org.apache.hadoop.hbase.master

Class DeadServer

java.lang.Object

org.apache.hadoop.hbase.master.DeadServer

@InterfaceAudience.Private
public class DeadServer
extends Object

Class to hold dead servers list and utility querying dead server list. On znode expiration, servers are added here.

Field Summary

Fields

Modifier and Type	Field and Description
private Map<ServerName,Long>	deadServers Set of known dead servers.
private static org.slf4j.Logger	LOG
private Set<ServerName>	processingServers Set of dead servers currently being processed
private static Comparator<Pair<ServerName,Long>>	ServerNameDeathDateComparator

Constructor Summary

Constructors

Constructor and Description
DeadServer()

Method Summary

Modifier and Type	Method and Description
void	add(ServerName sn) Adds the server to the dead server list if it's not there already.
boolean	areDeadServersInProgress() Checks if there are currently any dead servers being processed by the master.
void	cleanAllPreviousInstances(ServerName newServerName)
boolean	cleanPreviousInstance(ServerName newServerName) A dead server that comes back alive has a different start code.
List<Pair<ServerName,Long>>	copyDeadServersSince(long ts) Extract all the servers dead since a given time, and sort them.
Set<ServerName>	copyServerNames()
void	finish(ServerName sn) Complete processing for this dead server.
Date	getTimeOfDeath(ServerName deadServerName) Get the time when a server died
boolean	isDeadServer(ServerName serverName)
boolean	isEmpty()
boolean	isProcessingServer(ServerName serverName)
void	notifyServer(ServerName sn) Notify that we started processing this dead server.
boolean	removeDeadServer(ServerName deadServerName) remove the specified dead server
int	size()
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final org.slf4j.Logger LOG

deadServers

private final Map<ServerName,Long> deadServers

Set of known dead servers. On znode expiration, servers are added here. This is needed in case of a network partitioning where the server's lease expires, but the server is still running. After the network is healed, and it's server logs are recovered, it will be told to call server startup because by then, its regions have probably been reassigned.

processingServers

private final Set<ServerName> processingServers

Set of dead servers currently being processed

ServerNameDeathDateComparator

private static Comparator<Pair<ServerName,Long>> ServerNameDeathDateComparator

Constructor Detail

DeadServer

public DeadServer()

Method Detail

cleanPreviousInstance

public boolean cleanPreviousInstance(ServerName newServerName)

A dead server that comes back alive has a different start code. The new start code should be greater than the old one, but we don't take this into account in this method.

Parameters:

newServerName - Servername as either host:port or host,port,startcode.

Returns:

true if this server was dead before and coming back alive again

isDeadServer

public boolean isDeadServer(ServerName serverName)

Parameters:

serverName - server name.

Returns:

true if this server is on the dead servers list false otherwise

isProcessingServer

public boolean isProcessingServer(ServerName serverName)

Parameters:

serverName - server name.

Returns:

true if this server is on the processing servers list false otherwise

areDeadServersInProgress

public boolean areDeadServersInProgress()

Checks if there are currently any dead servers being processed by the master. Returns true if at least one region server is currently being processed as dead.

Returns:

true if any RS are being processed as dead

copyServerNames

public Set<ServerName> copyServerNames()

add

public void add(ServerName sn)

Adds the server to the dead server list if it's not there already.

Parameters:

sn - the server name

notifyServer

public void notifyServer(ServerName sn)

Notify that we started processing this dead server.

Parameters:

sn - ServerName for the dead server.

finish

public void finish(ServerName sn)

Complete processing for this dead server.

Parameters:

sn - ServerName for the dead server.

size

public int size()

isEmpty

public boolean isEmpty()

cleanAllPreviousInstances

public void cleanAllPreviousInstances(ServerName newServerName)

toString

public String toString()

Overrides:

toString in class Object

copyDeadServersSince

public List<Pair<ServerName,Long>> copyDeadServersSince(long ts)

Extract all the servers dead since a given time, and sort them.

Parameters:

ts - the time, 0 for all

Returns:

a sorted array list, by death time, lowest values first.

getTimeOfDeath

public Date getTimeOfDeath(ServerName deadServerName)

Get the time when a server died

Parameters:

deadServerName - the dead server name

Returns:

the date when the server died

removeDeadServer

public boolean removeDeadServer(ServerName deadServerName)

remove the specified dead server

Parameters:

deadServerName - the dead server name

Returns:

true if this server was removed