From 8627f6532baa0488c28514d9dfdd5c4f8bf8f378 Mon Sep 17 00:00:00 2001
From: Akira Ajisaka <aajisaka@apache.org>
Date: Fri, 7 Jun 2019 15:43:38 +0900
Subject: [PATCH] HDFS-14550. RBF: Failed to get statistics from NameNodes
 before 2.9.0. Contributed by He Xiaoqiao.

---
 .../server/federation/router/NamenodeHeartbeatService.java  | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/NamenodeHeartbeatService.java b/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/NamenodeHeartbeatService.java
index d50a5fcdf4..bb601c5889 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/NamenodeHeartbeatService.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/NamenodeHeartbeatService.java
@@ -353,9 +353,9 @@ private void updateJMXParameters(
                 jsonObject.getInt("NumDecommissioningDataNodes"),
                 jsonObject.getInt("NumDecomLiveDataNodes"),
                 jsonObject.getInt("NumDecomDeadDataNodes"),
-                jsonObject.getInt("NumInMaintenanceLiveDataNodes"),
-                jsonObject.getInt("NumInMaintenanceDeadDataNodes"),
-                jsonObject.getInt("NumEnteringMaintenanceDataNodes"));
+                jsonObject.optInt("NumInMaintenanceLiveDataNodes"),
+                jsonObject.optInt("NumInMaintenanceDeadDataNodes"),
+                jsonObject.optInt("NumEnteringMaintenanceDataNodes"));
           } else if (name.equals(
               "Hadoop:service=NameNode,name=FSNamesystem")) {
             report.setNamesystemInfo(