org.apache.hadoop.hdfs.client

Class HdfsAdmin

java.lang.Object

org.apache.hadoop.hdfs.client.HdfsAdmin

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class HdfsAdmin
extends Object

The public API for performing administrative functions on HDFS. Those writing applications against HDFS should prefer this interface to directly accessing functionality in DistributedFileSystem or DFSClient. Note that this is distinct from the similarly-named DFSAdmin, which is a class that provides the functionality for the CLI `hdfs dfsadmin ...' commands.

Constructor Summary

Constructors

Constructor and Description
HdfsAdmin(URI uri, org.apache.hadoop.conf.Configuration conf) Create a new HdfsAdmin client.

Method Summary

Methods

Modifier and Type	Method and Description
long	addCacheDirective(CacheDirectiveInfo info, EnumSet<CacheFlag> flags) Add a new CacheDirectiveInfo.
void	addCachePool(CachePoolInfo info) Add a cache pool.
void	allowSnapshot(org.apache.hadoop.fs.Path path) Allow snapshot on a directory.
void	clearQuota(org.apache.hadoop.fs.Path src) Clear the namespace quota (count of files, directories and sym links) for a directory.
void	clearQuotaByStorageType(org.apache.hadoop.fs.Path src, org.apache.hadoop.fs.StorageType type) Clear the space quota by storage type for a directory.
void	clearSpaceQuota(org.apache.hadoop.fs.Path src) Clear the storage space quota (size of files) for a directory.
void	createEncryptionZone(org.apache.hadoop.fs.Path path, String keyName) Deprecated.
void	createEncryptionZone(org.apache.hadoop.fs.Path path, String keyName, EnumSet<CreateEncryptionZoneFlag> flags) Create an encryption zone rooted at an empty existing directory, using the specified encryption key.
void	disallowSnapshot(org.apache.hadoop.fs.Path path) Disallow snapshot on a directory.
Collection<? extends org.apache.hadoop.fs.BlockStoragePolicySpi>	getAllStoragePolicies() Retrieve all the storage policies supported by HDFS file system.
EncryptionZone	getEncryptionZoneForPath(org.apache.hadoop.fs.Path path) Get the path of the encryption zone for a given file or directory.
org.apache.hadoop.fs.FileEncryptionInfo	getFileEncryptionInfo(org.apache.hadoop.fs.Path path) Returns the FileEncryptionInfo on the HdfsFileStatus for the given path.
DFSInotifyEventInputStream	getInotifyEventStream() Exposes a stream of namesystem events.
DFSInotifyEventInputStream	getInotifyEventStream(long lastReadTxid) A version of getInotifyEventStream() meant for advanced users who are aware of HDFS edits up to lastReadTxid (e.g.
org.apache.hadoop.crypto.key.KeyProvider	getKeyProvider() Get KeyProvider if present.
org.apache.hadoop.fs.BlockStoragePolicySpi	getStoragePolicy(org.apache.hadoop.fs.Path src) Query the effective storage policy ID for the given file or directory.
org.apache.hadoop.fs.RemoteIterator<CacheDirectiveEntry>	listCacheDirectives(CacheDirectiveInfo filter) List cache directives.
org.apache.hadoop.fs.RemoteIterator<CachePoolEntry>	listCachePools() List all cache pools.
org.apache.hadoop.fs.RemoteIterator<EncryptionZone>	listEncryptionZones() Returns a RemoteIterator which can be used to list the encryption zones in HDFS.
org.apache.hadoop.fs.RemoteIterator<org.apache.hadoop.hdfs.protocol.OpenFileEntry>	listOpenFiles() Returns a RemoteIterator which can be used to list all open files currently managed by the NameNode.
void	modifyCacheDirective(CacheDirectiveInfo info, EnumSet<CacheFlag> flags) Modify a CacheDirective.
void	modifyCachePool(CachePoolInfo info) Modify an existing cache pool.
void	provisionEncryptionZoneTrash(org.apache.hadoop.fs.Path path) Provision a trash directory for a given encryption zone.
void	removeCacheDirective(long id) Remove a CacheDirective.
void	removeCachePool(String poolName) Remove a cache pool.
void	setQuota(org.apache.hadoop.fs.Path src, long quota) Set the namespace quota (count of files, directories, and sym links) for a directory.
void	setQuotaByStorageType(org.apache.hadoop.fs.Path src, org.apache.hadoop.fs.StorageType type, long quota) Set the quota by storage type for a directory.
void	setSpaceQuota(org.apache.hadoop.fs.Path src, long spaceQuota) Set the storage space quota (size of files) for a directory.
void	setStoragePolicy(org.apache.hadoop.fs.Path src, String policyName) Set the source path to the specified storage policy.
void	unsetStoragePolicy(org.apache.hadoop.fs.Path src) Unset the storage policy set for a given file or directory.

