Specify k8s-bootstrap-admin as the serviceAccountName.

 ---
 apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: k8s-bootstrap-admin
+  namespace: kube-system
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: k8s-bootstrap-admin
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: ClusterRole
+  name: cluster-admin
+subjects:
+  - kind: ServiceAccount
+    name: k8s-bootstrap-admin
+    namespace: kube-system
+---
+apiVersion: v1
 kind: ConfigMap
 metadata:
   name: k8s-bootstrap-config
@@ -66,6 +85,8 @@ spec:
       - effect: NoSchedule
         key: node-role.kubernetes.io/master
 
+      serviceAccountName: k8s-bootstrap-admin
+
       volumes:
         - name: k8s-bootstrap-ssh-config
           configMap: