HDFS-4127. Log message is not correct in case of short of replica. Contributed by Junping Du.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1403616 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -522,6 +522,9 @@ Release 2.0.3-alpha - Unreleased
     HDFS-3616. Fix a ConcurrentModificationException bug that BP actor threads
     may not be shutdown properly in DataNode.  (Jing Zhao via szetszwo)
 
+    HDFS-4127. Log message is not correct in case of short of replica.
+    (Junping Du via suresh)
+
 Release 2.0.2-alpha - 2012-09-07 
 
   INCOMPATIBLE CHANGES

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

@@ -185,7 +185,7 @@ private DatanodeDescriptor chooseTarget(int numOfReplicas,
     if (numOfReplicas == 0 || clusterMap.getNumOfLeaves()==0) {
       return writer;
     }
-    int totalReplicasExpected = numOfReplicas;
+    int totalReplicasExpected = numOfReplicas + results.size();
       
     int numOfResults = results.size();
     boolean newBlock = (numOfResults==0);
@@ -231,7 +231,8 @@ private DatanodeDescriptor chooseTarget(int numOfReplicas,
           maxNodesPerRack, results, avoidStaleNodes);
     } catch (NotEnoughReplicasException e) {
       LOG.warn("Not able to place enough replicas, still in need of "
-               + numOfReplicas + " to reach " + totalReplicasExpected + "\n"
+               + (totalReplicasExpected - results.size()) + " to reach "
+               + totalReplicasExpected + "\n"
                + e.getMessage());
       if (avoidStaleNodes) {
         // ecxludedNodes now has - initial excludedNodes, any nodes that were

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicy.java

@@ -19,6 +19,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
@@ -44,6 +45,10 @@
 import org.apache.hadoop.net.NetworkTopology;
 import org.apache.hadoop.net.Node;
 import org.apache.hadoop.util.Time;
+import org.apache.log4j.AppenderSkeleton;
+import org.apache.log4j.Level;
+import org.apache.log4j.Logger;
+import org.apache.log4j.spi.LoggingEvent;
 import org.junit.BeforeClass;
 import org.junit.Rule;
 import org.junit.Test;
@@ -375,7 +380,71 @@ public void testChooseTarget5() throws Exception {
         new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
     assertEquals(targets.length, 3);
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]));
-    assertFalse(cluster.isOnSameRack(targets[0], targets[1]));    
+    assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
+  }
+  
+  /**
+   * In this testcase, it tries to choose more targets than available nodes and
+   * check the result. 
+   * @throws Exception
+   */
+  @Test
+  public void testChooseTargetWithMoreThanAvaiableNodes() throws Exception {
+    // make data node 0 & 1 to be not qualified to choose: not enough disk space
+    for(int i=0; i<2; i++) {
+      dataNodes[i].updateHeartbeat(
+          2*HdfsConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L,
+          (HdfsConstants.MIN_BLOCKS_FOR_WRITE-1)*BLOCK_SIZE, 0L, 0, 0);
+    }
+    
+    final TestAppender appender = new TestAppender();
+    final Logger logger = Logger.getRootLogger();
+    logger.addAppender(appender);
+    
+    // try to choose NUM_OF_DATANODES which is more than actually available
+    // nodes.
+    DatanodeDescriptor[] targets = replicator.chooseTarget(filename, 
+        NUM_OF_DATANODES, dataNodes[0], new ArrayList<DatanodeDescriptor>(),
+        BLOCK_SIZE);
+    assertEquals(targets.length, NUM_OF_DATANODES - 2);
+
+    final List<LoggingEvent> log = appender.getLog();
+    assertNotNull(log);
+    assertFalse(log.size() == 0);
+    final LoggingEvent lastLogEntry = log.get(log.size() - 1);
+    
+    assertEquals(lastLogEntry.getLevel(), Level.WARN);
+    // Suppose to place replicas on each node but two data nodes are not
+    // available for placing replica, so here we expect a short of 2
+    assertTrue(((String)lastLogEntry.getMessage()).contains("in need of 2"));
+    
+    for(int i=0; i<2; i++) {
+      dataNodes[i].updateHeartbeat(
+          2*HdfsConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L,
+          HdfsConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L, 0, 0);
+    }
+  }
+  
+  class TestAppender extends AppenderSkeleton {
+    private final List<LoggingEvent> log = new ArrayList<LoggingEvent>();
+
+    @Override
+    public boolean requiresLayout() {
+      return false;
+    }
+
+    @Override
+    protected void append(final LoggingEvent loggingEvent) {
+      log.add(loggingEvent);
+    }
+
+    @Override
+    public void close() {
+    }
+
+    public List<LoggingEvent> getLog() {
+      return new ArrayList<LoggingEvent>(log);
+    }
   }
 
   private boolean containsWithinRange(DatanodeDescriptor target,