The mount path for the id needs to be correct.

@@ -86,8 +86,8 @@ spec:
             - name: cluster-ssh
               mountPath: /tmp/cluster-home/.ssh
             - name: k8s-bootstrap-ssh-auth
-              mountPath: /tmp/cluster-home/.ssh/id
-              subPath: id
+              mountPath: /tmp/cluster-home/.ssh/id_rsa
+              subPath: id_rsa
             - name: k8s-bootstrap-ssh-config
               mountPath: /tmp/cluster-home/.ssh/config
               subPath: config