diff --git a/magnum/drivers/common/templates/kubernetes/fragments/make-cert-client.sh b/magnum/drivers/common/templates/kubernetes/fragments/make-cert-client.sh
index e7debbc38..ca2a7fb8a 100644
--- a/magnum/drivers/common/templates/kubernetes/fragments/make-cert-client.sh
+++ b/magnum/drivers/common/templates/kubernetes/fragments/make-cert-client.sh
@@ -82,7 +82,7 @@ EOF
     curl $VERIFY_CA -X GET \
         -H "X-Auth-Token: $USER_TOKEN" \
         -H "OpenStack-API-Version: container-infra latest" \
-        $MAGNUM_URL/certificates/$CLUSTER_UUID | python -c 'import sys, json; print(json.load(sys.stdin)["pem"])' >> $CA_CERT
+        $MAGNUM_URL/certificates/$CLUSTER_UUID | python -c 'import sys, json; print(json.load(sys.stdin)["pem"])' > $CA_CERT
 
     # Generate client's private key and csr
     $ssh_cmd openssl genrsa -out "${_KEY}" 4096