K8s WebUI - Creating sample user

In this guide, we will find out how to create a new user using Service Account mechanism of Kubernetes, grant this user admin permissions and login to Dashboard using 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.

Creating a Service Account

We are creating Service Account with name admin-user in namespace kubernetes-dashboard first.

apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kubernetes-dashboard

Creating a ClusterRoleBinding

In most cases after provisioning 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 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-dashboard

Getting a Bearer Token

Now we need to find token we can use to log in. Execute 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 Enter token field on the login screen.

Click Sign in button and that’s it. You are now logged in as an admin.

Clean up and next steps

Remove the admin ServiceAccount and ClusterRoleBinding.

kubectl -n kubernetes-dashboard delete serviceaccount admin-user
kubectl -n kubernetes-dashboard delete clusterrolebinding admin-user

In order to find out more about how to grant/deny permissions in Kubernetes read official authentication & authorization documentation.

Copyright 2020 The Kubernetes Dashboard Authors