diff --git a/yarn/alpha/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala b/yarn/alpha/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
index bb574f415293a88121e7e17c861511ddc683db42..87785cdc60c528bc12597bf75d9c966d5510fefc 100644
--- a/yarn/alpha/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
+++ b/yarn/alpha/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
@@ -79,6 +79,9 @@ class ApplicationMaster(args: ApplicationMasterArguments, conf: Configuration,
     // other spark processes running on the same box
     System.setProperty("spark.ui.port", "0")
 
+    // when running the AM, the Spark master is always "yarn-cluster"
+    System.setProperty("spark.master", "yarn-cluster")
+
     // Use priority 30 as its higher then HDFS. Its same priority as MapReduce is using.
     ShutdownHookManager.get().addShutdownHook(new AppMasterShutdownHook(this), 30)
 
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 b48a2d50db5efbe47e1f943ea5c9fab274392476..57d15774290dd7daac109fe9f484eb7aacdbb73a 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
@@ -82,6 +82,9 @@ class ApplicationMaster(args: ApplicationMasterArguments, conf: Configuration,
     // other spark processes running on the same box
     System.setProperty("spark.ui.port", "0")
 
+    // when running the AM, the Spark master is always "yarn-cluster"
+    System.setProperty("spark.master", "yarn-cluster")
+
     // Use priority 30 as it's higher then HDFS. It's same priority as MapReduce is using.
     ShutdownHookManager.get().addShutdownHook(new AppMasterShutdownHook(this), 30)