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:

Configurable, Tool

@InterfaceAudience.Private
public class DFSAdmin
extends FsShell

This class provides some DFS administrative access shell commands.

Nested Class Summary

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

FsShell.Help, FsShell.Usage

Field Summary

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

commandFactory

Constructor Summary

Constructors

Constructor and Description
DFSAdmin() Construct a DFSAdmin object.
DFSAdmin(Configuration conf) Construct a DFSAdmin object.

Method Summary

Methods

Modifier and Type	Method and Description
void	allowSnapshot(String[] argv) Allow snapshot on a directory.
void	disallowSnapshot(String[] argv) Allow 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.
protected DistributedFileSystem	getDFS()
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.
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() Gives a report on how the FileSystem is doing.
int	restoreFaileStorage(String arg) Command to enable/disable/check restoring of failed storage replicas in the namenode.
int	rollEdits()
int	run(String[] argv) run
int	saveNamespace() Command to ask the namenode to save the namespace.
int	setBalancerBandwidth(String[] argv, int idx) Command to ask the namenode to set the balancer bandwidth for all of the datanodes.
void	setSafeMode(String[] argv, int idx) Safe mode maintenance command.

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

close, getCurrentTrashDir, getFS, getTrash, 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

Constructor Detail

DFSAdmin

public DFSAdmin()

Construct a DFSAdmin object.

DFSAdmin

public DFSAdmin(Configuration conf)

Construct a DFSAdmin object.

Method Detail

getDFS

protected DistributedFileSystem getDFS()
                                throws IOException

Throws:

IOException

report

public void report()
            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: java DFSAdmin -safemode [enter | leave | get]

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.

allowSnapshot

public void allowSnapshot(String[] argv)
                   throws IOException

Allow snapshot on a directory. Usage: java DFSAdmin -allowSnapshot snapshotDir

Parameters:

argv - List of of command line parameters.

Throws:

IOException

disallowSnapshot

public void disallowSnapshot(String[] argv)
                      throws IOException

Allow snapshot on a directory. Usage: java DFSAdmin -disallowSnapshot snapshotDir

Parameters:

argv - List of of command line parameters.

Throws:

IOException

saveNamespace

public int saveNamespace()
                  throws IOException

Command to ask the namenode to save the namespace. Usage: java DFSAdmin -saveNamespace

Throws:

IOException

See Also:

ClientProtocol.saveNamespace()

rollEdits

public int rollEdits()
              throws IOException

Throws:

IOException

restoreFaileStorage

public int restoreFaileStorage(String arg)
                        throws IOException

Command to enable/disable/check restoring of failed storage replicas in the namenode. Usage: java 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: java DFSAdmin -refreshNodes

Throws:

IOException

setBalancerBandwidth

public int setBalancerBandwidth(String[] argv,
                       int idx)
                         throws IOException

Command to ask the namenode to set the balancer bandwidth for all of the datanodes. Usage: java DFSAdmin -setBalancerBandwidth bandwidth

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: java DFSAdmin -finalizeUpgrade

Throws:

IOException

metaSave

public int metaSave(String[] argv,
           int idx)
             throws IOException

Dumps DFS data structures into specified file. Usage: java 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

run

public int run(String[] argv)
        throws Exception

Description copied from class: FsShell

run

Specified by:

run in interface Tool

Overrides:

run in class FsShell

Parameters:

argv - The parameters passed to this program.

Returns:

0 on success, non zero on error.

Throws:

Exception - if the filesystem does not exist.

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.