org.apache.hadoop.hbase.master

Class ServerManager

java.lang.Object

org.apache.hadoop.hbase.master.ServerManager

@InterfaceAudience.Private
public class ServerManager
extends Object

The ServerManager class manages info about region servers.

Maintains lists of online and dead servers. Processes the startups, shutdowns, and deaths of region servers.

Servers are distinguished in two different ways. A given server has a location, specified by hostname and port, and of which there can only be one online at any given time. A server instance is specified by the location (hostname and port) as well as the startcode (timestamp from when the server was started). This is used to differentiate a restarted instance of a given server from the original instance.

If a sever is known not to be running any more, it is called dead. The dead server needs to be handled by a ServerShutdownHandler. If the handler is not enabled yet, the server can't be handled right away so it is queued up. After the handler is enabled, the server will be submitted to a handler to handle. However, the handler may be just partially enabled. If so, the server cannot be fully processed, and be queued up for further processing. A server is fully processed only after the handler is fully enabled and has completed the handling.

Field Summary

Fields

Modifier and Type	Field and Description
static String	WAIT_ON_REGIONSERVERS_INTERVAL
static String	WAIT_ON_REGIONSERVERS_MAXTOSTART
static String	WAIT_ON_REGIONSERVERS_MINTOSTART
static String	WAIT_ON_REGIONSERVERS_TIMEOUT

Constructor Summary

Constructors

Constructor and Description
ServerManager(MasterServices master) Constructor.

Method Summary

Modifier and Type	Method and Description
boolean	addServerToDrainList(ServerName sn) Add the server to the drain list.
boolean	areDeadServersInProgress() Checks if any dead servers are currently in progress.
static void	closeRegionSilentlyAndWait(ClusterConnection connection, ServerName server, RegionInfo region, long timeout) Contacts a region server and waits up to timeout ms to close the region.
int	countOfRegionServers()
List<ServerName>	createDestinationServersList() Calls createDestinationServersList(java.util.List<org.apache.hadoop.hbase.ServerName>) without server to exclude.
List<ServerName>	createDestinationServersList(List<ServerName> serversToExclude) Creates a list of possible destinations for a region.
boolean	expireServer(ServerName serverName) Expire the passed server.
double	getAverageLoad() Compute the average load across all region servers.
DeadServer	getDeadServers()
List<ServerName>	getDrainingServersList()
int	getInfoPort(ServerName serverName)
ClusterStatusProtos.RegionStoreSequenceIds	getLastFlushedSequenceId(byte[] encodedRegionName)
ServerMetrics	getLoad(ServerName serverName)
Map<ServerName,ServerMetrics>	getOnlineServers()
List<ServerName>	getOnlineServersList()
List<ServerName>	getOnlineServersListWithPredicator(List<ServerName> keys, Predicate<ServerMetrics> idleServerPredicator)
AdminProtos.AdminService.BlockingInterface	getRsAdmin(ServerName sn)
String	getVersion(ServerName serverName) May return "0.0.0" when server is not online
int	getVersionNumber(ServerName serverName) May return 0 when server is not online.
boolean	isClusterShutdown()
boolean	isRegionInServerManagerStates(RegionInfo hri)
boolean	isServerDead(ServerName serverName) Check if a server is known to be dead.
boolean	isServerOnline(ServerName serverName)
boolean	moveFromOnlineToDeadServers(ServerName sn)
void	regionServerReport(ServerName sn, ServerMetrics sl)
void	registerListener(ServerListener listener) Add the listener to the notification list.
void	removeRegion(RegionInfo regionInfo) Called by delete table and similar to notify the ServerManager that a region was removed.
void	removeRegions(List<RegionInfo> regions) Called by delete table and similar to notify the ServerManager that a region was removed.
boolean	removeServerFromDrainList(ServerName sn)
void	sendRegionWarmup(ServerName server, RegionInfo region) Sends a WARMUP RPC to the specified server to warmup the specified region.
void	shutdownCluster()
void	stop() Stop the ServerManager.
boolean	unregisterListener(ServerListener listener) Remove the listener from the notification list.
void	waitForRegionServers(MonitoredTask status) Wait for the region servers to report in.

Methods inherited from class java.lang.Object

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

Field Detail

WAIT_ON_REGIONSERVERS_MAXTOSTART

public static final String WAIT_ON_REGIONSERVERS_MAXTOSTART

See Also:

Constant Field Values

WAIT_ON_REGIONSERVERS_MINTOSTART

public static final String WAIT_ON_REGIONSERVERS_MINTOSTART

See Also:

Constant Field Values

WAIT_ON_REGIONSERVERS_TIMEOUT

public static final String WAIT_ON_REGIONSERVERS_TIMEOUT

See Also:

Constant Field Values

WAIT_ON_REGIONSERVERS_INTERVAL

public static final String WAIT_ON_REGIONSERVERS_INTERVAL

See Also:

Constant Field Values

Constructor Detail

ServerManager

public ServerManager(MasterServices master)

Constructor.

Method Detail

registerListener

public void registerListener(ServerListener listener)

Add the listener to the notification list.

Parameters:

listener - The ServerListener to register

unregisterListener

public boolean unregisterListener(ServerListener listener)

Remove the listener from the notification list.

