diff --git a/certbotd.sh b/certbotd.sh
index ce21078..35b4b77 100755
--- a/certbotd.sh
+++ b/certbotd.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-if test -z "${NODES}"; then
+if test -z "${NODES}" && test -z "${SINGLE_NODE}"; then
   echo "The env var NODES is empty, if you don't want to synchronize to other servers, set SINGLE_NODE=true" >&2
   exit 1
 fi