Question

我的目标是让我自己设置HDFS的副本块的位置节点。看了HDFS的代码后，我在这里找到了通话轨道（hadoop 2.2版本）

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我发现BlockManager.java有一个BlockManager.getDatanodeDescriptors(List<String>) line: 1400 BlockManager.chooseTarget(String, int, DatanodeDescriptor, HashMap<Node,Node>, long, List<String>) line: 1378 FSNamesystem.getAdditionalBlock(String, long, String, ExtendedBlock, HashMap<Node,Node>, List<String>) line: 2477 NameNodeRpcServer.addBlock(String, String, ExtendedBlock, DatanodeInfo[], long, String[]) line: 555 ClientNamenodeProtocolServerSideTranslatorPB.addBlock(RpcController, ClientNamenodeProtocolProtos$AddBlockRequestProto) line: 387 ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(Descriptors$MethodDescriptor, RpcController, Message) line: 59582 ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(RPC$Server, String, Writable, long) line: 585 ProtobufRpcEngine$Server(RPC$Server).call(RPC$RpcKind, String, Writable, long) line: 928方法：

chooseTarget

我想如果我可以设置public DatanodeDescriptor[] chooseTarget(final String src, final int numOfReplicas, final DatanodeDescriptor client, final HashMap<Node, Node> excludedNodes, final long blocksize, List<String> favoredNodes) throws IOException {的值，那么我的目标就可以实现。

Answer 1

我从DistributedFileSystem.java（hadoop 2.2版本）中找到了API

  /**
   * Same as  
   * {@link #create(Path, FsPermission, boolean, int, short, long, 
   * Progressable)} with the addition of favoredNodes that is a hint to 
   * where the namenode should place the file blocks.
   * The favored nodes hint is not persisted in HDFS. Hence it may be honored
   * at the creation time only. HDFS could move the blocks during balancing or
   * replication, to move the blocks from favored nodes. A value of null means
   * no favored nodes for this create
   */
  public HdfsDataOutputStream create(final Path f,
      final FsPermission permission, final boolean overwrite,
      final int bufferSize, final short replication, final long blockSize,
      final Progressable progress, final InetSocketAddress[] favoredNodes)
          throws IOException {

如何让我自己设置HDFS的副本块的位置？

1 个答案: