HDFS-9428. Fix intermittent failure of TestDNFencing.testQueueingWithAppend. Contributed by Masatake Iwasaki.

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -2353,6 +2353,9 @@ Release 2.8.0 - UNRELEASED
 
     HDFS-9024. Deprecate the TotalFiles metric. (Akira Ajisaka via wheat9)
 
+    HDFS-9428. Fix intermittent failure of
+    TestDNFencing.testQueueingWithAppend. (Masatake Iwasaki via waltersu4549)
+
 Release 2.7.3 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestDNFencing.java

@@ -456,6 +456,7 @@ public class TestDNFencing {
       numQueued += numDN * 2; // RBW messages, see comments in case 1
     } finally {
       IOUtils.closeStream(out);
+      cluster.triggerHeartbeats();
       numQueued += numDN; // blockReceived
     }
     assertEquals(numQueued, cluster.getNameNode(1).getNamesystem().