Package org.apache.hadoop.hdfs.tools

Class DFSAdmin

java.lang.Object
org.apache.hadoop.conf.Configured
org.apache.hadoop.fs.FsShell
org.apache.hadoop.hdfs.tools.DFSAdmin
All Implemented Interfaces:
org.apache.hadoop.conf.Configurable, org.apache.hadoop.util.Tool
@Private public class DFSAdmin extends org.apache.hadoop.fs.FsShell
This class provides some DFS administrative access shell commands.

  • Nested Class Summary

    Nested classes/interfaces inherited from class org.apache.hadoop.fs.FsShell

    org.apache.hadoop.fs.FsShell.Help, org.apache.hadoop.fs.FsShell.Usage

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String[]
    DFS_REPORT_ARGS
     

    Fields inherited from class org.apache.hadoop.fs.FsShell

    commandFactory

  • Constructor Summary

    Constructors
    Constructor
    Description
    DFSAdmin()
    Construct a DFSAdmin object.
    DFSAdmin(org.apache.hadoop.conf.Configuration conf)
    Construct a DFSAdmin object.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    allowSnapshot(String[] argv)
    Allow snapshot on a directory.
    void
    disallowSnapshot(String[] argv)
    Disallow snapshot on a directory.
    int
    fetchImage(String[] argv, int idx)
    Download the most recent fsimage from the name node, and save it to a local file in the given directory.
    int
    finalizeUpgrade()
    Command to ask the namenode to finalize previously performed upgrade.
    int
    genericRefresh(String[] argv, int i)
     
    int
    getBalancerBandwidth(String[] argv, int idx)
    Command to get balancer bandwidth for the given datanode.
    protected org.apache.hadoop.hdfs.DistributedFileSystem
    getDFS()
     
    int
    getUpgradeStatus()
    Command to get the upgrade status of each namenode in the nameservice.
    int
    listOpenFiles(String[] argv)
    Command to list all the open files currently managed by NameNode.
    static void
    main(String[] argv)
    main() has some simple utility methods.
    int
    metaSave(String[] argv, int idx)
    Dumps DFS data structures into specified file.
    int
    printTopology()
    Display each rack and the nodes assigned to that rack, as determined by the NameNode, in a hierarchical manner.
    void
    provisionSnapshotTrash(String[] argv)
    Provision trash root in a snapshottable directory.
    int
    reconfig(String[] argv, int i)
     
    int
    refreshCallQueue()
     
    int
    refreshNodes()
    Command to ask the namenode to reread the hosts and excluded hosts file.
    int
    refreshServiceAcl()
    Refresh the authorization policy on the NameNode.
    int
    refreshSuperUserGroupsConfiguration()
    refreshSuperUserGroupsConfiguration NameNode.
    int
    refreshUserToGroupsMappings()
    Refresh the user-to-groups mappings on the NameNode.
    void
    report(String[] argv, int i)
    Gives a report on how the FileSystem is doing.
    int
    restoreFailedStorage(String arg)
    Command to enable/disable/check restoring of failed storage replicas in the namenode.
    int
    rollEdits()
     
    int
    run(String[] argv)
     
    int
    saveNamespace(String[] argv)
    Command to ask the namenode to save the namespace.
    int
    setBalancerBandwidth(String[] argv, int idx)
    Command to ask the active namenode to set the balancer bandwidth.
    void
    setSafeMode(String[] argv, int idx)
    Safe mode maintenance command.
    int
    triggerBlockReport(String[] argv)
     
    int
    upgrade(String arg)
    Upgrade command to get the status of upgrade or ask NameNode to finalize the previously performed upgrade.

    Methods inherited from class org.apache.hadoop.fs.FsShell

    close, getCurrentTrashDir, getCurrentTrashDir, getFS, getHelp, getTrash, getUsagePrefix, init, newShellInstance, registerCommands

    Methods inherited from class org.apache.hadoop.conf.Configured

    getConf, setConf

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    Methods inherited from interface org.apache.hadoop.conf.Configurable

    getConf, setConf

  • Field Details

    • DFS_REPORT_ARGS

      public static final String[] DFS_REPORT_ARGS

  • Constructor Details

    • DFSAdmin

      public DFSAdmin()
      Construct a DFSAdmin object.

    • DFSAdmin

      public DFSAdmin(org.apache.hadoop.conf.Configuration conf)
      Construct a DFSAdmin object.

  • Method Details

    • getDFS

      protected org.apache.hadoop.hdfs.DistributedFileSystem getDFS() throws IOException
      Throws:
      IOException

    • report

      public void report(String[] argv, int i) throws IOException
      Gives a report on how the FileSystem is doing.
      Throws:
      IOException - if the filesystem does not exist.

    • setSafeMode

      public void setSafeMode(String[] argv, int idx) throws IOException
      Safe mode maintenance command. Usage: hdfs dfsadmin -safemode [enter | leave | get | wait | forceExit]
      Parameters:
      argv - List of of command line parameters.
      idx - The index of the command that is being processed.
      Throws:
      IOException - if the filesystem does not exist.

