org.apache.hadoop.hbase
Class HMaster

java.lang.Object
  java.lang.Thread
      org.apache.hadoop.hbase.HMaster

All Implemented Interfaces:

Runnable, HConstants, HMasterInterface, HMasterRegionInterface, VersionedProtocol

public class HMaster
extends Thread
implements HConstants, HMasterInterface, HMasterRegionInterface

HMaster is the "master server" for a HBase. There is only one HMaster for a single HBase deployment.

Nested Class Summary

static class

HMaster.MetaRegion Describes a meta region and its server

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

static String	MASTER Name of master server
protected Sleeper	sleeper

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Fields inherited from interface org.apache.hadoop.hbase.HConstants

ALL_META_COLUMNS, ALL_VERSIONS, COL_REGIONINFO, COL_REGIONINFO_ARRAY, COL_SERVER, COL_SPLITA, COL_SPLITB, COL_STARTCODE, COLUMN_FAMILY, COLUMN_FAMILY_ARRAY, COLUMN_FAMILY_STR, DEFAULT_HBASE_DIR, DEFAULT_HOST, DEFAULT_MASTER_ADDRESS, DEFAULT_MASTER_INFOPORT, DEFAULT_MASTER_PORT, DEFAULT_MAX_FILE_SIZE, DEFAULT_REGION_SERVER_CLASS, DEFAULT_REGIONSERVER_ADDRESS, DEFAULT_REGIONSERVER_INFOPORT, EMPTY_START_ROW, EMPTY_TEXT, FILE_SYSTEM_VERSION, HBASE_DIR, HREGION_LOGDIR_NAME, HREGION_OLDLOGFILE_NAME, LATEST_TIMESTAMP, MASTER_ADDRESS, META_TABLE_NAME, REGION_SERVER_CLASS, REGIONSERVER_ADDRESS, ROOT_TABLE_NAME, THREAD_WAKE_FREQUENCY, UTF8_ENCODING, VERSION_FILE_NAME

Fields inherited from interface org.apache.hadoop.hbase.HMasterInterface

versionID

Fields inherited from interface org.apache.hadoop.hbase.HMasterRegionInterface

versionID

Constructor Summary

HMaster(HBaseConfiguration conf)
Build the HMaster out of a raw configuration item.

HMaster(Path rootdir, HServerAddress address, HBaseConfiguration conf)
Build the HMaster

Method Summary

void	addColumn(Text tableName, HColumnDescriptor column) Adds a column to the specified table
protected boolean	checkFileSystem() Checks to see if the file system is still accessible.
protected HbaseMapWritable	createConfigurationSubset()
void	createTable(HTableDescriptor desc) Creates a new table
void	deleteColumn(Text tableName, Text columnName) Deletes a column from the specified table
void	deleteTable(Text tableName) Deletes a table
void	disableTable(Text tableName) Take table offline
protected static void	doMain(String[] args, Class<? extends HMaster> masterClass)
void	enableTable(Text tableName) Puts the table on-line (only needed if table has been previously taken offline)
HServerAddress	findRootRegion() Get the location of the root region
HBaseConfiguration	getConfiguration()
protected HRegionInfo	getHRegionInfo(Map<Text,byte[]> map)
HServerAddress	getMasterAddress()
Map<Text,HMaster.MetaRegion>	getOnlineMetaRegions()
long	getProtocolVersion(String protocol, long clientVersion) Return protocol version corresponding to protocol interface.
Path	getRootDir()
HServerAddress	getRootRegionLocation()
Map<String,HServerLoad>	getServersToLoad()
Map<String,HServerInfo>	getServersToServerInfo()
boolean	isMasterRunning()
static void	main(String[] args) Main program
void	modifyColumn(Text tableName, Text columnName, HColumnDescriptor descriptor) Modifies an existing column on the specified table
HMsg[]	regionServerReport(HServerInfo serverInfo, HMsg[] msgs) Called to renew lease, tell master what the region server is doing and to receive new instructions from the master
HbaseMapWritable	regionServerStartup(HServerInfo serverInfo) Called when a region server first starts
void	run() Main processing loop
void	shutdown() Shutdown an HBase cluster.
protected org.apache.hadoop.hbase.HMaster.RowMap	toRowMap(HbaseMapWritable mw)

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

sleeper

protected final Sleeper sleeper

MASTER

public static final String MASTER

Name of master server

See Also:

Constant Field Values

Constructor Detail

HMaster

public HMaster(HBaseConfiguration conf)
        throws IOException

Build the HMaster out of a raw configuration item.

Parameters:

conf - - Configuration object

Throws:

IOException

HMaster

public HMaster(Path rootdir,
               HServerAddress address,
               HBaseConfiguration conf)
        throws IOException

Build the HMaster

Parameters:

rootdir - base directory of this HBase instance

address - server address and port number

conf - configuration

Throws:

IOException

Method Detail

getProtocolVersion

public long getProtocolVersion(String protocol,
                               long clientVersion)
                        throws IOException

Return protocol version corresponding to protocol interface.

