NameNode (Hadoop 1.2.2-SNAPSHOT API)

java.lang.Object
- org.apache.hadoop.hdfs.server.namenode.NameNode

所有已实现的接口:

ClientProtocol, FSConstants, DatanodeProtocol, NamenodeProtocol, VersionedProtocol, RefreshAuthorizationPolicyProtocol, RefreshUserMappingsProtocol
```
public class NameNode
extends Object
implements ClientProtocol, DatanodeProtocol, NamenodeProtocol, FSConstants, RefreshAuthorizationPolicyProtocol, RefreshUserMappingsProtocol
```
NameNode serves as both directory namespace manager and "inode table" for the Hadoop DFS. There is a single NameNode running in any DFS deployment. (Well, except when there is a second backup/failover NameNode.) The NameNode controls two critical tables: 1) filename->blocksequence (namespace) 2) block->machinelist ("inodes") The first table is stored on disk and is very precious. The second table is rebuilt every time the NameNode comes up. 'NameNode' refers to both this class as well as the 'NameNode server'. The 'FSNamesystem' class actually performs most of the filesystem management. The majority of the 'NameNode' class itself is concerned with exposing the IPC interface and the http server to the outside world, plus some configuration management. NameNode implements the ClientProtocol interface, which allows clients to ask for DFS services. ClientProtocol is not designed for direct use by authors of DFS client code. End-users should instead use the org.apache.nutch.hadoop.fs.FileSystem class. NameNode also implements the DatanodeProtocol interface, used by DataNode programs that actually store DFS data blocks. These methods are invoked repeatedly and automatically by all the DataNodes in a DFS deployment. NameNode also implements the NamenodeProtocol interface, used by secondary namenodes or rebalancing processes to get partial namenode's state, for example partial blocksMap etc.

嵌套类概要
- 从接口继承的嵌套类/接口 org.apache.hadoop.hdfs.protocol.FSConstants
  FSConstants.DatanodeReportType, FSConstants.SafeModeAction, FSConstants.UpgradeAction

字段概要

字段
限定符和类型	字段和说明
`static int`	`DEFAULT_PORT`
`static org.apache.commons.logging.Log`	`LOG`
`protected InetSocketAddress`	`serviceRPCAddress` RPC server for DN address
`static org.apache.commons.logging.Log`	`stateChangeLog`

从接口继承的字段 org.apache.hadoop.hdfs.protocol.ClientProtocol
GET_STATS_CAPACITY_IDX, GET_STATS_CORRUPT_BLOCKS_IDX, GET_STATS_MISSING_BLOCKS_IDX, GET_STATS_REMAINING_IDX, GET_STATS_UNDER_REPLICATED_IDX, GET_STATS_USED_IDX, versionID

从接口继承的字段 org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol
DISK_ERROR, DNA_ACCESSKEYUPDATE, DNA_BALANCERBANDWIDTHUPDATE, DNA_FINALIZE, DNA_INVALIDATE, DNA_RECOVERBLOCK, DNA_REGISTER, DNA_SHUTDOWN, DNA_TRANSFER, DNA_UNKNOWN, FATAL_DISK_ERROR, INVALID_BLOCK, NOTIFY, versionID

从接口继承的字段 org.apache.hadoop.hdfs.server.protocol.NamenodeProtocol
versionID

从接口继承的字段 org.apache.hadoop.hdfs.protocol.FSConstants
BLOCKREPORT_INITIAL_DELAY, BLOCKREPORT_INTERVAL, BUFFER_SIZE, DEFAULT_BLOCK_SIZE, DEFAULT_DATA_SOCKET_SIZE, HEARTBEAT_INTERVAL, LAYOUT_VERSION, LEASE_HARDLIMIT_PERIOD, LEASE_RECOVER_PERIOD, LEASE_SOFTLIMIT_PERIOD, MAX_PATH_DEPTH, MAX_PATH_LENGTH, MIN_BLOCKS_FOR_WRITE, QUOTA_DONT_SET, QUOTA_RESET, SIZE_OF_INTEGER, SMALL_BUFFER_SIZE

从接口继承的字段 org.apache.hadoop.security.authorize.RefreshAuthorizationPolicyProtocol
versionID

从接口继承的字段 org.apache.hadoop.security.RefreshUserMappingsProtocol
versionID

构造器概要

构造器
构造器和说明

NameNode(Configuration conf)
Start NameNode.

构造器
构造器和说明
`NameNode(Configuration conf)` Start NameNode.

