diff --git a/yarn/stable/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala b/yarn/stable/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
index 6244332f23737..bd9eed57301a5 100644
--- a/yarn/stable/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
+++ b/yarn/stable/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
@@ -164,6 +164,7 @@ class ApplicationMaster(args: ApplicationMasterArguments, conf: Configuration,
 
   private def startUserClass(): Thread = {
     logInfo("Starting the user JAR in a separate Thread")
+    System.setProperty("spark.executor.instances",args.numExecutors.toString)
     val mainMethod = Class.forName(
       args.userClass,
       false,