Parameters:

listener - The ServerListener to unregister

regionServerReport

public void regionServerReport(ServerName sn,
                               ServerMetrics sl)
                        throws YouAreDeadException

Throws:

YouAreDeadException

getLastFlushedSequenceId

public ClusterStatusProtos.RegionStoreSequenceIds getLastFlushedSequenceId(byte[] encodedRegionName)

getLoad

public ServerMetrics getLoad(ServerName serverName)

Parameters:

serverName -

Returns:

ServerMetrics if serverName is known else null

getAverageLoad

public double getAverageLoad()

Compute the average load across all region servers. Currently, this uses a very naive computation - just uses the number of regions being served, ignoring stats about number of requests.

Returns:

the average load

countOfRegionServers

public int countOfRegionServers()

Returns:

the count of active regionservers

getOnlineServers

public Map<ServerName,ServerMetrics> getOnlineServers()

Returns:

Read-only map of servers to serverinfo

getDeadServers

public DeadServer getDeadServers()

areDeadServersInProgress

public boolean areDeadServersInProgress()

Checks if any dead servers are currently in progress.

Returns:

true if any RS are being processed as dead, false if not

expireServer

public boolean expireServer(ServerName serverName)

Expire the passed server. Add it to list of dead servers and queue a shutdown processing.

Returns:

True if we queued a ServerCrashProcedure else false if we did not (could happen for many reasons including the fact that its this server that is going down or we already have queued an SCP for this server or SCP processing is currently disabled because we are in startup phase).

moveFromOnlineToDeadServers

public boolean moveFromOnlineToDeadServers(ServerName sn)

Returns:

Returns true if was online.

removeServerFromDrainList

public boolean removeServerFromDrainList(ServerName sn)

addServerToDrainList

public boolean addServerToDrainList(ServerName sn)

Add the server to the drain list.

Parameters:

sn -

Returns:

True if the server is added or the server is already on the drain list.

sendRegionWarmup

public void sendRegionWarmup(ServerName server,
                             RegionInfo region)

Sends a WARMUP RPC to the specified server to warmup the specified region.

A region server could reject the close request because it either does not have the specified region or the region is being split.

Parameters:

server - server to warmup a region

region - region to warmup

closeRegionSilentlyAndWait

public static void closeRegionSilentlyAndWait(ClusterConnection connection,
                                              ServerName server,
                                              RegionInfo region,
                                              long timeout)
                                       throws IOException,
                                              InterruptedException

Contacts a region server and waits up to timeout ms to close the region. This bypasses the active hmaster.

Throws:

IOException

InterruptedException

getRsAdmin

public AdminProtos.AdminService.BlockingInterface getRsAdmin(ServerName sn)
                                                      throws IOException

Parameters:

sn -

Returns:

Admin interface for the remote regionserver named sn

Throws:

IOException

RetriesExhaustedException - wrapping a ConnectException if failed

waitForRegionServers

public void waitForRegionServers(MonitoredTask status)
                          throws InterruptedException

Wait for the region servers to report in. We will wait until one of this condition is met: - the master is stopped - the 'hbase.master.wait.on.regionservers.maxtostart' number of region servers is reached - the 'hbase.master.wait.on.regionservers.mintostart' is reached AND there have been no new region server in for 'hbase.master.wait.on.regionservers.interval' time AND the 'hbase.master.wait.on.regionservers.timeout' is reached

Throws:

InterruptedException

getOnlineServersList

public List<ServerName> getOnlineServersList()

Returns:

A copy of the internal list of online servers.

getOnlineServersListWithPredicator

public List<ServerName> getOnlineServersListWithPredicator(List<ServerName> keys,
                                                           Predicate<ServerMetrics> idleServerPredicator)

Parameters:

keys - The target server name

idleServerPredicator - Evaluates the server on the given load

Returns:

A copy of the internal list of online servers matched by the predicator

getDrainingServersList

public List<ServerName> getDrainingServersList()

Returns:

A copy of the internal list of draining servers.

isServerOnline

public boolean isServerOnline(ServerName serverName)

isServerDead

public boolean isServerDead(ServerName serverName)

Check if a server is known to be dead. A server can be online, or known to be dead, or unknown to this manager (i.e, not online, not known to be dead either. it is simply not tracked by the master any more, for example, a very old previous instance).

shutdownCluster

public void shutdownCluster()

isClusterShutdown

public boolean isClusterShutdown()

stop

public void stop()

Stop the ServerManager.

createDestinationServersList

public List<ServerName> createDestinationServersList(List<ServerName> serversToExclude)

Creates a list of possible destinations for a region. It contains the online servers, but not the draining or dying servers.

Parameters:

serversToExclude - can be null if there is no server to exclude

createDestinationServersList

public List<ServerName> createDestinationServersList()

Calls createDestinationServersList(java.util.List<org.apache.hadoop.hbase.ServerName>) without server to exclude.

removeRegion

public void removeRegion(RegionInfo regionInfo)

Called by delete table and similar to notify the ServerManager that a region was removed.

isRegionInServerManagerStates

public boolean isRegionInServerManagerStates(RegionInfo hri)

removeRegions

public void removeRegions(List<RegionInfo> regions)

Called by delete table and similar to notify the ServerManager that a region was removed.

getVersionNumber

public int getVersionNumber(ServerName serverName)

May return 0 when server is not online.

getVersion

public String getVersion(ServerName serverName)

May return "0.0.0" when server is not online

getInfoPort

public int getInfoPort(ServerName serverName)