I tried this so far but it didn't work.

apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: admin-clusterrole
rules:
- apiGroups: [""]
  resources: ["nodes"]
  verbs: ["drain"]

What would be the correct permissions for that?
Thanks :)

Edit 1:

RoleBinding:

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: node-drainer-clusterrole-bind
  namespace: default
subjects:
- kind: ServiceAccount
  name: node-drainer-sa
  namespace: default
roleRef:
  kind: ClusterRole
  name: system:node-drainer
  apiGroup: rbac.authorization.k8s.io

ServiceAccount:

apiVersion: v1
kind: ServiceAccount
metadata:
  name: node-drainer-sa

Answer 1

First off, you should not use the name admin-clusterrole for this ClusterRole, because you risk locking yourself out of your own cluster by overwriting default bindings.

Here's a ClusterRole which should be able to drain a Node. Let me know if it doesn't work for you.

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: system:node-drainer
rules:
  # Needed to evict pods
  - apiGroups: [""]
    resources: ["pods/eviction"]
    verbs: ["create"]
  # Needed to list pods by Node
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["get", "list"]
  # Needed to cordon Nodes
  - apiGroups: [""]
    resources: ["nodes"]
    verbs: ["get", "patch"]
  # Needed to determine Pod owners
  - apiGroups: ["apps"]
    resources: ["statefulsets"]
    verbs: ["get", "list"]
  # Needed to determine Pod owners
  - apiGroups: ["extensions"]
    resources: ["daemonsets", "replicasets"]
    verbs: ["get", "list"]

You can determine which APIs are used by a kubectl command by using the verbosity levels.

For example:

kubectl drain node my-node -v=10

From here you can inspect the HTTP requests made by kubectl.