enable back kubelet_authorization_mode_webhook by default (#9662)

In 6db6c867, this was disabled becaue
kubesrpay gave too much permissions that were not needed. This commit
re-enable back this option by default and also removes the extra
permissions that kubespray gave that were in fact not needed.

Signed-off-by: Arthur Outhenin-Chalandre <arthur.outhenin-chalandre@proton.ch>

Signed-off-by: Arthur Outhenin-Chalandre <arthur.outhenin-chalandre@proton.ch>

docs/hardening.md

@@ -85,6 +85,7 @@ kube_kubeadm_scheduler_extra_args:
 etcd_deployment_type: kubeadm
 
 ## kubelet
+kubelet_authorization_mode_webhook: true
 kubelet_authentication_token_webhook: true
 kube_read_only_port: 0
 kubelet_rotate_server_certificates: true

roles/kubernetes-apps/cluster_roles/tasks/main.yml

@@ -37,55 +37,25 @@
     - node_crb_manifest.changed
     - inventory_hostname == groups['kube_control_plane'][0]
 
-- name: Kubernetes Apps | Add webhook ClusterRole that grants access to proxy, stats, log, spec, and metrics on a kubelet
-  template:
-    src: "node-webhook-cr.yml.j2"
-    dest: "{{ kube_config_dir }}/node-webhook-cr.yml"
-    mode: 0640
-  register: node_webhook_cr_manifest
-  when:
-    - rbac_enabled
-    - kubelet_authorization_mode_webhook
-    - inventory_hostname == groups['kube_control_plane'][0]
-  tags: node-webhook
-
-- name: Apply webhook ClusterRole
+- name: Kubernetes Apps | Remove old webhook ClusterRole
   kube:
     name: "system:node-webhook"
     kubectl: "{{ bin_dir }}/kubectl"
     resource: "clusterrole"
-    filename: "{{ kube_config_dir }}/node-webhook-cr.yml"
-    state: latest
+    state: absent
   when:
     - rbac_enabled
-    - kubelet_authorization_mode_webhook
-    - node_webhook_cr_manifest.changed
     - inventory_hostname == groups['kube_control_plane'][0]
   tags: node-webhook
 
-- name: Kubernetes Apps | Add ClusterRoleBinding for system:nodes to webhook ClusterRole
-  template:
-    src: "node-webhook-crb.yml.j2"
-    dest: "{{ kube_config_dir }}/node-webhook-crb.yml"
-    mode: 0640
-  register: node_webhook_crb_manifest
-  when:
-    - rbac_enabled
-    - kubelet_authorization_mode_webhook
-    - inventory_hostname == groups['kube_control_plane'][0]
-  tags: node-webhook
-
-- name: Grant system:nodes the webhook ClusterRole
+- name: Kubernetes Apps | Remove old webhook ClusterRoleBinding
   kube:
     name: "system:node-webhook"
     kubectl: "{{ bin_dir }}/kubectl"
     resource: "clusterrolebinding"
-    filename: "{{ kube_config_dir }}/node-webhook-crb.yml"
-    state: latest
+    state: absent
   when:
     - rbac_enabled
-    - kubelet_authorization_mode_webhook
-    - node_webhook_crb_manifest.changed
     - inventory_hostname == groups['kube_control_plane'][0]
   tags: node-webhook
 

roles/kubernetes-apps/cluster_roles/templates/node-webhook-cr.yml.j2

----
-apiVersion: rbac.authorization.k8s.io/v1
-kind: ClusterRole
-metadata:
-  annotations:
-    rbac.authorization.kubernetes.io/autoupdate: "true"
-  labels:
-    kubernetes.io/bootstrapping: rbac-defaults
-  name: system:node-webhook
-rules:
-  - apiGroups:
-      - ""
-    resources:
-      - nodes/proxy
-      - nodes/stats
-      - nodes/log
-      - nodes/spec
-      - nodes/metrics
-    verbs:
-      - "*"

roles/kubernetes-apps/cluster_roles/templates/node-webhook-crb.yml.j2

----
-apiVersion: rbac.authorization.k8s.io/v1
-kind: ClusterRoleBinding
-metadata:
-  annotations:
-    rbac.authorization.kubernetes.io/autoupdate: "true"
-  labels:
-    kubernetes.io/bootstrapping: rbac-defaults
-  name: system:node-webhook
-roleRef:
-  apiGroup: rbac.authorization.k8s.io
-  kind: ClusterRole
-  name: system:node-webhook
-subjects:
-- apiGroup: rbac.authorization.k8s.io
-  kind: Group
-  name: system:nodes

roles/kubespray-defaults/defaults/main.yaml

@@ -480,7 +480,7 @@ rbac_enabled: "{{ 'RBAC' in authorization_modes }}"
 kubelet_authentication_token_webhook: true
 
 # When enabled, access to the kubelet API requires authorization by delegation to the API server
-kubelet_authorization_mode_webhook: false
+kubelet_authorization_mode_webhook: true
 
 # kubelet uses certificates for authenticating to the Kubernetes API
 # Automatically generate a new key and request a new certificate from the Kubernetes API as the current certificate approaches expiration