Specified by:

getProtocolVersion in interface VersionedProtocol

Parameters:

protocol - The classname of the protocol interface

clientVersion - The version of the protocol that the client speaks

Returns:

the version that the server will speak

Throws:

IOException

checkFileSystem

protected boolean checkFileSystem()

Checks to see if the file system is still accessible. If not, sets closed

Returns:

false if file system is not available

getMasterAddress

public HServerAddress getMasterAddress()

Returns:

HServerAddress of the master server

getRootDir

public Path getRootDir()

Returns:

Hbase root dir.

getServersToServerInfo

public Map<String,HServerInfo> getServersToServerInfo()

Returns:

Read-only map of servers to serverinfo.

getServersToLoad

public Map<String,HServerLoad> getServersToLoad()

Returns:

Read-only map of servers to load.

getRootRegionLocation

public HServerAddress getRootRegionLocation()

Returns:

Location of the -ROOT- region.

getOnlineMetaRegions

public Map<Text,HMaster.MetaRegion> getOnlineMetaRegions()

Returns:

Read-only map of online regions.

run

public void run()

Main processing loop

Specified by:

run in interface Runnable

Overrides:

run in class Thread

regionServerStartup

public HbaseMapWritable regionServerStartup(HServerInfo serverInfo)
                                     throws IOException

Called when a region server first starts

Specified by:

regionServerStartup in interface HMasterRegionInterface

Returns:

Configuration for the regionserver to use: e.g. filesystem, hbase rootdir, etc.

Throws:

IOException

createConfigurationSubset

protected HbaseMapWritable createConfigurationSubset()

Returns:

Subset of configuration to pass initializing regionservers: e.g. the filesystem to use and root directory to use.

regionServerReport

public HMsg[] regionServerReport(HServerInfo serverInfo,
                                 HMsg[] msgs)
                          throws IOException

Called to renew lease, tell master what the region server is doing and to receive new instructions from the master

Specified by:

regionServerReport in interface HMasterRegionInterface

Parameters:

serverInfo - server's address and start code

msgs - things the region server wants to tell the master

Returns:

instructions from the master to the region server

Throws:

IOException

isMasterRunning

public boolean isMasterRunning()

Specified by:

isMasterRunning in interface HMasterInterface

Returns:

true if master is available

shutdown

public void shutdown()

Shutdown an HBase cluster.

Specified by:

shutdown in interface HMasterInterface

createTable

public void createTable(HTableDescriptor desc)
                 throws IOException

Creates a new table

Specified by:

createTable in interface HMasterInterface

Parameters:

desc - table descriptor

Throws:

IOException

deleteTable

public void deleteTable(Text tableName)
                 throws IOException

Deletes a table

Specified by:

deleteTable in interface HMasterInterface

Throws:

IOException

addColumn

public void addColumn(Text tableName,
                      HColumnDescriptor column)
               throws IOException

Adds a column to the specified table

Specified by:

addColumn in interface HMasterInterface

column - column descriptor

Throws:

IOException

modifyColumn

public void modifyColumn(Text tableName,
                         Text columnName,
                         HColumnDescriptor descriptor)
                  throws IOException

Modifies an existing column on the specified table

Specified by:

modifyColumn in interface HMasterInterface

columnName - name of the column to edit

descriptor - new column descriptor

Throws:

IOException

deleteColumn

public void deleteColumn(Text tableName,
                         Text columnName)
                  throws IOException

Deletes a column from the specified table

Specified by:

deleteColumn in interface HMasterInterface

Throws:

IOException

enableTable

public void enableTable(Text tableName)
                 throws IOException

Puts the table on-line (only needed if table has been previously taken offline)

Specified by:

enableTable in interface HMasterInterface

Throws:

IOException

disableTable

public void disableTable(Text tableName)
                  throws IOException

Take table offline

Specified by:

disableTable in interface HMasterInterface

Throws:

IOException

findRootRegion

public HServerAddress findRootRegion()

Get the location of the root region

Specified by:

findRootRegion in interface HMasterInterface

Returns:

address of server that serves the root region

getConfiguration

public HBaseConfiguration getConfiguration()

Returns:

Return configuration being used by this server.

toRowMap

protected org.apache.hadoop.hbase.HMaster.RowMap toRowMap(HbaseMapWritable mw)

getHRegionInfo

protected HRegionInfo getHRegionInfo(Map<Text,byte[]> map)
                              throws IOException

Throws:

IOException

doMain

protected static void doMain(String[] args,
                             Class<? extends HMaster> masterClass)

main

public static void main(String[] args)

Main program

Parameters:

args -