HDFS-5480. Update Balancer for HDFS-2832. (Contributed by szetszwo)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2832@1540547 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES_HDFS-2832.txt

@@ -91,3 +91,5 @@ IMPROVEMENTS:
     HDFS-5481. Fix TestDataNodeVolumeFailure in branch HDFS-2832. (Contributed
     by Junping Du)
 
+    HDFS-5480. Update Balancer for HDFS-2832. (Contributed by szetszwo)
+

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/DatanodeProtocolServerSideTranslatorPB.java

@@ -42,7 +42,6 @@ import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.ReportBadBlo
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.ReportBadBlocksResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.StorageBlockReportProto;
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.StorageReceivedDeletedBlocksProto;
-import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.StorageReportProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.DatanodeIDProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.LocatedBlockProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.VersionRequestProto;
@@ -57,7 +56,6 @@ import org.apache.hadoop.hdfs.server.protocol.StorageBlockReport;
 import org.apache.hadoop.hdfs.server.protocol.StorageReceivedDeletedBlocks;
 import org.apache.hadoop.hdfs.server.protocol.StorageReport;
 
-import com.google.common.primitives.Longs;
 import com.google.protobuf.RpcController;
 import com.google.protobuf.ServiceException;
 
@@ -103,14 +101,8 @@ public class DatanodeProtocolServerSideTranslatorPB implements
       HeartbeatRequestProto request) throws ServiceException {
     HeartbeatResponse response;
     try {
-      List<StorageReportProto> list = request.getReportsList();
+      final StorageReport[] report = PBHelper.convertStorageReports(
-      StorageReport[] report = new StorageReport[list.size()];
+          request.getReportsList());
-      int i = 0;
-      for (StorageReportProto p : list) {
-        report[i++] = new StorageReport(p.getStorageUuid(), p.getFailed(),
-            p.getCapacity(), p.getDfsUsed(), p.getRemaining(),
-            p.getBlockPoolUsed());
-      }
       response = impl.sendHeartbeat(PBHelper.convert(request.getRegistration()),
           report, request.getDnCacheCapacity(), request.getDnCacheUsed(),
           request.getXmitsInProgress(),

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelper.java

@@ -25,41 +25,40 @@ import java.util.Arrays;
 import java.util.EnumSet;
 import java.util.List;
 
-import com.google.common.base.Preconditions;
 import org.apache.hadoop.fs.ContentSummary;
 import org.apache.hadoop.fs.CreateFlag;
 import org.apache.hadoop.fs.FsServerDefaults;
 import org.apache.hadoop.fs.Path;
-import org.apache.hadoop.hdfs.StorageType;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.ha.HAServiceProtocol.HAServiceState;
 import org.apache.hadoop.ha.proto.HAServiceProtocolProtos;
 import org.apache.hadoop.hdfs.DFSUtil;
+import org.apache.hadoop.hdfs.StorageType;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.CorruptFileBlocks;
 import org.apache.hadoop.hdfs.protocol.DatanodeID;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
-import org.apache.hadoop.hdfs.protocol.PathBasedCacheDirective;
-import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo.AdminStates;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
-import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
-import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffType;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.HdfsLocatedFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
+import org.apache.hadoop.hdfs.protocol.PathBasedCacheDirective;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffType;
 import org.apache.hadoop.hdfs.protocol.SnapshottableDirectoryStatus;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.CreateFlagProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.DatanodeReportTypeProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.GetFsStatsResponseProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SafeModeActionProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.PathBasedCacheDirectiveInfoProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SafeModeActionProto;
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.BalancerBandwidthCommandProto;
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.BlockCommandProto;
 import org.apache.hadoop.hdfs.protocol.proto.DatanodeProtocolProtos.BlockIdCommandProto;
@@ -98,8 +97,6 @@ import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.HdfsFileStatusProto.File
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.LocatedBlockProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.LocatedBlockProto.Builder;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.LocatedBlocksProto;
-import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.StorageUuidsProto;
-import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.StorageTypeProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.NamenodeCommandProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.NamenodeRegistrationProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.NamenodeRegistrationProto.NamenodeRoleProto;
@@ -113,6 +110,8 @@ import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.SnapshotDiffReportProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.SnapshottableDirectoryListingProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.SnapshottableDirectoryStatusProto;
 import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.StorageInfoProto;
+import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.StorageTypeProto;
+import org.apache.hadoop.hdfs.protocol.proto.HdfsProtos.StorageUuidsProto;
 import org.apache.hadoop.hdfs.protocol.proto.JournalProtocolProtos.JournalInfoProto;
 import org.apache.hadoop.hdfs.security.token.block.BlockKey;
 import org.apache.hadoop.hdfs.security.token.block.BlockTokenIdentifier;
@@ -288,12 +287,16 @@ public class PBHelper {
   public static BlockWithLocationsProto convert(BlockWithLocations blk) {
     return BlockWithLocationsProto.newBuilder()
         .setBlock(convert(blk.getBlock()))
+        .addAllDatanodeUuids(Arrays.asList(blk.getDatanodeUuids()))
         .addAllStorageUuids(Arrays.asList(blk.getStorageIDs())).build();
   }
 
