org.apache.spark.storage

Class FileBasedTopologyMapper

Object

org.apache.spark.storage.TopologyMapper

org.apache.spark.storage.FileBasedTopologyMapper

public class FileBasedTopologyMapper
extends TopologyMapper

A simple file based topology mapper. This expects topology information provided as a Properties file. The name of the file is obtained from SparkConf property spark.storage.replication.topologyFile. To use this topology mapper, set the spark.storage.replication.topologyMapper property to FileBasedTopologyMapper param: conf SparkConf object

Constructor Summary

Constructors

Constructor and Description
FileBasedTopologyMapper(SparkConf conf)

Method Summary

Methods

Modifier and Type	Method and Description
scala.Option<String>	getTopologyForHost(String hostname) Gets the topology information given the host name
scala.Option<String>	topologyFile()
scala.collection.Map<String,String>	topologyMap()

Methods inherited from class Object

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

Constructor Detail

FileBasedTopologyMapper

public FileBasedTopologyMapper(SparkConf conf)

Method Detail

topologyFile

public scala.Option<String> topologyFile()

topologyMap

public scala.collection.Map<String,String> topologyMap()

getTopologyForHost

public scala.Option<String> getTopologyForHost(String hostname)

Description copied from class: TopologyMapper

Gets the topology information given the host name

Specified by:

getTopologyForHost in class TopologyMapper

Parameters:

hostname - Hostname

Returns:

topology information for the given hostname. One can use a 'topology delimiter' to make this topology information nested. For example : ‘/myrack/myhost’, where ‘/’ is the topology delimiter, ‘myrack’ is the topology identifier, and ‘myhost’ is the individual host. This function only returns the topology information without the hostname. This information can be used when choosing executors for block replication to discern executors from a different rack than a candidate executor, for example.

An implementation can choose to use empty strings or None in case topology info is not available. This would imply that all such executors belong to the same rack.