方法概要

方法
限定符和类型	方法和说明
`void`	`abandonBlock(Block b, String src, String holder)` The client needs to give up on the block.
`LocatedBlock`	`addBlock(String src, String clientName)` Stub for 0.20 clients that don't support HDFS-630
`LocatedBlock`	`addBlock(String src, String clientName, DatanodeInfo[] excludedNodes)` A client that wants to write an additional block to the indicated filename (which must currently be open for writing) should call addBlock().
`LocatedBlock`	`append(String src, String clientName)` Append to the end of the file.
`void`	`blockReceived(DatanodeRegistration nodeReg, Block[] blocks, String[] delHints)` blockReceived() allows the DataNode to tell the NameNode about recently-received block data, with a hint for pereferred replica to be deleted when there is any excessive blocks.
`DatanodeCommand`	`blockReport(DatanodeRegistration nodeReg, long[] blocks)` blockReport() tells the NameNode about all the locally-stored blocks.
`void`	`blocksBeingWrittenReport(DatanodeRegistration nodeReg, long[] blocks)` add new replica blocks to the Inode to target mapping also add the Inode file to DataNodeDesc
`void`	`cancelDelegationToken(Token<DelegationTokenIdentifier> token)` Cancel an existing delegation token.
`void`	`commitBlockSynchronization(Block block, long newgenerationstamp, long newlength, boolean closeFile, boolean deleteblock, DatanodeID[] newtargets)` Commit block synchronization in lease recovery
`boolean`	`complete(String src, String clientName)` The client is done writing data to the given filename, and would like to complete it.
`void`	`concat(String trg, String[] src)` Moves blocks from srcs to trg and delete srcs
`void`	`create(String src, FsPermission masked, String clientName, boolean overwrite, boolean createParent, short replication, long blockSize)` Create a new file entry in the namespace.
`void`	`create(String src, FsPermission masked, String clientName, boolean overwrite, short replication, long blockSize)` 已过时。
`static NameNode`	`createNameNode(String[] argv, Configuration conf)`
`boolean`	`delete(String src)` 已过时。
`boolean`	`delete(String src, boolean recursive)` Delete the given file or directory from the file system.
`UpgradeStatusReport`	`distributedUpgradeProgress(FSConstants.UpgradeAction action)` Report distributed upgrade progress or force current upgrade to proceed.
`void`	`errorReport(DatanodeRegistration nodeReg, int errorCode, String msg)` errorReport() tells the NameNode about something that has gone awry.
`void`	`finalizeUpgrade()` Finalize previous upgrade.
`static void`	`format(Configuration conf)` Format a new filesystem.
`void`	`fsync(String src, String clientName)` Write all metadata for this file into persistent storage.
`static InetSocketAddress`	`getAddress(Configuration conf)`
`static InetSocketAddress`	`getAddress(String address)`
`ExportedBlockKeys`	`getBlockKeys()` Get the current block keys
`LocatedBlocks`	`getBlockLocations(String src, long offset, long length)` Get locations of the blocks of the specified file within the specified range.
`BlocksWithLocations`	`getBlocks(DatanodeInfo datanode, long size)` return a list of blocks & their locations on `datanode` whose total size is `size`
`ContentSummary`	`getContentSummary(String path)` Get `ContentSummary` rooted at the specified directory.
`DatanodeInfo[]`	`getDatanodeReport(FSConstants.DatanodeReportType type)` Get a report on the system's current datanodes.
`Token<DelegationTokenIdentifier>`	`getDelegationToken(Text renewer)` Get a valid Delegation Token.
`long`	`getEditLogSize()` Returns the size of the current edit log.
`HdfsFileStatus`	`getFileInfo(String src)` Get the file info for a specific file.
`FSImage`	`getFSImage()`
`File`	`getFsImageName()` Returns the name of the fsImage file
`File[]`	`getFsImageNameCheckpoint()` Returns the name of the fsImage file uploaded by periodic checkpointing
`InetSocketAddress`	`getHttpAddress()` Returns the address of the NameNodes http server, which is used to access the name-node web UI.
`static String`	`getHttpUriScheme()`
`static String`	`getInfoServer(Configuration conf)`
`DirectoryListing`	`getListing(String src, byte[] startAfter)` Get a partial listing of the indicated directory
`InetSocketAddress`	`getNameNodeAddress()` Returns the address on which the NameNodes is listening to.
`static NameNodeInstrumentation`	`getNameNodeMetrics()`
`FSNamesystem`	`getNamesystem()`
`long`	`getPreferredBlockSize(String filename)` Get the block size for the given file.
`long`	`getProtocolVersion(String protocol, long clientVersion)` Return protocol version corresponding to protocol interface.
`static InetSocketAddress`	`getServiceAddress(Configuration conf, boolean fallback)` Fetches the address for services to use when connecting to namenode based on the value of fallback returns null if the special address is not specified or returns the default namenode address to be used by both clients and services.
`protected InetSocketAddress`	`getServiceRpcServerAddress(Configuration conf)` Given a configuration get the address of the service rpc server If the service rpc is not configured returns null
`long[]`	`getStats()` Get a set of statistics about the filesystem.
`static URI`	`getUri(InetSocketAddress namenode)`
`boolean`	`isFileClosed(String src)` Get the close status of a file
`boolean`	`isInSafeMode()` Is the cluster currently in safe mode?
`void`	`join()` Wait for service to finish.
`static void`	`main(String[] argv)`
`void`	`metaSave(String filename)` Dumps namenode state into specified file
`boolean`	`mkdirs(String src, FsPermission masked)` Create a directory (or hierarchy of directories) with the given name and permission.
`long`	`nextGenerationStamp(Block block, boolean fromNN)` Get the next GenerationStamp to be associated with the specified block.
`UpgradeCommand`	`processUpgradeCommand(UpgradeCommand comm)` This is a very general way to send a command to the name-node during distributed upgrade process.
`boolean`	`recoverLease(String src, String clientName)` Start lease recovery
`void`	`refreshNodes()` Refresh the list of datanodes that the namenode should allow to connect.
`void`	`refreshServiceAcl()` Refresh the service-level authorization policy in-effect.
`void`	`refreshSuperUserGroupsConfiguration()` Refresh superuser proxy group list
`void`	`refreshUserToGroupsMappings()` Refresh user to group mappings.
`DatanodeRegistration`	`register(DatanodeRegistration nodeReg)` Register Datanode.
`boolean`	`rename(String src, String dst)` Rename an item in the file system namespace.
`long`	`renewDelegationToken(Token<DelegationTokenIdentifier> token)` Renew an existing delegation token.
`void`	`renewLease(String clientName)` Client programs can cause stateful changes in the NameNode that affect other clients.
`void`	`reportBadBlocks(LocatedBlock[] blocks)` The client has detected an error on the specified located blocks and is reporting them to the server.
`CheckpointSignature`	`rollEditLog()` Roll the edit log.
`void`	`rollFsImage()` Roll the image
`void`	`saveNamespace()` Save namespace image.
`DatanodeCommand[]`	`sendHeartbeat(DatanodeRegistration nodeReg, long capacity, long dfsUsed, long remaining, int xmitsInProgress, int xceiverCount)` Data node notify the name node that it is alive Return an array of block-oriented commands for the datanode to execute.
`void`	`setBalancerBandwidth(long bandwidth)` Tell all datanodes to use a new, non-persistent bandwidth value for dfs.balance.bandwidthPerSec.
`void`	`setNamesystem(FSNamesystem ns)`
`void`	`setOwner(String src, String username, String groupname)` Set owner of a path (i.e. a file or a directory).
`void`	`setPermission(String src, FsPermission permissions)` Set permissions for an existing file/directory.
`void`	`setQuota(String path, long namespaceQuota, long diskspaceQuota)` Set the quota for a directory.
`boolean`	`setReplication(String src, short replication)` Set replication for an existing file.
`protected void`	`setRpcServiceServerAddress(Configuration conf)` Modifies the configuration passed to contain the service rpc address setting
`boolean`	`setSafeMode(FSConstants.SafeModeAction action)` Enter, leave or get safe mode.
`static void`	`setServiceAddress(Configuration conf, String address)` Set the configuration property for the service rpc address to address
`void`	`setTimes(String src, long mtime, long atime)` Sets the modification and access time of the file to the specified time.
`void`	`stop()` Stop all NameNode threads and wait for all to finish.
`void`	`verifyRequest(DatanodeRegistration nodeReg)` Verify request.
`void`	`verifyVersion(int version)` Verify version.
`NamespaceInfo`	`versionRequest()`