   public static BlockWithLocations convert(BlockWithLocationsProto b) {
-    return new BlockWithLocations(convert(b.getBlock()), b.getStorageUuidsList()
+    final List<String> datanodeUuids = b.getDatanodeUuidsList();
-        .toArray(new String[0]));
+    final List<String> storageUuids = b.getStorageUuidsList();
+    return new BlockWithLocations(convert(b.getBlock()),
+        datanodeUuids.toArray(new String[datanodeUuids.size()]),
+        storageUuids.toArray(new String[storageUuids.size()]));
   }
 
   public static BlocksWithLocationsProto convert(BlocksWithLocations blks) {
@@ -1535,6 +1538,21 @@ public class PBHelper {
     return builder.build();
   }
 
+  public static StorageReport convert(StorageReportProto p) {
+    return new StorageReport(p.getStorageUuid(), p.getFailed(),
+        p.getCapacity(), p.getDfsUsed(), p.getRemaining(),
+        p.getBlockPoolUsed());
+  }
+
+  public static StorageReport[] convertStorageReports(
+      List<StorageReportProto> list) {
+    final StorageReport[] report = new StorageReport[list.size()];
+    for (int i = 0; i < report.length; i++) {
+      report[i] = convert(list.get(i));
+    }
+    return report;
+  }
+
   public static JournalInfo convert(JournalInfoProto info) {
     int lv = info.hasLayoutVersion() ? info.getLayoutVersion() : 0;
     int nsID = info.hasNamespaceID() ? info.getNamespaceID() : 0;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java

@@ -18,7 +18,6 @@
 package org.apache.hadoop.hdfs.server.balancer;
 
 import static com.google.common.base.Preconditions.checkArgument;
-
 import static org.apache.hadoop.hdfs.protocolPB.PBHelper.vintPrefixed;
 
 import java.io.BufferedInputStream;
@@ -221,8 +220,8 @@ public class Balancer {
   private Map<Block, BalancerBlock> globalBlockList
                  = new HashMap<Block, BalancerBlock>();
   private MovedBlocks movedBlocks = new MovedBlocks();
-  // Map storage IDs to BalancerDatanodes
+  /** Map (datanodeUuid -> BalancerDatanodes) */
-  private Map<String, BalancerDatanode> datanodes
+  private final Map<String, BalancerDatanode> datanodeMap
       = new HashMap<String, BalancerDatanode>();
   
   private NetworkTopology cluster;
@@ -241,6 +240,14 @@ public class Balancer {
     private PendingBlockMove() {
     }
     
