Kubernetes RBAC - forbidden attempt to grant extra privileges

I'm using Kubernetes v1.8.14 on custom built CoreOS cluster:

$ kubectl version --short 
Client Version: v1.10.5
Server Version: v1.8.14+coreos.0

When trying to create the following ClusterRole:

$ cat ClusterRole.yml 
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:coredns
rules:
- apiGroups:
  - ""
  resources:
  - endpoints
  - services
  - pods
  - namespaces
  verbs:
  - list
  - watch

I get the following error:

$ kubectl create -f ClusterRole.yml 
Error from server (Forbidden): error when creating "ClusterRole.yml": clusterroles.rbac.authorization.k8s.io "system:coredns" is forbidden: attempt to grant extra privileges: [PolicyRule{Resources:["endpoints"], APIGroups:[""], Verbs:["list"]} PolicyRule{Resources:["endpoints"], APIGroups:[""], Verbs:["watch"]} PolicyRule{Resources:["services"], APIGroups:[""], Verbs:["list"]} PolicyRule{Resources:["services"], APIGroups:[""], Verbs:["watch"]} PolicyRule{Resources:["pods"], APIGroups:[""], Verbs:["list"]} PolicyRule{Resources:["pods"], APIGroups:[""], Verbs:["watch"]} PolicyRule{Resources:["namespaces"], APIGroups:[""], Verbs:["list"]} PolicyRule{Resources:["namespaces"], APIGroups:[""], Verbs:["watch"]}] user=&{cluster-admin  [system:authenticated] map[]} ownerrules=[PolicyRule{Resources:["selfsubjectaccessreviews"], APIGroups:["authorization.k8s.io"], Verbs:["create"]} PolicyRule{NonResourceURLs:["/api" "/api/*" "/apis" "/apis/*" "/healthz" "/swagger-2.0.0.pb-v1" "/swagger.json" "/swaggerapi" "/swaggerapi/*" "/version"], Verbs:["get"]}] ruleResolutionErrors=[]

As far as I can tell I'm connecting as cluster-admin, therefore should have sufficient permissions for what I'm trying to achieve. Below are relevant cluster-admin config:

$ cat ~/.kube/config
apiVersion: v1
kind: Config
current-context: dev
preferences:
  colors: true

clusters:
- cluster:
    certificate-authority: cluster-ca.pem
    server: https://k8s.loc:4430
  name: dev

contexts:
- context:
    cluster: dev
    namespace: kube-system
    user: cluster-admin
  name: dev

users:
- name: cluster-admin
  user:
    client-certificate: cluster.pem
    client-key: cluster-key.pem


$ kubectl get clusterrole cluster-admin -o yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  creationTimestamp: 2018-07-30T14:44:44Z
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: cluster-admin
  resourceVersion: "1164791"
  selfLink: /apis/rbac.authorization.k8s.io/v1/clusterroles/cluster-admin
  uid: 196ffecc-9407-11e8-bd67-525400ac0b7d
rules:
- apiGroups:
  - '*'
  resources:
  - '*'
  verbs:
  - '*'
- nonResourceURLs:
  - '*'
  verbs:
  - '*'


$ kubectl get clusterrolebinding cluster-admin -o yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  creationTimestamp: 2018-07-30T14:44:45Z
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: cluster-admin
  resourceVersion: "1164832"
  selfLink: /apis/rbac.authorization.k8s.io/v1/clusterrolebindings/cluster-admin
  uid: 19e516a6-9407-11e8-bd67-525400ac0b7d
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: Group
  name: system:masters


$ kubectl get serviceaccount cluster-admin -o yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  creationTimestamp: 2018-07-30T13:32:13Z
  name: cluster-admin
  namespace: kube-system
  resourceVersion: "1158783"
  selfLink: /api/v1/namespaces/kube-system/serviceaccounts/cluster-admin
  uid: f809e079-93fc-11e8-8b85-525400546bcd
secrets:
- name: cluster-admin-token-t7s4c

I understand this is RBAC problem, but have no idea how further debug this.

Edit-1.

I tried the suggested, no joy unfortunately...

$ kubectl get clusterrolebinding cluster-admin-binding -o yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  creationTimestamp: 2018-07-31T09:21:34Z
  name: cluster-admin-binding
  resourceVersion: "1252260"
  selfLink: /apis/rbac.authorization.k8s.io/v1/clusterrolebindings/cluster-admin-binding
  uid: 1e1c0647-94a3-11e8-9f9b-525400ac0b7d
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: cluster-admin
  namespace: default


$ kubectl describe secret $(kubectl get secret | awk '/cluster-admin/{print $1}')
Name:         cluster-admin-token-t7s4c
Namespace:    kube-system
Labels:       <none>
Annotations:  kubernetes.io/service-account.name=cluster-admin
              kubernetes.io/service-account.uid=f809e079-93fc-11e8-8b85-525400546bcd