    • triggerBlockReport

      public int triggerBlockReport(String[] argv) throws IOException
      Throws:
      IOException

    • allowSnapshot

      public void allowSnapshot(String[] argv) throws IOException
      Allow snapshot on a directory. Usage: hdfs dfsadmin -allowSnapshot snapshotDir
      Parameters:
      argv - List of of command line parameters.
      Throws:
      IOException

    • disallowSnapshot

      public void disallowSnapshot(String[] argv) throws IOException
      Disallow snapshot on a directory. Usage: hdfs dfsadmin -disallowSnapshot snapshotDir
      Parameters:
      argv - List of of command line parameters.
      Throws:
      IOException

    • provisionSnapshotTrash

      public void provisionSnapshotTrash(String[] argv) throws IOException
      Provision trash root in a snapshottable directory. Usage: hdfs dfsadmin -provisionSnapshotTrash snapshotDir hdfs dfsadmin -provisionSnapshotTrash -all
      Parameters:
      argv - List of of command line parameters.
      Throws:
      IOException

    • saveNamespace

      public int saveNamespace(String[] argv) throws IOException
      Command to ask the namenode to save the namespace. Usage: hdfs dfsadmin -saveNamespace
      Throws:
      IOException
      See Also:
      • ClientProtocol.saveNamespace(long, long)

    • rollEdits

      public int rollEdits() throws IOException
      Throws:
      IOException

    • restoreFailedStorage

      public int restoreFailedStorage(String arg) throws IOException
      Command to enable/disable/check restoring of failed storage replicas in the namenode. Usage: hdfs dfsadmin -restoreFailedStorage true|false|check
      Throws:
      IOException
      See Also:
      • ClientProtocol.restoreFailedStorage(String arg)

    • refreshNodes

      public int refreshNodes() throws IOException
      Command to ask the namenode to reread the hosts and excluded hosts file. Usage: hdfs dfsadmin -refreshNodes
      Throws:
      IOException

    • listOpenFiles

      public int listOpenFiles(String[] argv) throws IOException
      Command to list all the open files currently managed by NameNode. Usage: hdfs dfsadmin -listOpenFiles
      Parameters:
      argv -
      Throws:
      IOException

    • setBalancerBandwidth

      public int setBalancerBandwidth(String[] argv, int idx) throws IOException
      Command to ask the active namenode to set the balancer bandwidth. Usage: hdfs dfsadmin -setBalancerBandwidth bandwidth
      Parameters:
      argv - List of of command line parameters.
      idx - The index of the command that is being processed.
      Throws:
      IOException

    • getBalancerBandwidth

      public int getBalancerBandwidth(String[] argv, int idx) throws IOException
      Command to get balancer bandwidth for the given datanode. Usage: hdfs dfsadmin -getBalancerBandwidth <datanode_host:ipc_port>
      Parameters:
      argv - List of of command line parameters.
      idx - The index of the command that is being processed.
      Throws:
      IOException

    • fetchImage

      public int fetchImage(String[] argv, int idx) throws IOException
      Download the most recent fsimage from the name node, and save it to a local file in the given directory.
      Parameters:
      argv - List of of command line parameters.
      idx - The index of the command that is being processed.
      Returns:
      an exit code indicating success or failure.
      Throws:
      IOException

    • finalizeUpgrade

      public int finalizeUpgrade() throws IOException
      Command to ask the namenode to finalize previously performed upgrade. Usage: hdfs dfsadmin -finalizeUpgrade
      Throws:
      IOException

    • getUpgradeStatus

      public int getUpgradeStatus() throws IOException
      Command to get the upgrade status of each namenode in the nameservice. Usage: hdfs dfsadmin -upgrade query
      Throws:
      IOException

    • upgrade

      public int upgrade(String arg) throws IOException
      Upgrade command to get the status of upgrade or ask NameNode to finalize the previously performed upgrade. Usage: hdfs dfsadmin -upgrade [query | finalize]
      Throws:
      IOException

    • metaSave

      public int metaSave(String[] argv, int idx) throws IOException
      Dumps DFS data structures into specified file. Usage: hdfs dfsadmin -metasave filename
      Parameters:
      argv - List of of command line parameters.
      idx - The index of the command that is being processed.
      Throws:
      IOException - if an error occurred while accessing the file or path.

    • printTopology

      public int printTopology() throws IOException
      Display each rack and the nodes assigned to that rack, as determined by the NameNode, in a hierarchical manner. The nodes and racks are sorted alphabetically.
      Throws:
      IOException - If an error while getting datanode report

    • refreshServiceAcl

      public int refreshServiceAcl() throws IOException
      Refresh the authorization policy on the NameNode.
      Returns:
      exitcode 0 on success, non-zero on failure
      Throws:
      IOException

    • refreshUserToGroupsMappings

      public int refreshUserToGroupsMappings() throws IOException
      Refresh the user-to-groups mappings on the NameNode.
      Returns:
      exitcode 0 on success, non-zero on failure
      Throws:
      IOException

    • refreshSuperUserGroupsConfiguration

      public int refreshSuperUserGroupsConfiguration() throws IOException
      refreshSuperUserGroupsConfiguration NameNode.
      Returns:
      exitcode 0 on success, non-zero on failure
      Throws:
      IOException

    • refreshCallQueue

      public int refreshCallQueue() throws IOException
      Throws:
      IOException

    • reconfig

      public int reconfig(String[] argv, int i) throws IOException, InterruptedException
      Throws:
      IOException
      InterruptedException

    • genericRefresh

      public int genericRefresh(String[] argv, int i) throws IOException
      Throws:
      IOException

    • run

      public int run(String[] argv)
      Specified by:
      run in interface org.apache.hadoop.util.Tool
      Overrides:
      run in class org.apache.hadoop.fs.FsShell
      Parameters:
      argv - The parameters passed to this program.
      Returns:
      0 on success, non zero on error.

    • main

      public static void main(String[] argv) throws Exception
      main() has some simple utility methods.
      Parameters:
      argv - Command line parameters.
      Throws:
      Exception - if the filesystem does not exist.