alluxio.client.file.dora

Class LocalWorkerPolicy

java.lang.Object

alluxio.client.file.dora.LocalWorkerPolicy

All Implemented Interfaces:

WorkerLocationPolicy

public class LocalWorkerPolicy
extends Object
implements WorkerLocationPolicy

A policy where a client will ONLY talk to a local worker. This policy can probably only be used in testing. If client on node A reads path /a, it will only talk to the worker on node A and produce a cache there. If a client on node B reads the same path /a, it will not see the cache on node A. A use case for this policy is a test like StressWorkerBench, where we create clients (with job service) and simulate I/O workload to workers. If all clients talk to their local worker, the test creates balanced stress on each worker and we measure local read performance.

Nested Class Summary

Nested classes/interfaces inherited from interface alluxio.client.file.dora.WorkerLocationPolicy

WorkerLocationPolicy.Factory

Constructor Summary

Constructors

Constructor and Description
LocalWorkerPolicy(AlluxioConfiguration conf) Constructs a new LocalWorkerPolicy.

Method Summary

Modifier and Type	Method and Description
List<BlockWorkerInfo>	getPreferredWorkers(List<BlockWorkerInfo> blockWorkerInfos, String fileId, int count) Finds a local worker from the available workers, matching by hostname.

Methods inherited from class java.lang.Object

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

Constructor Detail

LocalWorkerPolicy

public LocalWorkerPolicy(AlluxioConfiguration conf)

Constructs a new LocalWorkerPolicy.

Parameters:

conf - the configuration used by the policy

Method Detail

getPreferredWorkers

public List<BlockWorkerInfo> getPreferredWorkers(List<BlockWorkerInfo> blockWorkerInfos,
                                                 String fileId,
                                                 int count)
                                          throws ResourceExhaustedException

Finds a local worker from the available workers, matching by hostname. If there are multiple workers matching the client hostname, return the 1st one following the input order.

Specified by:

getPreferredWorkers in interface WorkerLocationPolicy

Returns:

a list of preferred workers

Throws:

ResourceExhaustedException - if unable to return exactly #{count} workers