openssl genrsa -out martin.key 2048
 openssl req -new -key martin.key -out martin.csr -subj "/CN=martin/O=developer"

cp /etc/kubernetes/pki/ca.crt .
cp /etc/kubernetes/pki/ca.key .

openssl x509 -req -in martin.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out martin.crt -days 3540

kubectl config get-users
 kubectl config set-credentials jean   --client-certificate=/home/jean/.certs/jean.crt   --client-key=martin.key
  kubectl config set-credentials martin   --client-certificate=martin.crt   --client-key=martin.key
  kubectl config get-users

  kubectl create role developer-role --verb=* --resource=*
   kubectl describe role developer-role -n development

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: role-grantor-binding
  namespace: user-1-namespace
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: role-grantor
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: User
  name: user-1

 https://www.adaltas.com/en/2019/08/07/users-rbac-kubernetes/

apiVersion: v1
clusters:
- cluster:
   certificate-authority-data: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUMvakNDQWVhZ0F3SUJBZ0lCQURBTkJna3Foa2lHOXcwQkFRc0ZBREFWTVJNd0VRWURWUVFERXdwcmRXSmwKY201bGRHVnpNQjRYRFRJeU1URXlOekl6TVRjME1Gb1hEVE15TVRFeU5ESXpNVGMwTUZvd0ZURVRNQkVHQTFVRQpBeE1LYTNWaVpYSnVaWFJsY3pDQ0FTSXdEUVlKS29aSWh2Y05BUUVCQlFBRGdnRVBBRENDQVFvQ2dnRUJBTkpkClFIRGpDVFNHMC92UHcrWHZNOGhhRlBxdlEvYm5vdEZNeWYwVlZXelk4MUZXQ0Z5NmI2dHZ4VHhWaXZZRVBQRXEKSDFQTldzZ2l1QStMOGlRNTUvQzBjM1crSEJy
   server: https://controlplane:6443
 name: kubernetes
contexts:
- context:
   cluster: kubernetes
   user: kubernetes-admin
 name: kubernetes-admin@kubernetes
- context:    
   cluster: kubernetes
   user: martin
 name: developer
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: jean
 user:
   client-certificate: /home/jean/.certs/jean.crt
   client-key: /root/martin.key
- name: kubernetes-admin
 user:
   client-certificate-data: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSURJVENDQWdtZ0F3SUJBZ0lJWWNaMEVqVDVuN0F3RFFZSktvWklodmNOQVFFTEJRQXdGVEVUTUJFR0ExVUUKQXhNS2EzVmlaWEp1WlhSbGN6QWVGdzB5TWpFeE1qY3lNekUzTkRCYUZ3MHlNekV4TWpjeU16RTNOREphTURReApGekFWQmdOVkJBb1REbk41YzNSbGJUcHRZWE4wWlhKek1Sa3dGd1lEVlFRREV4QnJkV0psY201bGRHVnpMV0ZrCmJXbHVNSUlCSWpBTkJna3Foa2lHOXcwQkFRRUZBQU9DQVE4QU1JSUJDZ
   client-key-data: LS0tLS1CRUdJTiBSU0EgUFJJVkFURSBLRVktLS0tLQpNSUlFcEFJQkFBS0NBUUVBNXJKdU9kQVNiZjVuWEFvZkFvR2xNVTRjcEZSVTR0RkRVNjlJMUZqK01ITmd2QVV4ClhNZTN6OUR2V2VGZzlhejBabUFucUI0RkFBRHN2TkpuUGJzTVNRNEVpcmlwQ2U0SHNJcWNrT0kwcWZvdzN
- name: martin
 user:
   client-certificate: /root/martin.crt
   client-key: /root/martin.key