+    @Override
+    public String toString() {
+      final Block b = block.getBlock();
+      return b + " with size=" + b.getNumBytes() + " from "
+          + source.getDisplayName() + " to " + target.getDisplayName()
+          + " through " + proxySource.getDisplayName();
+    }
+
     /* choose a block & a proxy source for this pendingMove 
      * whose source & target have already been chosen.
      * 
@@ -272,11 +279,7 @@ public class Balancer {
             if ( chooseProxySource() ) {
               movedBlocks.add(block);
               if (LOG.isDebugEnabled()) {
-                LOG.debug("Decided to move block "+ block.getBlockId()
+                LOG.debug("Decided to move " + this);
-                    +" with a length of "+StringUtils.byteDesc(block.getNumBytes())
-                    + " bytes from " + source.getDisplayName()
-                    + " to " + target.getDisplayName()
-                    + " using proxy source " + proxySource.getDisplayName() );
               }
               return true;
             }
@@ -352,17 +355,9 @@ public class Balancer {
         sendRequest(out);
         receiveResponse(in);
         bytesMoved.inc(block.getNumBytes());
-        LOG.info( "Moving block " + block.getBlock().getBlockId() +
+        LOG.info("Successfully moved " + this);
-              " from "+ source.getDisplayName() + " to " +
-              target.getDisplayName() + " through " +
-              proxySource.getDisplayName() +
-              " is succeeded." );
       } catch (IOException e) {
-        LOG.warn("Error moving block "+block.getBlockId()+
+        LOG.warn("Failed to move " + this + ": " + e.getMessage());
-            " from " + source.getDisplayName() + " to " +
-            target.getDisplayName() + " through " +
-            proxySource.getDisplayName() +
-            ": "+e.getMessage());
       } finally {
         IOUtils.closeStream(out);
         IOUtils.closeStream(in);
@@ -414,9 +409,7 @@ public class Balancer {
         @Override
         public void run() {
           if (LOG.isDebugEnabled()) {
-            LOG.debug("Starting moving "+ block.getBlockId() +
+            LOG.debug("Start moving " + PendingBlockMove.this);
-                " from " + proxySource.getDisplayName() + " to " +
-                target.getDisplayName());
           }
           dispatch();
         }
@@ -463,11 +456,6 @@ public class Balancer {
       return block;
     }
     
-    /* Return the block id */
-    private long getBlockId() {
-      return block.getBlockId();
-    }
-    
     /* Return the length of the block */
     private long getNumBytes() {
       return block.getNumBytes();
@@ -674,10 +662,10 @@ public class Balancer {
         
           synchronized (block) {
             // update locations
-            for ( String storageID : blk.getStorageIDs() ) {
+            for (String datanodeUuid : blk.getDatanodeUuids()) {
-              BalancerDatanode datanode = datanodes.get(storageID);
+              final BalancerDatanode d = datanodeMap.get(datanodeUuid);
               if (datanode != null) { // not an unknown datanode
-                block.addLocation(datanode);
+                block.addLocation(d);
               }
             }
           }
@@ -911,13 +899,13 @@ public class Balancer {
               datanodeS.utilization)*datanodeS.datanode.getCapacity()/100.0);
         }
       }
-      this.datanodes.put(datanode.getDatanodeUuid(), datanodeS);
+      datanodeMap.put(datanode.getDatanodeUuid(), datanodeS);
     }
 
     //logging
     logNodes();
     
-    assert (this.datanodes.size() == 
+    assert (this.datanodeMap.size() == 
       overUtilizedDatanodes.size()+underUtilizedDatanodes.size()+
       aboveAvgUtilizedDatanodes.size()+belowAvgUtilizedDatanodes.size())
       : "Mismatched number of datanodes";
@@ -989,9 +977,9 @@ public class Balancer {
     // At last, match all remaining nodes
     chooseNodes(ANY_OTHER);
     
-    assert (datanodes.size() >= sources.size()+targets.size())
+    assert (datanodeMap.size() >= sources.size()+targets.size())
       : "Mismatched number of datanodes (" +
-      datanodes.size() + " total, " +
+      datanodeMap.size() + " total, " +
       sources.size() + " sources, " +
       targets.size() + " targets)";
 
@@ -1292,7 +1280,7 @@ public class Balancer {
     this.aboveAvgUtilizedDatanodes.clear();
     this.belowAvgUtilizedDatanodes.clear();
     this.underUtilizedDatanodes.clear();
-    this.datanodes.clear();
+    this.datanodeMap.clear();
     this.sources.clear();
     this.targets.clear();  
     this.policy.reset();