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 字段详细资料
  - DEFAULT_PORT
```
public static final int DEFAULT_PORT
```
    另请参阅:
    常量字段值
  - LOG
```
public static final org.apache.commons.logging.Log LOG
```
  - stateChangeLog
```
public static final org.apache.commons.logging.Log stateChangeLog
```
  - serviceRPCAddress
```
protected InetSocketAddress serviceRPCAddress
```
    RPC server for DN address
- 构造器详细资料
  - NameNode
```
public NameNode(Configuration conf)
         throws IOException
```
    Start NameNode.
    The name-node can be started with one of the following startup options:
    - REGULAR - normal name node startup
    - FORMAT - format name node
    - UPGRADE - start the cluster
    - RECOVER - recover name node metadata
    - ROLLBACK - roll the cluster back to the previous state
    The option is passed via configuration field: dfs.namenode.startup The conf will be modified to reflect the actual ports on which the NameNode is up and running if the user passes the port as zero in the conf.
    参数:
    conf - confirguration
    
    抛出:
    
    IOException
- 方法详细资料
  - getProtocolVersion
```
public long getProtocolVersion(String protocol,
                      long clientVersion)
                        throws IOException
```
    从接口复制的说明: VersionedProtocol
    
    Return protocol version corresponding to protocol interface.
    
    指定者:
    
    getProtocolVersion 在接口中 VersionedProtocol
    
    参数:
    protocol - The classname of the protocol interface
    clientVersion - The version of the protocol that the client speaks
    
    返回:
    the version that the server will speak
    
    抛出:
    
    IOException
  - format
```
public static void format(Configuration conf)
                   throws IOException
```
    Format a new filesystem. Destroys any filesystem that may already exist at this location.
    
    抛出:
    
    IOException
  - setNamesystem
```
public void setNamesystem(FSNamesystem ns)
```
  - getNamesystem
```
public FSNamesystem getNamesystem()
```
  - getNameNodeMetrics
```
public static NameNodeInstrumentation getNameNodeMetrics()
```
  - getAddress
```
public static InetSocketAddress getAddress(String address)
```
  - setServiceAddress
```
public static void setServiceAddress(Configuration conf,
                     String address)
```
    Set the configuration property for the service rpc address to address
  - getServiceAddress
```
public static InetSocketAddress getServiceAddress(Configuration conf,
                                  boolean fallback)
```
    Fetches the address for services to use when connecting to namenode based on the value of fallback returns null if the special address is not specified or returns the default namenode address to be used by both clients and services. Services here are datanodes, backup node, any non client connection
  - getAddress
```
public static InetSocketAddress getAddress(Configuration conf)
```
  - getUri
```
public static URI getUri(InetSocketAddress namenode)
```
  - getServiceRpcServerAddress
```
protected InetSocketAddress getServiceRpcServerAddress(Configuration conf)
                                                throws IOException
```
    Given a configuration get the address of the service rpc server If the service rpc is not configured returns null
    
    抛出:
    
    IOException
  - setRpcServiceServerAddress
```
protected void setRpcServiceServerAddress(Configuration conf)
```
    Modifies the configuration passed to contain the service rpc address setting
  - getInfoServer
```
public static String getInfoServer(Configuration conf)
```
  - getHttpUriScheme
```
public static String getHttpUriScheme()
```
    返回:
    "https" if KSSL should be used, "http" if security is disabled or SPNEGO is enabled.
  - join
```
public void join()
```
    Wait for service to finish. (Normally, it runs forever.)
  - stop
```
public void stop()
```
    Stop all NameNode threads and wait for all to finish.
  - getBlocks
```
public BlocksWithLocations getBlocks(DatanodeInfo datanode,
                            long size)
                              throws IOException
```
    return a list of blocks & their locations on datanode whose total size is size
    
    指定者:
    
    getBlocks 在接口中 NamenodeProtocol
    
    参数:
    datanode - on which blocks are located
    size - total size of blocks
    
    返回:
    a list of blocks & their locations
    
    抛出:
    
    IOException
  - getDelegationToken
```
public Token<DelegationTokenIdentifier> getDelegationToken(Text renewer)
                                                    throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Get a valid Delegation Token.
    
    指定者:
    
    getDelegationToken 在接口中 ClientProtocol
    
    参数:
    renewer - the designated renewer for the token
    
    返回:
    Token
    
    抛出:
    
    IOException
  - renewDelegationToken
```
public long renewDelegationToken(Token<DelegationTokenIdentifier> token)
                          throws SecretManager.InvalidToken,
                                 IOException
```
    从接口复制的说明: ClientProtocol
    
    Renew an existing delegation token.
    
    指定者:
    
    renewDelegationToken 在接口中 ClientProtocol
    
    参数:
    token - delegation token obtained earlier
    
    返回:
    the new expiration time
    
    抛出:
    
    IOException
    
    SecretManager.InvalidToken
  - cancelDelegationToken
```
public void cancelDelegationToken(Token<DelegationTokenIdentifier> token)
                           throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Cancel an existing delegation token.
    