Methods inherited from class java.lang.Object

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

Constructor Detail

HdfsAdmin

public HdfsAdmin(URI uri,
         org.apache.hadoop.conf.Configuration conf)
          throws IOException

Create a new HdfsAdmin client.

Parameters:

uri - the unique URI of the HDFS file system to administer

conf - configuration

Throws:

IOException - in the event the file system could not be created

Method Detail

setQuota

public void setQuota(org.apache.hadoop.fs.Path src,
            long quota)
              throws IOException

Set the namespace quota (count of files, directories, and sym links) for a directory.

Parameters:

src - the path to set the quota for

quota - the value to set for the quota

Throws:

IOException - in the event of error

clearQuota

public void clearQuota(org.apache.hadoop.fs.Path src)
                throws IOException

Clear the namespace quota (count of files, directories and sym links) for a directory.

Parameters:

src - the path to clear the quota of

Throws:

IOException - in the event of error

setSpaceQuota

public void setSpaceQuota(org.apache.hadoop.fs.Path src,
                 long spaceQuota)
                   throws IOException

Set the storage space quota (size of files) for a directory. Note that directories and sym links do not occupy storage space.

Parameters:

src - the path to set the space quota of

spaceQuota - the value to set for the space quota

Throws:

IOException - in the event of error

clearSpaceQuota

public void clearSpaceQuota(org.apache.hadoop.fs.Path src)
                     throws IOException

Clear the storage space quota (size of files) for a directory. Note that directories and sym links do not occupy storage space.

Parameters:

src - the path to clear the space quota of

Throws:

IOException - in the event of error

setQuotaByStorageType

public void setQuotaByStorageType(org.apache.hadoop.fs.Path src,
                         org.apache.hadoop.fs.StorageType type,
                         long quota)
                           throws IOException

Set the quota by storage type for a directory. Note that directories and sym links do not occupy storage type quota.

Parameters:

src - the target directory to set the quota by storage type

type - the storage type to set for quota by storage type

quota - the value to set for quota by storage type

Throws:

IOException - in the event of error

clearQuotaByStorageType

public void clearQuotaByStorageType(org.apache.hadoop.fs.Path src,
                           org.apache.hadoop.fs.StorageType type)
                             throws IOException

Clear the space quota by storage type for a directory. Note that directories and sym links do not occupy storage type quota.

Parameters:

src - the target directory to clear the quota by storage type

type - the storage type to clear for quota by storage type

Throws:

IOException - in the event of error

allowSnapshot

public void allowSnapshot(org.apache.hadoop.fs.Path path)
                   throws IOException

Allow snapshot on a directory.

Parameters:

path - The path of the directory where snapshots will be taken.

Throws:

IOException

disallowSnapshot

public void disallowSnapshot(org.apache.hadoop.fs.Path path)
                      throws IOException

Disallow snapshot on a directory.

Parameters:

path - The path of the snapshottable directory.

Throws:

IOException

addCacheDirective

public long addCacheDirective(CacheDirectiveInfo info,
                     EnumSet<CacheFlag> flags)
                       throws IOException

Add a new CacheDirectiveInfo.

Parameters:

info - Information about a directive to add.

flags - CacheFlags to use for this operation.

Returns:

the ID of the directive that was created.

Throws:

IOException - if the directive could not be added

modifyCacheDirective

public void modifyCacheDirective(CacheDirectiveInfo info,
                        EnumSet<CacheFlag> flags)
                          throws IOException

Modify a CacheDirective.

Parameters:

info - Information about the directive to modify. You must set the ID to indicate which CacheDirective you want to modify.

flags - CacheFlags to use for this operation.

Throws:

IOException - if the directive could not be modified

removeCacheDirective

public void removeCacheDirective(long id)
                          throws IOException

Remove a CacheDirective.

