Package org.apache.hadoop.hdfs.client.impl

Class LeaseRenewer

java.lang.Object

org.apache.hadoop.hdfs.client.impl.LeaseRenewer

@Private
public class LeaseRenewer
extends Object

Used by DFSClient for renewing file-being-written leases on the namenode. When a file is opened for write (create or append), namenode stores a file lease for recording the identity of the writer. The writer (i.e. the DFSClient) is required to renew the lease periodically. When the lease is not renewed before it expires, the namenode considers the writer as failed and then it may either let another writer to obtain the lease or close the file.

This class also provides the following functionality:

• It maintains a map from (namenode, user) pairs to lease renewers. The same LeaseRenewer instance is used for renewing lease for all the DFSClient to the same namenode and the same user.
• Each renewer maintains a list of DFSClient. Periodically the leases for all the clients are renewed. A client is removed from the list when the client is closed.
• A thread per namenode per user is used by the LeaseRenewer to renew the leases.

Field Summary

Fields

Modifier and Type	Field	Description
static final org.slf4j.Logger	LOG

Method Summary

Modifier and Type	Method	Description
void	closeClient(DFSClient dfsc)	Close the given client.
static LeaseRenewer	getInstance(String authority, org.apache.hadoop.security.UserGroupInformation ugi, DFSClient dfsc)	Get a LeaseRenewer instance
void	interruptAndJoin()
boolean	isEmpty()	Does this renewer have nothing to renew?
boolean	isRunning()
boolean	put(DFSClient dfsc)
static void	remove(LeaseRenewer renewer)	Remove the given renewer from the Factory.
static void	setLeaseRenewerGraceDefault(long leaseRenewerGraceDefault)
void	setRenewalTime(long renewal)	Used for testing only.
String	toString()

Methods inherited from class java.lang.Object

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

Field Details

LOG

public static final org.slf4j.Logger LOG

Method Details

getInstance

public static LeaseRenewer getInstance(String authority,
 org.apache.hadoop.security.UserGroupInformation ugi,
 DFSClient dfsc)

Get a LeaseRenewer instance

remove

public static void remove(LeaseRenewer renewer)

Remove the given renewer from the Factory. Subsequent call will receive new LeaseRenewer instance.

Parameters:

renewer - Instance to be cleared from Factory

setRenewalTime

@VisibleForTesting
public void setRenewalTime(long renewal)

Used for testing only.

isRunning

@VisibleForTesting
public boolean isRunning()

isEmpty

public boolean isEmpty()

Does this renewer have nothing to renew?

put

public boolean put(DFSClient dfsc)

closeClient

public void closeClient(DFSClient dfsc)

Close the given client.

interruptAndJoin

public void interruptAndJoin()
                      throws InterruptedException

Throws:

InterruptedException

toString

public String toString()

Overrides:

toString in class Object

setLeaseRenewerGraceDefault

@VisibleForTesting
public static void setLeaseRenewerGraceDefault(long leaseRenewerGraceDefault)