    指定者:
    
    cancelDelegationToken 在接口中 ClientProtocol
    
    参数:
    token - delegation token
    
    抛出:
    
    IOException
  - getBlockLocations
```
public LocatedBlocks getBlockLocations(String src,
                              long offset,
                              long length)
                                throws IOException
```
    Get locations of the blocks of the specified file within the specified range. DataNode locations for each block are sorted by the proximity to the client.
    Return LocatedBlocks which contains file length, blocks and their locations. DataNode locations for each block are sorted by the distance to the client's address.
    The client will then have to contact one of the indicated DataNodes to obtain the actual data.
    
    指定者:
    
    getBlockLocations 在接口中 ClientProtocol
    
    参数:
    src - file name
    offset - range start offset
    length - range length
    
    返回:
    file length and array of blocks with their locations
    
    抛出:
    
    IOException
  - create
```
@Deprecated
public void create(String src,
                     FsPermission masked,
                     String clientName,
                     boolean overwrite,
                     short replication,
                     long blockSize)
            throws IOException
```
    已过时。
    
    从接口复制的说明: ClientProtocol
    
    Create a new file entry in the namespace.
    
    指定者:
    
    create 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - create
```
public void create(String src,
          FsPermission masked,
          String clientName,
          boolean overwrite,
          boolean createParent,
          short replication,
          long blockSize)
            throws IOException
```
    Create a new file entry in the namespace.
    This will create an empty file specified by the source path. The path should reflect a full path originated at the root. The name-node does not have a notion of "current" directory for a client.
    Once created, the file is visible and available for read to other clients. Although, other clients cannot ClientProtocol.delete(String), re-create or ClientProtocol.rename(String, String) it until the file is completed or explicitly as a result of lease expiration.
    Blocks have a maximum size. Clients that intend to create multi-block files must also use ClientProtocol.addBlock(String, String).
    
    指定者:
    
    create 在接口中 ClientProtocol
    
    参数:
    src - path of the file being created.
    masked - masked permission.
    clientName - name of the current client.
    overwrite - indicates whether the file should be overwritten if it already exists.
    createParent - create missing parent directory if true
    replication - block replication factor.
    blockSize - maximum block size.
    
    抛出:
    
    AccessControlException - if permission to create file is denied by the system. As usually on the client side the exception will be wrapped into RemoteException.
    
    QuotaExceededException - if the file creation violates any quota restriction
    
    IOException - if other errors occur.
  - append
```
public LocatedBlock append(String src,
                  String clientName)
                    throws IOException
```
    Append to the end of the file.
    
    指定者:
    
    append 在接口中 ClientProtocol
    
    参数:
    src - path of the file being created.
    clientName - name of the current client.
    
    返回:
    information about the last partial block if any.
    
    抛出:
    
    AccessControlException - if permission to append file is denied by the system. As usually on the client side the exception will be wrapped into RemoteException. Allows appending to an existing file if the server is configured with the parameter dfs.support.broken.append set to true, otherwise throws an IOException.
    
    IOException - if other errors occur.
  - isFileClosed
```
public boolean isFileClosed(String src)
                     throws IOException
```
    Get the close status of a file
    
    指定者:
    
    isFileClosed 在接口中 ClientProtocol
    
    参数:
    src - The string representation of the path to the file
    
    返回:
    return true if file is closed
    
    抛出:
    
    AccessControlException - permission denied
    
    FileNotFoundException - file src is not found
    
    IOException - If an I/O error occurred
  - recoverLease
```
public boolean recoverLease(String src,
                   String clientName)
                     throws IOException
```
    Start lease recovery
    
    指定者:
    
    recoverLease 在接口中 ClientProtocol
    
    参数:
    src - path of the file to start lease recovery
    clientName - name of the current client
    
    返回:
    true if the file is already closed
    
    抛出:
    
    IOException
  - setReplication
```
public boolean setReplication(String src,
                     short replication)
                       throws IOException
```
    Set replication for an existing file.
    The NameNode sets replication to the new value and returns. The actual block replication is not expected to be performed during this method call. The blocks will be populated or removed in the background as the result of the routine block maintenance procedures.
    
    指定者:
    
    setReplication 在接口中 ClientProtocol
    
    参数:
    src - file name
    replication - new replication
    
    返回:
    true if successful; false if file does not exist or is a directory
    
    抛出:
    
    IOException
  - setPermission
```
public void setPermission(String src,
                 FsPermission permissions)
                   throws IOException
```
    Set permissions for an existing file/directory.
    
    指定者:
    
    setPermission 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - setOwner
```
public void setOwner(String src,
            String username,
            String groupname)
              throws IOException
```
    Set owner of a path (i.e. a file or a directory). The parameters username and groupname cannot both be null.
    
    指定者:
    
    setOwner 在接口中 ClientProtocol
    
    username - If it is null, the original username remains unchanged.
    groupname - If it is null, the original groupname remains unchanged.
    
    抛出:
    
    IOException
  - addBlock
```
public LocatedBlock addBlock(String src,
                    String clientName)
                      throws IOException
```
    Stub for 0.20 clients that don't support HDFS-630
    
    指定者:
    
    addBlock 在接口中 ClientProtocol
    
    返回:
    LocatedBlock allocated block information.
    
    抛出:
    
    IOException
  - addBlock
```
public LocatedBlock addBlock(String src,
                    String clientName,
                    DatanodeInfo[] excludedNodes)
                      throws IOException
```
    从接口复制的说明: ClientProtocol
    
    A client that wants to write an additional block to the indicated filename (which must currently be open for writing) should call addBlock(). addBlock() allocates a new block and datanodes the block data should be replicated to.
    
    指定者:
    
    addBlock 在接口中 ClientProtocol
    
    excludedNodes - a list of nodes that should not be allocated
    
    返回:
    LocatedBlock allocated block information.
    
    抛出:
    
    IOException
  - abandonBlock
```
public void abandonBlock(Block b,
                String src,
                String holder)
                  throws IOException
```
    The client needs to give up on the block.
    
    指定者:
    
    abandonBlock 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - complete
```
public boolean complete(String src,
               String clientName)
                 throws IOException
```
    The client is done writing data to the given filename, and would like to complete it. The function returns whether the file has been closed successfully. If the function returns false, the caller should try again. A call to complete() will not return true until all the file's blocks have been replicated the minimum number of times. Thus, DataNode failures may cause a client to call complete() several times before succeeding.
    
    指定者:
    
    complete 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - reportBadBlocks
```
public void reportBadBlocks(LocatedBlock[] blocks)
                     throws IOException
```
    The client has detected an error on the specified located blocks and is reporting them to the server. For now, the namenode will mark the block as corrupt. In the future we might check the blocks are actually corrupt.
    
    指定者:
    
    reportBadBlocks 在接口中 ClientProtocol
    
    指定者:
    
    reportBadBlocks 在接口中 DatanodeProtocol
    
    参数:
    blocks - Array of located blocks to report
    
    抛出:
    
    IOException
  - nextGenerationStamp
```
public long nextGenerationStamp(Block block,
                       boolean fromNN)
                         throws IOException
```
    Get the next GenerationStamp to be associated with the specified block.
    
    指定者:
    
    nextGenerationStamp 在接口中 DatanodeProtocol
    
    参数:
    block - block
    fromNN - if it is for lease recovery initiated by NameNode
    
    返回:
    a new generation stamp
    
    抛出:
    
    IOException
  - commitBlockSynchronization
```
public void commitBlockSynchronization(Block block,
                              long newgenerationstamp,
                              long newlength,
                              boolean closeFile,
                              boolean deleteblock,
                              DatanodeID[] newtargets)
                                throws IOException
```
    Commit block synchronization in lease recovery
    
    指定者:
    
    commitBlockSynchronization 在接口中 DatanodeProtocol
    
    抛出:
    
    IOException
  - getPreferredBlockSize
```
public long getPreferredBlockSize(String filename)
                           throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Get the block size for the given file.
    
    指定者:
    
    getPreferredBlockSize 在接口中 ClientProtocol
    
    参数:
    filename - The name of the file
    
    返回:
    The number of bytes in each block
    
    抛出:
    
    IOException
  - concat
```
public void concat(String trg,
          String[] src)
            throws IOException
```
    Moves blocks from srcs to trg and delete srcs
    
    指定者:
    
    concat 在接口中 ClientProtocol
    
    参数:
    trg - existing file
    src - - list of existing files (same block size, same replication)
    
    抛出:
    
    IOException - if some arguments are invalid
  - rename
```
public boolean rename(String src,
             String dst)
               throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Rename an item in the file system namespace.
    
    指定者:
    
    rename 在接口中 ClientProtocol
    
    参数:
    src - existing file or directory name.
    dst - new name.
    
    返回:
    true if successful, or false if the old name does not exist or if the new name already belongs to the namespace.
    
    抛出:
    
    IOException - if the new name is invalid.
    
    QuotaExceededException - if the rename would violate any quota restriction
  - delete
```
@Deprecated
public boolean delete(String src)
               throws IOException
```
    已过时。
    
    从接口复制的说明: ClientProtocol
    
    Delete the given file or directory from the file system.
    Any blocks belonging to the deleted files will be garbage-collected.
    
    指定者:
    
    delete 在接口中 ClientProtocol
    
    参数:
    src - existing name.
    
    返回:
    true only if the existing file or directory was actually removed from the file system.
    
    抛出:
    
    IOException
  - delete
```
public boolean delete(String src,
             boolean recursive)
               throws IOException
```
    Delete the given file or directory from the file system.
    same as delete but provides a way to avoid accidentally deleting non empty directories programmatically.
    
    指定者:
    
    delete 在接口中 ClientProtocol
    
    参数:
    src - existing name
    recursive - if true deletes a non empty directory recursively, else throws an exception.
    
    返回:
    true only if the existing file or directory was actually removed from the file system.
    
    抛出:
    
    IOException
  - mkdirs
```
public boolean mkdirs(String src,
             FsPermission masked)
               throws IOException
```
    Create a directory (or hierarchy of directories) with the given name and permission.
    
    指定者:
    
    mkdirs 在接口中 ClientProtocol
    
    参数:
    src - The path of the directory being created
    masked - The masked permission of the directory being created
    
    返回:
    True if the operation success.
    
    抛出:
    
    QuotaExceededException - if the operation would violate any quota restriction.
    
    IOException
  - renewLease
```
public void renewLease(String clientName)
                throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Client programs can cause stateful changes in the NameNode that affect other clients. A client may obtain a file and neither abandon nor complete it. A client might hold a series of locks that prevent other clients from proceeding. Clearly, it would be bad if a client held a bunch of locks that it never gave up. This can happen easily if the client dies unexpectedly.
    So, the NameNode will revoke the locks and live file-creates for clients that it thinks have died. A client tells the NameNode that it is still alive by periodically calling renewLease(). If a certain amount of time passes since the last call to renewLease(), the NameNode assumes the client has died.
    
    指定者:
    
    renewLease 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - getListing
```
public DirectoryListing getListing(String src,
                          byte[] startAfter)
                            throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Get a partial listing of the indicated directory
    
    指定者:
    
    getListing 在接口中 ClientProtocol
    
    参数:
    src - the directory name
    startAfter - the name of the last entry received by the client
    
    返回:
    a partial listing starting after startAfter
    
    抛出:
    
    IOException
  - getFileInfo
```
public HdfsFileStatus getFileInfo(String src)
                           throws IOException
```
    Get the file info for a specific file.
    
    指定者:
    
    getFileInfo 在接口中 ClientProtocol
    
    参数:
    src - The string representation of the path to the file
    
    返回:
    object containing information regarding the file or null if file not found
    
    抛出:
    
    IOException - if permission to access file is denied by the system
  - getStats
```
public long[] getStats()
                throws IOException
```
    从接口复制的说明: ClientProtocol
    Get a set of statistics about the filesystem. Right now, only three values are returned.
    - [0] contains the total storage capacity of the system, in bytes.
    - [1] contains the total used space of the system, in bytes.
    - [2] contains the available storage of the system, in bytes.
    - [3] contains number of under replicated blocks in the system.
    - [4] contains number of blocks with a corrupt replica.
    - [5] contains number of blocks without any good replicas left.
    Use public constants like ClientProtocol.GET_STATS_CAPACITY_IDX in place of actual numbers to index into the array.
    指定者:
    
    getStats 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - getDatanodeReport
```
public DatanodeInfo[] getDatanodeReport(FSConstants.DatanodeReportType type)
                                 throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Get a report on the system's current datanodes. One DatanodeInfo object is returned for each DataNode. Return live datanodes if type is LIVE; dead datanodes if type is DEAD; otherwise all datanodes if type is ALL.
    
    指定者:
    
    getDatanodeReport 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - setSafeMode
```
public boolean setSafeMode(FSConstants.SafeModeAction action)
                    throws IOException
```
    从接口复制的说明: ClientProtocol
    Enter, leave or get safe mode.
    Safe mode is a name node state when it
    1. does not accept changes to name space (read-only), and
    2. does not replicate or delete blocks.
    Safe mode is entered automatically at name node startup. Safe mode can also be entered manually using setSafeMode(SafeModeAction.SAFEMODE_GET).
    At startup the name node accepts data node reports collecting information about block locations. In order to leave safe mode it needs to collect a configurable percentage called threshold of blocks, which satisfy the minimal replication condition. The minimal replication condition is that each block must have at least dfs.replication.min replicas. When the threshold is reached the name node extends safe mode for a configurable amount of time to let the remaining data nodes to check in before it will start replicating missing blocks. Then the name node leaves safe mode.
    If safe mode is turned on manually using setSafeMode(SafeModeAction.SAFEMODE_ENTER) then the name node stays in safe mode until it is manually turned off using setSafeMode(SafeModeAction.SAFEMODE_LEAVE). Current state of the name node can be verified using setSafeMode(SafeModeAction.SAFEMODE_GET)
    Configuration parameters:
    dfs.safemode.threshold.pct is the threshold parameter.
    dfs.safemode.extension is the safe mode extension parameter.
    dfs.replication.min is the minimal replication parameter.
    Special cases:
    The name node does not enter safe mode at startup if the threshold is set to 0 or if the name space is empty.
    If the threshold is set to 1 then all blocks need to have at least minimal replication.
    If the threshold value is greater than 1 then the name node will not be able to turn off safe mode automatically.
    Safe mode can always be turned off manually.
    指定者:
    
    setSafeMode 在接口中 ClientProtocol
    
    参数:
    action -
    
    0 leave safe mode;
    
    1 enter safe mode;
    
    2 get safe mode state.
    返回:
    0 if the safe mode is OFF or
    
    1 if the safe mode is ON.
    抛出:
    
    IOException
  - isInSafeMode
```
public boolean isInSafeMode()
```
    Is the cluster currently in safe mode?
  - saveNamespace
```
public void saveNamespace()
                   throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Save namespace image.
    Saves current namespace into storage directories and reset edits log. Requires superuser privilege and safe mode.
    
    指定者:
    
    saveNamespace 在接口中 ClientProtocol
    
    抛出:
    
    AccessControlException - if the superuser privilege is violated.
    
    IOException - if image creation failed.
  - refreshNodes
```
public void refreshNodes()
                  throws IOException
```
    Refresh the list of datanodes that the namenode should allow to connect. Re-reads conf by creating new Configuration object and uses the files list in the configuration to update the list.
    
    指定者:
    
    refreshNodes 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - getEditLogSize
```
public long getEditLogSize()
                    throws IOException
```
    Returns the size of the current edit log.
    
    指定者:
    
    getEditLogSize 在接口中 NamenodeProtocol
    
    返回:
    The number of bytes in the current edit log.
    
    抛出:
    
    IOException
  - rollEditLog
```
public CheckpointSignature rollEditLog()
                                throws IOException
```
    Roll the edit log.
    
    指定者:
    
    rollEditLog 在接口中 NamenodeProtocol
    
    返回:
    a unique token to identify this transaction.
    
    抛出:
    
    IOException
  - rollFsImage
```
public void rollFsImage()
                 throws IOException
```
    Roll the image
    
    指定者:
    
    rollFsImage 在接口中 NamenodeProtocol
    
    抛出:
    
    IOException
  - finalizeUpgrade
```
public void finalizeUpgrade()
                     throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Finalize previous upgrade. Remove file system state saved during the upgrade. The upgrade will become irreversible.
    
    指定者:
    
    finalizeUpgrade 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - distributedUpgradeProgress
```
public UpgradeStatusReport distributedUpgradeProgress(FSConstants.UpgradeAction action)
                                               throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Report distributed upgrade progress or force current upgrade to proceed.
    