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

@@ -694,17 +694,17 @@ public class BlockManager {
   /**
    * Get all valid locations of the block
    */
-  private List<String> getValidLocations(Block block) {
+  private List<DatanodeStorageInfo> getValidLocations(Block block) {
-    ArrayList<String> machineSet =
+    final List<DatanodeStorageInfo> locations
-      new ArrayList<String>(blocksMap.numNodes(block));
+        = new ArrayList<DatanodeStorageInfo>(blocksMap.numNodes(block));
     for(DatanodeStorageInfo storage : blocksMap.getStorages(block)) {
       final String storageID = storage.getStorageID();
       // filter invalidate replicas
       if(!invalidateBlocks.contains(storageID, block)) {
-        machineSet.add(storageID);
+        locations.add(storage);
       }
     }
-    return machineSet;
+    return locations;
   }
   
   private List<LocatedBlock> createLocatedBlockList(final BlockInfo[] blocks,
@@ -2622,12 +2622,18 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
    * return the length of the added block; 0 if the block is not added
    */
   private long addBlock(Block block, List<BlockWithLocations> results) {
-    final List<String> machineSet = getValidLocations(block);
+    final List<DatanodeStorageInfo> locations = getValidLocations(block);
-    if(machineSet.size() == 0) {
+    if(locations.size() == 0) {
       return 0;
     } else {
-      results.add(new BlockWithLocations(block, 
+      final String[] datanodeUuids = new String[locations.size()];
-          machineSet.toArray(new String[machineSet.size()])));
+      final String[] storageIDs = new String[datanodeUuids.length];
+      for(int i = 0; i < locations.size(); i++) {
+        final DatanodeStorageInfo s = locations.get(i);
+        datanodeUuids[i] = s.getDatanodeDescriptor().getDatanodeUuid();
+        storageIDs[i] = s.getStorageID();
+      }
+      results.add(new BlockWithLocations(block, datanodeUuids, storageIDs));
       return block.getNumBytes();
     }
   }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataXceiver.java

@@ -866,7 +866,8 @@ class DataXceiver extends Receiver implements Runnable {
       datanode.notifyNamenodeReceivedBlock(
           block, delHint, blockReceiver.getReplicaInfo().getStorageUuid());
 
-      LOG.info("Moved " + block + " from " + peer.getRemoteAddressString());
+      LOG.info("Moved " + block + " from " + peer.getRemoteAddressString()
+          + ", delHint=" + delHint);
       
     } catch (IOException ioe) {
       opStatus = ERROR;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/protocol/BlocksWithLocations.java

@@ -17,6 +17,8 @@
  */
 package org.apache.hadoop.hdfs.server.protocol;
 
+import java.util.Arrays;
+
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.hdfs.protocol.Block;
@@ -34,12 +36,14 @@ public class BlocksWithLocations {
   @InterfaceAudience.Private
   @InterfaceStability.Evolving
   public static class BlockWithLocations {
-    Block block;
+    final Block block;
-    String storageIDs[];
+    final String[] datanodeUuids;
+    final String[] storageIDs;
     
     /** constructor */
-    public BlockWithLocations(Block block, String[] storageIDs) {
+    public BlockWithLocations(Block block, String[] datanodeUuids, String[] storageIDs) {
       this.block = block;
+      this.datanodeUuids = datanodeUuids;
       this.storageIDs = storageIDs;
     }
     
@@ -48,10 +52,30 @@ public class BlocksWithLocations {
       return block;
     }
     
-    /** get the block's locations */
+    /** get the block's datanode locations */
+    public String[] getDatanodeUuids() {
+      return datanodeUuids;
+    }
+
+    /** get the block's storage locations */
     public String[] getStorageIDs() {
       return storageIDs;
     }
+    
+    @Override
+    public String toString() {
+      final StringBuilder b = new StringBuilder();
+      b.append(block);
+      if (datanodeUuids.length == 0) {
+        return b.append("[]").toString();
+      }
+      
+      b.append(storageIDs[0]).append('@').append(datanodeUuids[0]);
+      for(int i = 1; i < datanodeUuids.length; i++) {
+        b.append(", ").append(storageIDs[i]).append("@").append(datanodeUuids[i]);
+      }
+      return b.append("]").toString();
+    }
   }
 
   private BlockWithLocations[] blocks;

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/hdfs.proto

@@ -355,7 +355,8 @@ message BlockProto {
  */
 message BlockWithLocationsProto {
   required BlockProto block = 1;   // Block
-  repeated string storageUuids = 2;  // Datanodes with replicas of the block
+  repeated string datanodeUuids = 2; // Datanodes with replicas of the block
+  repeated string storageUuids = 3;  // Storages with replicas of the block
 }
 
