<p>For default service account I have creating clusterrolebinding for cluster role=cluster-admin <br>using below kubectl command</p>
<pre><code>kubectl create clusterrolebinding add-on-cluster-admin --clusterrole=cluster-admin --serviceaccount=rbac-test:default
</code></pre>
<p>cluster-admin role is bind to default service account. <br>
How to unbind it again from service account?</p>

<p>When you run your <code>kubectl</code> command it creates the following object:</p>
<pre><code>apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  creationTimestamp: null
  name: add-on-cluster-admin
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: default
  namespace: rbac-test
</code></pre>
<p>You should be able to just delete that object:</p>
<pre><code>kubectl delete clusterrolebinding add-on-cluster-admin
</code></pre>
