org.apache.hadoop.hbase.master

Class RegionServerTracker

java.lang.Object

org.apache.hadoop.hbase.zookeeper.ZKListener

org.apache.hadoop.hbase.master.RegionServerTracker

@InterfaceAudience.Private
public class RegionServerTracker
extends ZKListener

Tracks the online region servers via ZK.

Handling of new RSs checking in is done via RPC. This class is only responsible for watching for expired nodes. It handles listening for changes in the RS node list. The only exception is when master restart, we will use the list fetched from zk to construct the initial set of live region servers.

If an RS node gets deleted, this automatically handles calling of ServerManager.expireServer(ServerName)

Field Summary

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZKListener

watcher

Constructor Summary

Constructors

Constructor and Description
RegionServerTracker(ZKWatcher watcher, MasterServices server)

Method Summary

Modifier and Type	Method and Description
Set<ServerName>	getRegionServers()
void	nodeChildrenChanged(String path)
void	stop()
void	upgrade(Set<ServerName> deadServersFromPE, Set<ServerName> liveServersBeforeRestart, Set<ServerName> splittingServersFromWALDir) Upgrade to active master mode, where besides tracking the changes of region server set, we will also started to add new region servers to ServerManager and also schedule SCP if a region server dies.

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZKListener

getWatcher, nodeCreated, nodeDataChanged, nodeDeleted

Methods inherited from class java.lang.Object

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

Constructor Detail

RegionServerTracker

public RegionServerTracker(ZKWatcher watcher,
                           MasterServices server)

Method Detail

upgrade

public void upgrade(Set<ServerName> deadServersFromPE,
                    Set<ServerName> liveServersBeforeRestart,
                    Set<ServerName> splittingServersFromWALDir)
             throws org.apache.zookeeper.KeeperException,
                    IOException

Upgrade to active master mode, where besides tracking the changes of region server set, we will also started to add new region servers to ServerManager and also schedule SCP if a region server dies. Starts the tracking of online RegionServers. All RSes will be tracked after this method is called.

In this method, we will also construct the region server sets in ServerManager. If a region server is dead between the crash of the previous master instance and the start of the current master instance, we will schedule a SCP for it. This is done in ServerManager.findDeadServersAndProcess(Set, Set), we call it here under the lock protection to prevent concurrency issues with server expiration operation.

Parameters:

deadServersFromPE - the region servers which already have SCP associated.

liveServersBeforeRestart - the live region servers we recorded before master restarts.

splittingServersFromWALDir - Servers whose WALs are being actively 'split'.

Throws:

org.apache.zookeeper.KeeperException

IOException

stop

public void stop()

getRegionServers

public Set<ServerName> getRegionServers()

nodeChildrenChanged

public void nodeChildrenChanged(String path)

Overrides:

nodeChildrenChanged in class ZKListener