org.apache.hadoop.hbase.ipc
Interface HMasterInterface

All Superinterfaces:

HBaseRPCProtocolVersion, org.apache.hadoop.ipc.VersionedProtocol

All Known Implementing Classes:

HMaster, HMasterCommandLine.LocalHMaster

public interface HMasterInterface
extends HBaseRPCProtocolVersion

Clients interact with the HMasterInterface to gain access to meta-level HBase functionality, like finding an HRegionServer and creating/destroying tables.

NOTE: if you change the interface, you must change the RPC version number in HBaseRPCProtocolVersion

Field Summary

Fields inherited from interface org.apache.hadoop.hbase.ipc.HBaseRPCProtocolVersion

versionID

Method Summary

void	addColumn(byte[] tableName, HColumnDescriptor column) Adds a column to the specified table
void	assign(byte[] regionName, boolean force) Assign a region to a server chosen at random.
boolean	balance() Run the balancer.
boolean	balanceSwitch(boolean b) Turn the load balancer on or off.
void	createTable(HTableDescriptor desc, byte[][] splitKeys) Creates a new table.
void	deleteColumn(byte[] tableName, byte[] columnName) Deletes a column from the specified table.
void	deleteTable(byte[] tableName) Deletes a table
void	disableTable(byte[] tableName) Take table offline
void	enableTable(byte[] tableName) Puts the table on-line (only needed if table has been previously taken offline)
ClusterStatus	getClusterStatus() Return cluster status.
boolean	isMasterRunning()
void	modifyColumn(byte[] tableName, HColumnDescriptor descriptor) Modifies an existing column on the specified table
void	modifyTable(byte[] tableName, HTableDescriptor htd) Modify a table's metadata
void	move(byte[] encodedRegionName, byte[] destServerName) Move the region r to dest.
void	shutdown() Shutdown an HBase cluster.
void	stopMaster() Stop HBase Master only.
void	unassign(byte[] regionName, boolean force) Unassign a region from current hosting regionserver.

Methods inherited from interface org.apache.hadoop.ipc.VersionedProtocol

getProtocolVersion

Method Detail

isMasterRunning

boolean isMasterRunning()

Returns:

true if master is available

createTable

void createTable(HTableDescriptor desc,
                 byte[][] splitKeys)
                 throws java.io.IOException

Creates a new table. If splitKeys are specified, then the table will be created with an initial set of multiple regions. If splitKeys is null, the table will be created with a single region.

Parameters:

desc - table descriptor

splitKeys -

Throws:

java.io.IOException

deleteTable

void deleteTable(byte[] tableName)
                 throws java.io.IOException

Deletes a table

Parameters:

tableName - table to delete

Throws:

java.io.IOException - e

addColumn

void addColumn(byte[] tableName,
               HColumnDescriptor column)
               throws java.io.IOException

Adds a column to the specified table

Parameters:

tableName - table to modify

column - column descriptor

Throws:

java.io.IOException - e

modifyColumn

void modifyColumn(byte[] tableName,
                  HColumnDescriptor descriptor)
                  throws java.io.IOException

Modifies an existing column on the specified table

Parameters:

tableName - table name

descriptor - new column descriptor

Throws:

java.io.IOException - e

deleteColumn

void deleteColumn(byte[] tableName,
                  byte[] columnName)
                  throws java.io.IOException

Deletes a column from the specified table. Table must be disabled.

Parameters:

tableName - table to alter

columnName - column family to remove

Throws:

java.io.IOException - e

enableTable

void enableTable(byte[] tableName)
                 throws java.io.IOException

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

Parameters:

tableName - table to enable

Throws:

java.io.IOException - e

disableTable

void disableTable(byte[] tableName)
                  throws java.io.IOException

Take table offline

Parameters:

tableName - table to take offline

Throws:

java.io.IOException - e

modifyTable

void modifyTable(byte[] tableName,
                 HTableDescriptor htd)
                 throws java.io.IOException

Modify a table's metadata

Parameters:

tableName - table to modify

htd - new descriptor for table

Throws:

java.io.IOException - e

shutdown

void shutdown()
              throws java.io.IOException

Shutdown an HBase cluster.

Throws:

java.io.IOException - e

stopMaster

void stopMaster()
                throws java.io.IOException

Stop HBase Master only. Does not shutdown the cluster.

Throws:

java.io.IOException - e

getClusterStatus

ClusterStatus getClusterStatus()

Return cluster status.

Returns:

status object

move

void move(byte[] encodedRegionName,
          byte[] destServerName)
          throws UnknownRegionException

Move the region r to dest.

Parameters:

encodedRegionName - The encoded region name; i.e. the hash that makes up the region name suffix: e.g. if regionname is TestTable,0094429456,1289497600452.527db22f95c8a9e0116f0cc13c680396., then the encoded region name is: 527db22f95c8a9e0116f0cc13c680396.

destServerName - The servername of the destination regionserver. If passed the empty byte array we'll assign to a random server. A server name is made of host, port and startcode. Here is an example: host187.example.com,60020,1289493121758.

Throws:

UnknownRegionException - Thrown if we can't find a region named encodedRegionName

assign

void assign(byte[] regionName,
            boolean force)
            throws java.io.IOException

Assign a region to a server chosen at random.

Parameters:

regionName - Region to assign. Will use existing RegionPlan if one found.

force - If true, will force the assignment.

Throws:

java.io.IOException

unassign

void unassign(byte[] regionName,
              boolean force)
              throws java.io.IOException

Unassign a region from current hosting regionserver. Region will then be assigned to a regionserver chosen at random. Region could be reassigned back to the same server. Use move(byte[], byte[]) if you want to control the region movement.

Parameters:

regionName - Region to unassign. Will clear any existing RegionPlan if one found.

force - If true, force unassign (Will remove region from regions-in-transition too if present).

Throws:

java.io.IOException

balance

boolean balance()

Run the balancer. Will run the balancer and if regions to move, it will go ahead and do the reassignments. Can NOT run for various reasons. Check logs.

Returns:

True if balancer ran, false otherwise.

balanceSwitch

boolean balanceSwitch(boolean b)

Turn the load balancer on or off.

Parameters:

b - If true, enable balancer. If false, disable balancer.

Returns:

Previous balancer value