Parameters:

id - identifier of the CacheDirectiveInfo to remove

Throws:

IOException - if the directive could not be removed

listCacheDirectives

public org.apache.hadoop.fs.RemoteIterator<CacheDirectiveEntry> listCacheDirectives(CacheDirectiveInfo filter)
                                                                             throws IOException

List cache directives. Incrementally fetches results from the server.

Parameters:

filter - Filter parameters to use when listing the directives, null to list all directives visible to us.

Returns:

A RemoteIterator which returns CacheDirectiveInfo objects.

Throws:

IOException

addCachePool

public void addCachePool(CachePoolInfo info)
                  throws IOException

Add a cache pool.

Parameters:

info - The request to add a cache pool.

Throws:

IOException - If the request could not be completed.

modifyCachePool

public void modifyCachePool(CachePoolInfo info)
                     throws IOException

Modify an existing cache pool.

Parameters:

info - The request to modify a cache pool.

Throws:

IOException - If the request could not be completed.

removeCachePool

public void removeCachePool(String poolName)
                     throws IOException

Remove a cache pool.

Parameters:

poolName - Name of the cache pool to remove.

Throws:

IOException - if the cache pool did not exist, or could not be removed.

listCachePools

public org.apache.hadoop.fs.RemoteIterator<CachePoolEntry> listCachePools()
                                                                   throws IOException

List all cache pools.

Returns:

A remote iterator from which you can get CachePoolEntry objects. Requests will be made as needed.

Throws:

IOException - If there was an error listing cache pools.

getKeyProvider

public org.apache.hadoop.crypto.key.KeyProvider getKeyProvider()
                                                        throws IOException

Get KeyProvider if present.

Returns:

the key provider if encryption is enabled on HDFS. Otherwise, it returns null.

Throws:

IOException - on RPC exception to the NN.

createEncryptionZone

@Deprecated
public void createEncryptionZone(org.apache.hadoop.fs.Path path,
                                   String keyName)
                          throws IOException,
                                 org.apache.hadoop.security.AccessControlException,
                                 FileNotFoundException

Deprecated.

Create an encryption zone rooted at an empty existing directory, using the specified encryption key. An encryption zone has an associated encryption key used when reading and writing files within the zone.

Parameters:

path - The path of the root of the encryption zone. Must refer to an empty, existing directory.

keyName - Name of key available at the KeyProvider.

Throws:

IOException - if there was a general IO exception

org.apache.hadoop.security.AccessControlException - if the caller does not have access to path

FileNotFoundException - if the path does not exist

createEncryptionZone

public void createEncryptionZone(org.apache.hadoop.fs.Path path,
                        String keyName,
                        EnumSet<CreateEncryptionZoneFlag> flags)
                          throws IOException,
                                 org.apache.hadoop.security.AccessControlException,
                                 FileNotFoundException,
                                 org.apache.hadoop.HadoopIllegalArgumentException

Create an encryption zone rooted at an empty existing directory, using the specified encryption key. An encryption zone has an associated encryption key used when reading and writing files within the zone. Additional options, such as provisioning the trash directory, can be specified using CreateEncryptionZoneFlag flags.

Parameters:

path - The path of the root of the encryption zone. Must refer to an empty, existing directory.

keyName - Name of key available at the KeyProvider.

flags - flags for this operation.

Throws:

IOException - if there was a general IO exception

org.apache.hadoop.security.AccessControlException - if the caller does not have access to path

FileNotFoundException - if the path does not exist

org.apache.hadoop.HadoopIllegalArgumentException - if the flags are invalid

provisionEncryptionZoneTrash

public void provisionEncryptionZoneTrash(org.apache.hadoop.fs.Path path)
                                  throws IOException

Provision a trash directory for a given encryption zone.

Parameters:

path - the root of the encryption zone

Throws:

IOException - if the trash directory can not be created.

getEncryptionZoneForPath

public EncryptionZone getEncryptionZoneForPath(org.apache.hadoop.fs.Path path)
                                        throws IOException,
                                               org.apache.hadoop.security.AccessControlException

Get the path of the encryption zone for a given file or directory.

Parameters:

path - The path to get the ez for.

Returns:

An EncryptionZone, or null if path does not exist or is not in an ez.

