In this guide, we will find out how to create a new user using the Service Account mechanism of Kubernetes, grant this user admin permissions and login to Dashboard using a bearer token tied to this user.
IMPORTANT: Make sure that you know what you are doing before proceeding. Granting admin privileges to Dashboard's Service Account might be a security risk.
For each of the following snippets for ServiceAccount and ClusterRoleBinding, you should copy them to new manifest files like dashboard-adminuser.yaml and use kubectl apply -f dashboard-adminuser.yaml to create them.
We are creating Service Account with the name admin-user in namespace kubernetes-dashboard first.
apiVersion: v1
kind: ServiceAccount
metadata:
name: admin-user
namespace: kubernetes-dashboardIn most cases after provisioning the cluster using kops, kubeadm or any other popular tool, the ClusterRole cluster-admin already exists in the cluster. We can use it and create only a ClusterRoleBinding for our ServiceAccount.
If it does not exist then you need to create this role first and grant required privileges manually.
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: kubernetes-dashboardNow we need to find the token we can use to log in. Execute the following command:
kubectl -n kubernetes-dashboard get secret $(kubectl -n kubernetes-dashboard get sa/admin-user -o jsonpath="{.secrets[0].name}") -o go-template="{{.data.token | base64decode}}"It should print something like:
eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.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.Z2JrQlitASVwWbc-s6deLRFVk5DWD3P_vjUFXsqVSY10pbjFLG4njoZwh8p3tLxnX_VBsr7_6bwxhWSYChp9hwxznemD5x5HLtjb16kI9Z7yFWLtohzkTwuFbqmQaMoget_nYcQBUC5fDmBHRfFvNKePh_vSSb2h_aYXa8GV5AcfPQpY7r461itme1EXHQJqv-SN-zUnguDguCTjD80pFZ_CmnSE1z9QdMHPB8hoB4V68gtswR1VLa6mSYdgPwCHauuOobojALSaMc3RH7MmFUumAgguhqAkX3Omqd3rJbYOMRuMjhANqd08piDC3aIabINX6gP5-Tuuw2svnV6NYQ
Now copy the token and paste it into the Enter token field on the login screen.
Click the Sign in button and that's it. You are now logged in as an admin.
Remove the admin ServiceAccount and ClusterRoleBinding.
kubectl -n kubernetes-dashboard delete serviceaccount admin-user
kubectl -n kubernetes-dashboard delete clusterrolebinding admin-userIn order to find out more about how to grant/deny permissions in Kubernetes read the official authentication & authorization documentation.
Copyright 2020 The Kubernetes Dashboard Authors