Type:  kubernetes.io/service-account-token

Data
====
ca.crt:     1785 bytes
namespace:  11 bytes
token:      eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.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.rC1x9Or8GArkhC3P0s-l_Pc0e6TEUwfbJtXAN2w-cOaRUCNCo6r4WxXKu32ngOg86TXqCho2wBopXtbJ2CparIb7FWDXzri6O6LPFzHWNzZo3b-TON2yxHMWECGjpbbqjDgkPKDEldkdxJehDBJM_GFAaUdNyYpFFsP1_t3vVIsf2DpCjeMlOBSprYRcEKmDiE6ehF4RSn1JqB7TVpvTZ_WAL4CRZoTJtZDVoF75AtKIADtVXTxVv_ewznDCKUWDupg5Jk44QSMJ0YiG30QYYM699L5iFLirzD5pj0EEPAoMeOqSjdp7KvDzIM2tBiu8YYl6Fj7pG_53WjZrvlSk5pgPLS-jPKOkixFM9FfB2eeuP0eWwLO5wvU5s--a2ekkEhaqHTXgigeedudDA_5JVIJTS0m6V9gcbE4_kYRpU7_QD_0TR68C5yxUL83KfOzj6A_S6idOZ-p7Ni6ffE_KlGqqcgUUR2MTakJgimjn0gYHNaIqmHIu4YhrT-jffP0-5ZClbI5srj-aB4YqGtCH9w5_KBYD4S2y6Rjv4kO00nZyvi0jAHlZ6el63TQPWYkjyPL2moF_P8xcPeoDrF6o8bXDzFqlXLqda2Nqyo8LMhLxjpe_wFeGuwzIUxwwtH1RUR6BISRUf86041aa2PeJMqjTfaU0u_SvO-yHMGxZt3o

Then amended ~/.kube/config:

$ cat ~/.kube/config
apiVersion: v1
kind: Config
current-context: dev
preferences:
  colors: true

clusters:
- cluster:
    certificate-authority: cluster-ca.pem
    server: https://k8s.loc:4430
  name: dev

contexts:
- context:
    cluster: dev
    namespace: kube-system
    user: cluster-admin-2
  name: dev

users:
- name: cluster-admin
  user:
    client-certificate: cluster.pem
    client-key: cluster-key.pem
- name: cluster-admin-2
  user:
    token: eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.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.rC1x9Or8GArkhC3P0s-l_Pc0e6TEUwfbJtXAN2w-cOaRUCNCo6r4WxXKu32ngOg86TXqCho2wBopXtbJ2CparIb7FWDXzri6O6LPFzHWNzZo3b-TON2yxHMWECGjpbbqjDgkPKDEldkdxJehDBJM_GFAaUdNyYpFFsP1_t3vVIsf2DpCjeMlOBSprYRcEKmDiE6ehF4RSn1JqB7TVpvTZ_WAL4CRZoTJtZDVoF75AtKIADtVXTxVv_ewznDCKUWDupg5Jk44QSMJ0YiG30QYYM699L5iFLirzD5pj0EEPAoMeOqSjdp7KvDzIM2tBiu8YYl6Fj7pG_53WjZrvlSk5pgPLS-jPKOkixFM9FfB2eeuP0eWwLO5wvU5s--a2ekkEhaqHTXgigeedudDA_5JVIJTS0m6V9gcbE4_kYRpU7_QD_0TR68C5yxUL83KfOzj6A_S6idOZ-p7Ni6ffE_KlGqqcgUUR2MTakJgimjn0gYHNaIqmHIu4YhrT-jffP0-5ZClbI5srj-aB4YqGtCH9w5_KBYD4S2y6Rjv4kO00nZyvi0jAHlZ6el63TQPWYkjyPL2moF_P8xcPeoDrF6o8bXDzFqlXLqda2Nqyo8LMhLxjpe_wFeGuwzIUxwwtH1RUR6BISRUf86041aa2PeJMqjTfaU0u_SvO-yHMGxZt3o

And then tried to apply the same ClusterRole, which rendered the same error:

$ kubectl apply -f ClusterRole.yml 
Error from server (Forbidden): error when creating "ClusterRole.yml": clusterroles.rbac.authorization.k8s.io "system:coredns" is forbidden: attempt to grant extra privileges: [PolicyRule{Resources:["endpoints"], APIGroups:[""], Verbs:["list"]} PolicyRule{Resources:["endpoints"], APIGroups:[""], Verbs:["watch"]} PolicyRule{Resources:["services"], APIGroups:[""], Verbs:["list"]} PolicyRule{Resources:["services"], APIGroups:[""], Verbs:["watch"]} PolicyRule{Resources:["pods"], APIGroups:[""], Verbs:["list"]} PolicyRule{Resources:["pods"], APIGroups:[""], Verbs:["watch"]} PolicyRule{Resources:["namespaces"], APIGroups:[""], Verbs:["list"]} PolicyRule{Resources:["namespaces"], APIGroups:[""], Verbs:["watch"]}] user=&{system:serviceaccount:kube-system:cluster-admin f809e079-93fc-11e8-8b85-525400546bcd [system:serviceaccounts system:serviceaccounts:kube-system system:authenticated] map[]} ownerrules=[PolicyRule{Resources:["selfsubjectaccessreviews"], APIGroups:["authorization.k8s.io"], Verbs:["create"]} PolicyRule{NonResourceURLs:["/api" "/api/*" "/apis" "/apis/*" "/healthz" "/swagger-2.0.0.pb-v1" "/swagger.json" "/swaggerapi" "/swaggerapi/*" "/version"], Verbs:["get"]}] ruleResolutionErrors=[]

Below are the flags which I use to start apiserver:

  containers:
    - name: kube-apiserver
      image: quay.io/coreos/hyperkube:${K8S_VER}
      command:
        - /hyperkube
        - apiserver
        - --bind-address=0.0.0.0
        - --etcd-servers=${ETCD_ENDPOINTS}
        - --allow-privileged=true
        - --service-cluster-ip-range=${SERVICE_IP_RANGE}
        - --secure-port=443
        - --advertise-address=${ADVERTISE_IP}
        - --admission-control=NamespaceLifecycle,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota
        - --tls-cert-file=/etc/kubernetes/ssl/apiserver.pem
        - --tls-private-key-file=/etc/kubernetes/ssl/apiserver-key.pem
        - --client-ca-file=/etc/kubernetes/ssl/ca.pem
        - --service-account-key-file=/etc/kubernetes/ssl/apiserver-key.pem
        - --runtime-config=extensions/v1beta1/networkpolicies=true
        - --anonymous-auth=false
        - --authorization-mode=AlwaysAllow,RBAC,Node

And here are the scripts, which I use to generate my tls certs:

root ca:

openssl genrsa -out ca-key.pem 4096
openssl req -x509 -new -nodes -key ca-key.pem -days 3650 -out ca.pem -subj "/CN=kube-ca"

apiserver:

cat > openssl.cnf <<EOF
[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name

[req_distinguished_name]

[v3_req]
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
subjectAltName = @alt_names

[alt_names]
DNS.1 = kubernetes
DNS.2 = kubernetes.default
DNS.3 = kubernetes.default.svc
DNS.4 = kubernetes.default.svc.cluster.local
DNS.5 = ${MASTER_LB_DNS}
IP.1 = ${K8S_SERVICE_IP}
IP.2 = ${MASTER_HOST}
EOF

openssl genrsa -out apiserver-key.pem 4096
openssl req -new -key apiserver-key.pem -out apiserver.csr -subj "/CN=kube-apiserver" -config openssl.cnf
openssl x509 -req -in apiserver.csr -CA ca.pem -CAkey ca-key.pem -CAcreateserial -out apiserver.pem -days 3650 -extensions v3_req -extfile openssl.cnf

cluster-admin:

openssl genrsa -out cluster-admin-key.pem 4096
openssl req -new -key cluster-admin-key.pem -out cluster-admin.csr -subj "/CN=cluster-admin"
openssl x509 -req -in cluster-admin.csr -CA ca.pem -CAkey ca-key.pem -CAcreateserial -out cluster-admin.pem -days 3650

I hope this gives you more insight, what's wrong with my system.

Edit-2.

I noted a slight discrepancy between my system configuration and what @MarcinRomaszewicz suggested, thus the namespace of the cluster-admin ServiceAccount, in my case it is in the kube-system as opposed to the default namespace:

$ kubectl delete clusterrolebinding cluster-admin-binding 
clusterrolebinding.rbac.authorization.k8s.io "cluster-admin-binding" deleted

$ kubectl create clusterrolebinding cluster-admin-binding \
 --clusterrole=cluster-admin --serviceaccount=kube-system:cluster-admin
clusterrolebinding.rbac.authorization.k8s.io "cluster-admin-binding" created

$ kubectl apply -f ClusterRole.yml 
clusterrole.rbac.authorization.k8s.io "system:coredns" created

However it still doesn't work with my certificates...

Edit-3.

As suggested in the comments, in order for apiserver to recognize the user as the cluster-admin, Subject line in the certificate of that user must contain the following items: Subject: CN = cluster-admin, O = system:masters. One way to generate such a certificate is as follows:

openssl genrsa -out cluster-admin-key.pem 4096
openssl req -new -key cluster-admin-key.pem -out cluster-admin.csr -subj "/CN=cluster-admin/O=system:masters"
openssl x509 -req -in cluster-admin.csr -CA ca.pem -CAkey ca-key.pem -CAcreateserial -out cluster-admin.pem -days 3650

Edit-1.

Edit-2.

Edit-3.

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