Package org.apache.hadoop.hdfs.server.protocol

Interface NamenodeProtocol

All Known Subinterfaces:
BalancerProtocols, NamenodeProtocols
All Known Implementing Classes:
NamenodeProtocolTranslatorPB, NameNodeRpcServer
@Private public interface NamenodeProtocol
Protocol that a secondary NameNode uses to communicate with the NameNode. Also used by external storage policy satisfier. It's used to get part of the name node state

  • Field Details

    • versionID

      static final long versionID
      Until version 6L, this class served as both the client interface to the NN AND the RPC protocol used to communicate with the NN. This class is used by both the DFSClient and the NN server side to insulate from the protocol serialization. If you are adding/changing NN's interface then you need to change both this class and ALSO related protocol buffer wire protocol definition in NamenodeProtocol.proto. For more details on protocol buffer wire protocol, please see .../org/apache/hadoop/hdfs/protocolPB/overview.html 6: Switch to txid-based file naming for image and edits
      See Also:

    • NOTIFY

      static final int NOTIFY
      See Also:

    • FATAL

      static final int FATAL
      See Also:

    • ACT_UNKNOWN

      static final int ACT_UNKNOWN
      See Also:

    • ACT_SHUTDOWN

      static final int ACT_SHUTDOWN
      See Also:

    • ACT_CHECKPOINT

      static final int ACT_CHECKPOINT
      See Also:

  • Method Details

    • getBlocks

      BlocksWithLocations getBlocks(org.apache.hadoop.hdfs.protocol.DatanodeInfo datanode, long size, long minBlockSize, long hotBlockTimeInterval, org.apache.hadoop.fs.StorageType storageType) throws IOException
      Get a list of blocks belonging to datanode whose total size equals size.
      Parameters:
      datanode - a data node
      size - requested size
      minBlockSize - each block should be of this minimum Block Size
      hotBlockTimeInterval - prefer to get blocks which are belong to the cold files accessed before the time interval
      storageType - the given storage type StorageType
      Returns:
      BlocksWithLocations a list of blocks & their locations
      Throws:
      IOException - if size is less than or equal to 0 or datanode does not exist
      See Also:

    • getBlockKeys

      ExportedBlockKeys getBlockKeys() throws IOException
      Get the current block keys
      Returns:
      ExportedBlockKeys containing current block keys
      Throws:
      IOException

    • getTransactionID

      long getTransactionID() throws IOException
      Returns:
      The most recent transaction ID that has been synced to persistent storage, or applied from persistent storage in the case of a non-active node.
      Throws:
      IOException

    • getMostRecentCheckpointTxId

      long getMostRecentCheckpointTxId() throws IOException
      Get the transaction ID of the most recent checkpoint.
      Throws:
      IOException

    • getMostRecentNameNodeFileTxId

      long getMostRecentNameNodeFileTxId(NNStorage.NameNodeFile nnf) throws IOException
      Get the transaction ID of the most recent checkpoint for the given NameNodeFile.
      Throws:
      IOException

    • rollEditLog

      CheckpointSignature rollEditLog() throws IOException
      Closes the current edit log and opens a new one. The call fails if the file system is in SafeMode.
      Returns:
      a unique token to identify this transaction.
      Throws:
      IOException

    • versionRequest

      NamespaceInfo versionRequest() throws IOException
      Request name-node version and storage information.
      Returns:
      NamespaceInfo identifying versions and storage information of the name-node
      Throws:
      IOException

    • errorReport

      void errorReport(NamenodeRegistration registration, int errorCode, String msg) throws IOException
      Report to the active name-node an error occurred on a subordinate node. Depending on the error code the active node may decide to unregister the reporting node.
      Parameters:
      registration - requesting node.
      errorCode - indicates the error
      msg - free text description of the error
      Throws:
      IOException

    • registerSubordinateNamenode

      NamenodeRegistration registerSubordinateNamenode(NamenodeRegistration registration) throws IOException
      Register a subordinate name-node like backup node.
      Returns:
      NamenodeRegistration of the node, which this node has just registered with.
      Throws:
      IOException

    • startCheckpoint

      NamenodeCommand startCheckpoint(NamenodeRegistration registration) throws IOException
      A request to the active name-node to start a checkpoint. The name-node should decide whether to admit it or reject. The name-node also decides what should be done with the backup node image before and after the checkpoint.
      Parameters:
      registration - the requesting node
      Returns:
      CheckpointCommand if checkpoint is allowed.
      Throws:
      IOException
      See Also:

    • endCheckpoint

      void endCheckpoint(NamenodeRegistration registration, CheckpointSignature sig) throws IOException
      A request to the active name-node to finalize previously started checkpoint.
      Parameters:
      registration - the requesting node
      sig - CheckpointSignature which identifies the checkpoint.
      Throws:
      IOException

    • getEditLogManifest

      RemoteEditLogManifest getEditLogManifest(long sinceTxId) throws IOException
      Return a structure containing details about all edit logs available to be fetched from the NameNode.
      Parameters:
      sinceTxId - return only logs that contain transactions >= sinceTxId
      Throws:
      IOException

    • isUpgradeFinalized

      boolean isUpgradeFinalized() throws IOException
      Returns:
      Whether the NameNode is in upgrade state (false) or not (true)
      Throws:
      IOException

    • isRollingUpgrade

      boolean isRollingUpgrade() throws IOException
      return whether the Namenode is rolling upgrade in progress (true) or not (false).
      Returns:
      Throws:
      IOException

    • getNextSPSPath

      Long getNextSPSPath() throws IOException
      Returns:
      Gets the next available sps path, otherwise null. This API used by External SPS.
      Throws:
      IOException