diff --git a/setup/so-functions b/setup/so-functions
index 0cfb5ded2..d7252bb53 100755
--- a/setup/so-functions
+++ b/setup/so-functions
@@ -844,7 +844,7 @@ docker_registry() {
 	if [ -n "$TURBO" ]; then local proxy="$TURBO"; else local proxy="https://$MSRV"; fi
 	printf '%s\n'\
 		"{"\
-		"  \"registry-mirrors\": [ \"$proxy:5000\" ]"\
+		"  \"registry-mirrors\": [ \"$proxy:5000\" ],"\
 		"  \"default-address-pools\": ["\
 		"    {"\
 		"      \"base\" : \"$DOCKERNET\","\