kubernetes-dashboard-user.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: admin-user
  namespace: kube-system

https://gist.github.com/PascalKu/f41d4dde5f0fe16ee83d51f67deda17c/raw/4c500fcc7e2d47aea7555888f2dd7a24f32c631b/kubernetes-dashboard-user.yaml

kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep admin-user | awk '{print $1}')