HDFS-7497. Inconsistent report of decommissioning DataNodes between dfsadmin and NameNode webui. Contributed by Yongjun Zhang.

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

@@ -576,6 +576,9 @@ Release 2.7.0 - UNRELEASED
 
     HDFS-7515. Fix new findbugs warnings in hadoop-hdfs. (wheat9)
 
+    HDFS-7497. Inconsistent report of decommissioning DataNodes between
+    dfsadmin and NameNode webui. (Yongjun Zhang via wang)
+
 Release 2.6.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java

@@ -1112,16 +1112,8 @@ public class DatanodeManager {
   public List<DatanodeDescriptor> getDecommissioningNodes() {
     // There is no need to take namesystem reader lock as
     // getDatanodeListForReport will synchronize on datanodeMap
-    final List<DatanodeDescriptor> decommissioningNodes
-        = new ArrayList<DatanodeDescriptor>();
-    final List<DatanodeDescriptor> results = getDatanodeListForReport(
-        DatanodeReportType.LIVE);
-    for(DatanodeDescriptor node : results) {
-      if (node.isDecommissionInProgress()) {
-        decommissioningNodes.add(node);
-      }
-    }
-    return decommissioningNodes;
+    // A decommissioning DN may be "alive" or "dead".
+    return getDatanodeListForReport(DatanodeReportType.DECOMMISSIONING);
   }
   
   /* Getter and Setter for stale DataNodes related attributes */

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

@@ -239,10 +239,10 @@ public class TestDecommissioningStatus {
       System.setOut(oldOut);
     }
   }
+
   /**
    * Tests Decommissioning Status in DFS.
    */
-
   @Test
   public void testDecommissionStatus() throws IOException, InterruptedException {
     InetSocketAddress addr = new InetSocketAddress("localhost", cluster
@@ -351,6 +351,11 @@ public class TestDecommissioningStatus {
     assertTrue("the node should be DECOMMISSION_IN_PROGRESSS",
         dead.get(0).isDecommissionInProgress());
 
+    // Check DatanodeManager#getDecommissionNodes, make sure it returns
+    // the node as decommissioning, even if it's dead
+    List<DatanodeDescriptor> decomlist = dm.getDecommissioningNodes();
+    assertTrue("The node should be be decommissioning", decomlist.size() == 1);
+    
     // Delete the under-replicated file, which should let the 
     // DECOMMISSION_IN_PROGRESS node become DECOMMISSIONED
     cleanupFile(fileSys, f);