diff --git a/appengine/extending-runtime/Dockerfile b/appengine/extending-runtime/Dockerfile
index ea3b43825a..cd2223d311 100755
--- a/appengine/extending-runtime/Dockerfile
+++ b/appengine/extending-runtime/Dockerfile
@@ -15,4 +15,4 @@ COPY . /app/
 RUN npm --unsafe-perm install
 
 # Run the app, default is "npm start"
-CMD npm start-on-prod
+CMD npm run start-on-prod