diff --git a/setup_managed_node.sh b/setup_managed_node.sh
index 30d5dd2..c261843 100644
--- a/setup_managed_node.sh
+++ b/setup_managed_node.sh
@@ -62,7 +62,7 @@
 chmod 700 "${KEY_TMP_DIR}"
 KEY_TMP_PATH="${KEY_TMP_DIR}/id_${KEY_TYPE}"
 
-KEY_COMMENT="ansible-bootstrap $(date -u +%Y-%m-%d %H:%M:%SZ)"
+KEY_COMMENT="ansible-bootstrap $(date -u "+%Y-%m-%d %H:%M:%SZ")"
 
 ssh-keygen \
   -t "${KEY_TYPE}" \