 /**

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSCluster.java

@@ -328,9 +328,10 @@ public class MiniDFSCluster {
           builder.nameNodePort, builder.nameNodeHttpPort);
     }
     
-    LOG.info("starting cluster with " + 
+    final int numNameNodes = builder.nnTopology.countNameNodes();
-        builder.nnTopology.countNameNodes() + " namenodes.");
+    LOG.info("starting cluster: numNameNodes=" + numNameNodes
-    nameNodes = new NameNodeInfo[builder.nnTopology.countNameNodes()];
+        + ", numDataNodes=" + builder.numDataNodes);
+    nameNodes = new NameNodeInfo[numNameNodes];
       
     initMiniDFSCluster(builder.conf,
                        builder.numDataNodes,
@@ -1920,12 +1921,14 @@ public class MiniDFSCluster {
     
     // Wait for expected number of datanodes to start
     if (dnInfo.length != numDataNodes) {
+      LOG.info("dnInfo.length != numDataNodes");
       return true;
     }
     
     // if one of the data nodes is not fully started, continue to wait
     for (DataNodeProperties dn : dataNodes) {
       if (!dn.datanode.isDatanodeFullyStarted()) {
+        LOG.info("!dn.datanode.isDatanodeFullyStarted()");
         return true;
       }
     }
@@ -1934,6 +1937,7 @@ public class MiniDFSCluster {
     // using (capacity == 0) as proxy.
     for (DatanodeInfo dn : dnInfo) {
       if (dn.getCapacity() == 0) {
+        LOG.info("dn.getCapacity() == 0");
         return true;
       }
     }
@@ -1941,6 +1945,7 @@ public class MiniDFSCluster {
     // If datanode dataset is not initialized then wait
     for (DataNodeProperties dn : dataNodes) {
       if (DataNodeTestUtils.getFSDataset(dn.datanode) == null) {
+        LOG.info("DataNodeTestUtils.getFSDataset(dn.datanode) == null");
         return true;
       }
     }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/protocolPB/TestPBHelper.java

@@ -166,8 +166,10 @@ public class TestPBHelper {
   }
 
   private static BlockWithLocations getBlockWithLocations(int bid) {
-    return new BlockWithLocations(new Block(bid, 0, 1), new String[] { "dn1",
+    final String[] datanodeUuids = {"dn1", "dn2", "dn3"};
-        "dn2", "dn3" });
+    final String[] storageIDs = {"s1", "s2", "s3"};
+    return new BlockWithLocations(new Block(bid, 0, 1),
+        datanodeUuids, storageIDs);
   }
 
   private void compare(BlockWithLocations locs1, BlockWithLocations locs2) {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancer.java

@@ -31,6 +31,7 @@ import java.util.concurrent.TimeoutException;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.apache.commons.logging.impl.Log4JLogger;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
@@ -50,6 +51,7 @@ import org.apache.hadoop.hdfs.server.balancer.Balancer.Cli;
 import org.apache.hadoop.hdfs.server.datanode.SimulatedFSDataset;
 import org.apache.hadoop.util.Time;
 import org.apache.hadoop.util.Tool;
+import org.apache.log4j.Level;
 import org.junit.Test;
 
 /**
@@ -58,6 +60,9 @@ import org.junit.Test;
 public class TestBalancer {
   private static final Log LOG = LogFactory.getLog(
   "org.apache.hadoop.hdfs.TestBalancer");
+  static {
+    ((Log4JLogger)Balancer.LOG).getLogger().setLevel(Level.ALL);
+  }
 
   final static long CAPACITY = 500L;
   final static String RACK0 = "/rack0";
@@ -292,6 +297,16 @@ public class TestBalancer {
     } while (!balanced);
   }
 