    指定者:
    
    distributedUpgradeProgress 在接口中 ClientProtocol
    
    参数:
    action - FSConstants.UpgradeAction to perform
    
    返回:
    upgrade status information or null if no upgrades are in progress
    
    抛出:
    
    IOException
  - metaSave
```
public void metaSave(String filename)
              throws IOException
```
    Dumps namenode state into specified file
    
    指定者:
    
    metaSave 在接口中 ClientProtocol
    
    抛出:
    
    IOException
  - setBalancerBandwidth
```
public void setBalancerBandwidth(long bandwidth)
                          throws IOException
```
    Tell all datanodes to use a new, non-persistent bandwidth value for dfs.balance.bandwidthPerSec.
    
    指定者:
    
    setBalancerBandwidth 在接口中 ClientProtocol
    
    参数:
    bandwidth - Blanacer bandwidth in bytes per second for all datanodes.
    
    抛出:
    
    IOException
  - getContentSummary
```
public ContentSummary getContentSummary(String path)
                                 throws IOException
```
    Get ContentSummary rooted at the specified directory.
    
    指定者:
    
    getContentSummary 在接口中 ClientProtocol
    
    参数:
    path - The string representation of the path
    
    抛出:
    
    IOException
  - setQuota
```
public void setQuota(String path,
            long namespaceQuota,
            long diskspaceQuota)
              throws IOException
```
    Set the quota for a directory.
    
    指定者:
    
    setQuota 在接口中 ClientProtocol
    
    参数:
    path - The string representation of the path to the directory
    namespaceQuota - Limit on the number of names in the tree rooted at the directory
    diskspaceQuota - Limit on disk space occupied all the files under this directory.
    
    The quota can have three types of values : (1) 0 or more will set the quota to that value, (2) FSConstants.QUOTA_DONT_SET implies the quota will not be changed, and (3) FSConstants.QUOTA_RESET implies the quota will be reset. Any other value is a runtime error.
    
    抛出:
    
    FileNotFoundException - if the path is a file or does not exist
    
    QuotaExceededException - if the directory size is greater than the given quota
    
    IOException
  - fsync
```
public void fsync(String src,
         String clientName)
           throws IOException
```
    Write all metadata for this file into persistent storage. The file must be currently open for writing.
    
    指定者:
    
    fsync 在接口中 ClientProtocol
    
    参数:
    src - The string representation of the path
    clientName - The string representation of the client
    
    抛出:
    
    IOException
  - setTimes
```
public void setTimes(String src,
            long mtime,
            long atime)
              throws IOException
```
    从接口复制的说明: ClientProtocol
    
    Sets the modification and access time of the file to the specified time.
    
    指定者:
    
    setTimes 在接口中 ClientProtocol
    
    参数:
    src - The string representation of the path
    mtime - The number of milliseconds since Jan 1, 1970. Setting mtime to -1 means that modification time should not be set by this call.
    atime - The number of milliseconds since Jan 1, 1970. Setting atime to -1 means that access time should not be set by this call.
    
    抛出:
    
    IOException
  - register
```
public DatanodeRegistration register(DatanodeRegistration nodeReg)
                              throws IOException
```
    从接口复制的说明: DatanodeProtocol
    
    Register Datanode.
    
    指定者:
    
    register 在接口中 DatanodeProtocol
    
    返回:
    updated DatanodeRegistration, which contains new storageID if the datanode did not have one and registration ID for further communication.
    
    抛出:
    
    IOException
    另请参阅:
    DataNode.dnRegistration, FSNamesystem.registerDatanode(DatanodeRegistration)
  - sendHeartbeat
```
public DatanodeCommand[] sendHeartbeat(DatanodeRegistration nodeReg,
                              long capacity,
                              long dfsUsed,
                              long remaining,
                              int xmitsInProgress,
                              int xceiverCount)
                                throws IOException
```
    Data node notify the name node that it is alive Return an array of block-oriented commands for the datanode to execute. This will be either a transfer or a delete operation.
    
    指定者:
    
    sendHeartbeat 在接口中 DatanodeProtocol
    
    抛出:
    
    IOException
  - blockReport
```
public DatanodeCommand blockReport(DatanodeRegistration nodeReg,
                          long[] blocks)
                            throws IOException
```
    从接口复制的说明: DatanodeProtocol
    
    blockReport() tells the NameNode about all the locally-stored blocks. The NameNode returns an array of Blocks that have become obsolete and should be deleted. This function is meant to upload *all* the locally-stored blocks. It's invoked upon startup and then infrequently afterwards.
    
    指定者:
    
    blockReport 在接口中 DatanodeProtocol
    
    blocks - - the block list as an array of longs. Each block is represented as 2 longs. This is done instead of Block[] to reduce memory used by block reports.
    
    返回:
    - the next command for DN to process.
    
    抛出:
    
    IOException
  - blocksBeingWrittenReport
```
public void blocksBeingWrittenReport(DatanodeRegistration nodeReg,
                            long[] blocks)
                              throws IOException
```
    add new replica blocks to the Inode to target mapping also add the Inode file to DataNodeDesc
    
    指定者:
    
    blocksBeingWrittenReport 在接口中 DatanodeProtocol
    
    抛出:
    
    IOException
  - blockReceived
```
public void blockReceived(DatanodeRegistration nodeReg,
                 Block[] blocks,
                 String[] delHints)
                   throws IOException
```
    从接口复制的说明: DatanodeProtocol
    
    blockReceived() allows the DataNode to tell the NameNode about recently-received block data, with a hint for pereferred replica to be deleted when there is any excessive blocks. For example, whenever client code writes a new Block here, or another DataNode copies a Block to this DataNode, it will call blockReceived().
    
