diff --git a/core/src/main/scala/org/apache/spark/deploy/rest/StandaloneRestServer.scala b/core/src/main/scala/org/apache/spark/deploy/rest/StandaloneRestServer.scala
index 3922fbbc60399..e2ec3c3d4bfcf 100644
--- a/core/src/main/scala/org/apache/spark/deploy/rest/StandaloneRestServer.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/rest/StandaloneRestServer.scala
@@ -172,8 +172,10 @@ private[rest] class StandaloneSubmitRequestServlet(
     conf: SparkConf)
   extends SubmitRequestServlet {
 
+  private val envVariablePattern = "\\{\\{([A-Z_]+)\\}\\}".r
+
   private def replacePlaceHolder(variable: String) = variable match {
-    case s"{{$name}}" if System.getenv(name) != null => System.getenv(name)
+    case envVariablePattern(name) if System.getenv(name) != null => System.getenv(name)
     case _ => variable
   }