+  String long2String(long[] array) {
+    if (array.length == 0) {
+      return "<empty>";
+    }
+    StringBuilder b = new StringBuilder("[").append(array[0]);
+    for(int i = 1; i < array.length; i++) {
+      b.append(", ").append(array[i]);
+    }
+    return b.append("]").toString();
+  }
   /** This test start a cluster with specified number of nodes, 
    * and fills it to be 30% full (with a single file replicated identically
    * to all datanodes);
@@ -308,6 +323,11 @@ public class TestBalancer {
    */
   private void doTest(Configuration conf, long[] capacities, String[] racks, 
       long newCapacity, String newRack, boolean useTool) throws Exception {
+    LOG.info("capacities = " +  long2String(capacities)); 
+    LOG.info("racks      = " +  Arrays.asList(racks)); 
+    LOG.info("newCapacity= " +  newCapacity); 
+    LOG.info("newRack    = " +  newRack); 
+    LOG.info("useTool    = " +  useTool); 
     assertEquals(capacities.length, racks.length);
     int numOfDatanodes = capacities.length;
     cluster = new MiniDFSCluster.Builder(conf)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/SimulatedFSDataset.java

@@ -21,7 +21,11 @@ import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
 
 import javax.management.NotCompliantMBeanException;
 import javax.management.ObjectName;
@@ -43,6 +47,7 @@ import org.apache.hadoop.hdfs.server.datanode.fsdataset.ReplicaOutputStreams;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.RollingLogs;
 import org.apache.hadoop.hdfs.server.datanode.metrics.FSDatasetMBean;
 import org.apache.hadoop.hdfs.server.protocol.BlockRecoveryCommand.RecoveringBlock;
+import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
 import org.apache.hadoop.hdfs.server.protocol.ReplicaRecoveryInfo;
 import org.apache.hadoop.hdfs.server.protocol.StorageReport;
 import org.apache.hadoop.io.IOUtils;
@@ -319,15 +324,15 @@ public class SimulatedFSDataset implements FsDatasetSpi<FsVolumeSpi> {
   private static class SimulatedStorage {
     private Map<String, SimulatedBPStorage> map = 
       new HashMap<String, SimulatedBPStorage>();
-    private final String storageUuid = "SimulatedStorage-UUID";
+    private final String storageUuid = "SimulatedStroage-" + DatanodeStorage.newStorageID();
 
-    private long capacity;  // in bytes
+    private final long capacity;  // in bytes
     
     synchronized long getFree() {
       return capacity - getUsed();
     }
     
-    synchronized long getCapacity() {
+    long getCapacity() {
       return capacity;
     }
     
@@ -383,9 +388,14 @@ public class SimulatedFSDataset implements FsDatasetSpi<FsVolumeSpi> {
       return bpStorage;
     }
 
-    public String getStorageUuid() {
+    String getStorageUuid() {
       return storageUuid;
     }
+
+    synchronized StorageReport getStorageReport(String bpid) {
+      return new StorageReport(getStorageUuid(), false, getCapacity(),
+          getUsed(), getFree(), map.get(bpid).getUsed());
+    }
   }
   
   private final Map<String, Map<Block, BInfo>> blockMap
@@ -400,8 +410,9 @@ public class SimulatedFSDataset implements FsDatasetSpi<FsVolumeSpi> {
       }
       this.datanodeUuid = storage.getDatanodeUuid();
     } else {
-      this.datanodeUuid = "unknownStorageId-" + UUID.randomUUID();
+      this.datanodeUuid = "SimulatedDatanode-" + DataNode.generateUuid();
     }
+
     registerMBean(datanodeUuid);
     this.storage = new SimulatedStorage(
         conf.getLong(CONFIG_PROPERTY_CAPACITY, DEFAULT_CAPACITY));
@@ -478,7 +489,7 @@ public class SimulatedFSDataset implements FsDatasetSpi<FsVolumeSpi> {
       String bpid) {
     Map<String, BlockListAsLongs> reports =
         new HashMap<String, BlockListAsLongs>();
-    reports.put("", getBlockReport(bpid));
+    reports.put(storage.storageUuid, getBlockReport(bpid));
     return reports;
   }
 
@@ -1029,7 +1040,7 @@ public class SimulatedFSDataset implements FsDatasetSpi<FsVolumeSpi> {
 
   @Override
   public StorageReport[] getStorageReports(String bpid) {
-    return new StorageReport[0];
+    return new StorageReport[] {storage.getStorageReport(bpid)};
   }
 
   @Override