    指定者:
    
    blockReceived 在接口中 DatanodeProtocol
    
    抛出:
    
    IOException
  - getBlockKeys
```
public ExportedBlockKeys getBlockKeys()
                               throws IOException
```
    Get the current block keys
    
    指定者:
    
    getBlockKeys 在接口中 NamenodeProtocol
    
    返回:
    ExportedBlockKeys containing current block keys
    
    抛出:
    
    IOException
  - errorReport
```
public void errorReport(DatanodeRegistration nodeReg,
               int errorCode,
               String msg)
                 throws IOException
```
    从接口复制的说明: DatanodeProtocol
    
    errorReport() tells the NameNode about something that has gone awry. Useful for debugging.
    
    指定者:
    
    errorReport 在接口中 DatanodeProtocol
    
    抛出:
    
    IOException
  - versionRequest
```
public NamespaceInfo versionRequest()
                             throws IOException
```
    指定者:
    
    versionRequest 在接口中 DatanodeProtocol
    
    抛出:
    
    IOException
  - processUpgradeCommand
```
public UpgradeCommand processUpgradeCommand(UpgradeCommand comm)
                                     throws IOException
```
    从接口复制的说明: DatanodeProtocol
    
    This is a very general way to send a command to the name-node during distributed upgrade process. The generosity is because the variety of upgrade commands is unpredictable. The reply from the name-node is also received in the form of an upgrade command.
    
    指定者:
    
    processUpgradeCommand 在接口中 DatanodeProtocol
    
    返回:
    a reply in the form of an upgrade command
    
    抛出:
    
    IOException
  - verifyRequest
```
public void verifyRequest(DatanodeRegistration nodeReg)
                   throws IOException
```
    Verify request. Verifies correctness of the datanode version, registration ID, and if the datanode does not need to be shutdown.
    
    参数:
    nodeReg - data node registration
    
    抛出:
    
    IOException
  - verifyVersion
```
public void verifyVersion(int version)
                   throws IOException
```
    Verify version.
    
    参数:
    version -
    
    抛出:
    
    IOException
  - getFsImageName
```
public File getFsImageName()
                    throws IOException
```
    Returns the name of the fsImage file
    
    抛出:
    
    IOException
  - getFSImage
```
public FSImage getFSImage()
```
  - getFsImageNameCheckpoint
```
public File[] getFsImageNameCheckpoint()
                                throws IOException
```
    Returns the name of the fsImage file uploaded by periodic checkpointing
    
    抛出:
    
    IOException
  - getNameNodeAddress
```
public InetSocketAddress getNameNodeAddress()
```
    Returns the address on which the NameNodes is listening to.
    
    返回:
    the address on which the NameNodes is listening to.
  - getHttpAddress
```
public InetSocketAddress getHttpAddress()
```
    Returns the address of the NameNodes http server, which is used to access the name-node web UI.
    
    返回:
    the http address.
  - refreshServiceAcl
```
public void refreshServiceAcl()
                       throws IOException
```
    从接口复制的说明: RefreshAuthorizationPolicyProtocol
    
    Refresh the service-level authorization policy in-effect.
    
    指定者:
    
    refreshServiceAcl 在接口中 RefreshAuthorizationPolicyProtocol
    
    抛出:
    
    IOException
  - refreshUserToGroupsMappings
```
public void refreshUserToGroupsMappings()
                                 throws IOException
```
    从接口复制的说明: RefreshUserMappingsProtocol
    
    Refresh user to group mappings.
    
    指定者:
    
    refreshUserToGroupsMappings 在接口中 RefreshUserMappingsProtocol
    
    抛出:
    
    IOException
  - refreshSuperUserGroupsConfiguration
```
public void refreshSuperUserGroupsConfiguration()
```
    从接口复制的说明: RefreshUserMappingsProtocol
    
    Refresh superuser proxy group list
    
    指定者:
    
    refreshSuperUserGroupsConfiguration 在接口中 RefreshUserMappingsProtocol
  - createNameNode
```
public static NameNode createNameNode(String[] argv,
                      Configuration conf)
                               throws IOException
```
    抛出:
    
    IOException
  - main
```
public static void main(String[] argv)
                 throws Exception
```
    抛出:
    
    Exception

类 NameNode

嵌套类概要

从接口继承的嵌套类/接口 org.apache.hadoop.hdfs.protocol.FSConstants

字段概要

从接口继承的字段 org.apache.hadoop.hdfs.protocol.ClientProtocol

从接口继承的字段 org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol

从接口继承的字段 org.apache.hadoop.hdfs.server.protocol.NamenodeProtocol

从接口继承的字段 org.apache.hadoop.hdfs.protocol.FSConstants

从接口继承的字段 org.apache.hadoop.security.authorize.RefreshAuthorizationPolicyProtocol

从接口继承的字段 org.apache.hadoop.security.RefreshUserMappingsProtocol

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

DEFAULT_PORT

LOG

stateChangeLog

serviceRPCAddress

构造器详细资料

NameNode

方法详细资料

getProtocolVersion

format

setNamesystem

getNamesystem

getNameNodeMetrics

getAddress

setServiceAddress

getServiceAddress

getAddress

getUri

getServiceRpcServerAddress

setRpcServiceServerAddress

getInfoServer

getHttpUriScheme

join

stop

getBlocks

getDelegationToken

renewDelegationToken

cancelDelegationToken

getBlockLocations

create

create

append

isFileClosed

recoverLease

setReplication

setPermission

setOwner

addBlock

addBlock

abandonBlock

complete

reportBadBlocks

nextGenerationStamp

commitBlockSynchronization

getPreferredBlockSize

concat

rename

delete

delete

mkdirs

renewLease

getListing

getFileInfo

getStats

getDatanodeReport

setSafeMode

Configuration parameters:

Special cases:

isInSafeMode

saveNamespace

refreshNodes

getEditLogSize

rollEditLog

rollFsImage

finalizeUpgrade

distributedUpgradeProgress

metaSave