edu.iu.dsc.tws.common.zk

Class ZKJobMasterRegistrar

java.lang.Object

edu.iu.dsc.tws.common.zk.ZKJobMasterRegistrar

public class ZKJobMasterRegistrar
extends java.lang.Object

it is a single node controller A single node registers, others discover that node In our case, Job Master registers, workers discover the job master Job Master creates an eph persistent znode Job Master IP and port number is put as the payload to this node in the form of: <ip>:<port> the node must be deleted after the job completes

Constructor Summary

Constructors

Constructor and Description
ZKJobMasterRegistrar(Config config, java.lang.String jobMasterIP, int jobMasterPort, java.lang.String jobID)

Method Summary

Modifier and Type	Method and Description
void	close()
static java.lang.String	constructJobMasterPath(Config config, java.lang.String jobID) construct job master path
void	deleteJobMasterZNode() this method can be used to delete the znode from a previous session if you don't want to wait the ZooKeeper to delete the ephemeral znode if ZKJobMasterRegistrar is not closed properly in the previous session, it takes around 30 seconds for ZooKeeper to delete the ephemeral JobMaster node
boolean	initialize() connect to ZooKeeper server
boolean	sameZNodeExist() check whether there is already the same node on ZooKeeper server this can happen when the JobMasterRegistrar is not properly closed and it is started again immediately.

Methods inherited from class java.lang.Object

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

Constructor Detail

ZKJobMasterRegistrar

public ZKJobMasterRegistrar(Config config,
                            java.lang.String jobMasterIP,
                            int jobMasterPort,
                            java.lang.String jobID)

Method Detail

constructJobMasterPath

public static java.lang.String constructJobMasterPath(Config config,
                                                      java.lang.String jobID)

construct job master path

initialize

public boolean initialize()

connect to ZooKeeper server

sameZNodeExist

public boolean sameZNodeExist()

check whether there is already the same node on ZooKeeper server this can happen when the JobMasterRegistrar is not properly closed and it is started again immediately. ZooKeeper takes around 30 seconds to delete ephemeral znodes in those cases During this time, if JobMasterRegistrar restarts with the same job name, this can happen

deleteJobMasterZNode

public void deleteJobMasterZNode()

this method can be used to delete the znode from a previous session if you don't want to wait the ZooKeeper to delete the ephemeral znode if ZKJobMasterRegistrar is not closed properly in the previous session, it takes around 30 seconds for ZooKeeper to delete the ephemeral JobMaster node

close

public void close()