Throws:

IOException - if there was a general IO exception

org.apache.hadoop.security.AccessControlException - if the caller does not have access to path

listEncryptionZones

public org.apache.hadoop.fs.RemoteIterator<EncryptionZone> listEncryptionZones()
                                                                        throws IOException

Returns a RemoteIterator which can be used to list the encryption zones in HDFS. For large numbers of encryption zones, the iterator will fetch the list of zones in a number of small batches.

Since the list is fetched in batches, it does not represent a consistent snapshot of the entire list of encryption zones.

This method can only be called by HDFS superusers.

Throws:

IOException

getFileEncryptionInfo

public org.apache.hadoop.fs.FileEncryptionInfo getFileEncryptionInfo(org.apache.hadoop.fs.Path path)
                                                              throws IOException

Returns the FileEncryptionInfo on the HdfsFileStatus for the given path. The return value can be null if the path points to a directory, or a file that is not in an encryption zone.

Throws:

FileNotFoundException - if the path does not exist.

org.apache.hadoop.security.AccessControlException - if no execute permission on parent path.

IOException

getInotifyEventStream

public DFSInotifyEventInputStream getInotifyEventStream()
                                                 throws IOException

Exposes a stream of namesystem events. Only events occurring after the stream is created are available. See DFSInotifyEventInputStream for information on stream usage. See Event for information on the available events.

Inotify users may want to tune the following HDFS parameters to ensure that enough extra HDFS edits are saved to support inotify clients that fall behind the current state of the namespace while reading events. The default parameter values should generally be reasonable. If edits are deleted before their corresponding events can be read, clients will see a MissingEventsException on DFSInotifyEventInputStream method calls. It should generally be sufficient to tune these parameters: dfs.namenode.num.extra.edits.retained dfs.namenode.max.extra.edits.segments.retained Parameters that affect the number of created segments and the number of edits that are considered necessary, i.e. do not count towards the dfs.namenode.num.extra.edits.retained quota): dfs.namenode.checkpoint.period dfs.namenode.checkpoint.txns dfs.namenode.num.checkpoints.retained dfs.ha.log-roll.period

It is recommended that local journaling be configured (dfs.namenode.edits.dir) for inotify (in addition to a shared journal) so that edit transfers from the shared journal can be avoided.

Throws:

IOException - If there was an error obtaining the stream.

getInotifyEventStream

public DFSInotifyEventInputStream getInotifyEventStream(long lastReadTxid)
                                                 throws IOException

A version of getInotifyEventStream() meant for advanced users who are aware of HDFS edits up to lastReadTxid (e.g. because they have access to an FSImage inclusive of lastReadTxid) and only want to read events after this point.

Throws:

IOException

setStoragePolicy

public void setStoragePolicy(org.apache.hadoop.fs.Path src,
                    String policyName)
                      throws IOException

Set the source path to the specified storage policy.

Parameters:

src - The source path referring to either a directory or a file.

policyName - The name of the storage policy.

Throws:

IOException

unsetStoragePolicy

public void unsetStoragePolicy(org.apache.hadoop.fs.Path src)
                        throws IOException

Unset the storage policy set for a given file or directory.

Parameters:

src - file or directory path.

Throws:

IOException

getStoragePolicy

public org.apache.hadoop.fs.BlockStoragePolicySpi getStoragePolicy(org.apache.hadoop.fs.Path src)
                                                            throws IOException

Query the effective storage policy ID for the given file or directory.

Parameters:

src - file or directory path.

Returns:

storage policy for the given file or directory.

Throws:

IOException

getAllStoragePolicies

public Collection<? extends org.apache.hadoop.fs.BlockStoragePolicySpi> getAllStoragePolicies()
                                                                                       throws IOException

Retrieve all the storage policies supported by HDFS file system.

Returns:

all storage policies supported by HDFS file system.

Throws:

IOException

listOpenFiles

public org.apache.hadoop.fs.RemoteIterator<org.apache.hadoop.hdfs.protocol.OpenFileEntry> listOpenFiles()
                                                                                                 throws IOException

Returns a RemoteIterator which can be used to list all open files currently managed by the NameNode. For large numbers of open files, iterator will fetch the list in batches of configured size.

Since the list is fetched in batches, it does not represent a consistent snapshot of the all open files.

This method can only be called by HDFS superusers.

Throws:

IOException