Package org.apache.hadoop.hdfs.server.federation.resolver.order

Class LeaderFollowerResolver

java.lang.Object

org.apache.hadoop.hdfs.server.federation.resolver.order.LeaderFollowerResolver

All Implemented Interfaces:

OrderedResolver

public class LeaderFollowerResolver
extends Object
implements OrderedResolver

LEADER_FOLLOWER can be used in cross-cluster disaster tolerance, and the order of namespaces is always "leader,follower,follower...". Write data in leader sub-cluster as many as possible. If leader sub-cluster failed, try followers then, the same goes for reading data.

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor	Description
LeaderFollowerResolver()

Method Summary

Modifier and Type	Method	Description
String	getFirstNamespace(String path, PathLocation loc)	Get the first namespace based on this resolver approach.

Methods inherited from class java.lang.Object

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

Field Details

LOG

protected static final org.slf4j.Logger LOG

Constructor Details

LeaderFollowerResolver

public LeaderFollowerResolver()

Method Details

getFirstNamespace

public String getFirstNamespace(String path,
 PathLocation loc)

Description copied from interface: OrderedResolver

Get the first namespace based on this resolver approach.

Specified by:

getFirstNamespace in interface OrderedResolver

Parameters:

path - Path to check.

loc - Federated location with multiple destinations.

Returns:

First namespace out of the locations.