org.apache.bookkeeper.client

Interface EnsemblePlacementPolicy

All Known Implementing Classes:

DefaultEnsemblePlacementPolicy, RackawareEnsemblePlacementPolicy

public interface EnsemblePlacementPolicy

Encapsulation of the algorithm that selects a number of bookies from the cluster as an ensemble for storing data, based on the data input as well as the node properties.

Method Summary

Methods

Modifier and Type	Method and Description
EnsemblePlacementPolicy	initialize(org.apache.commons.configuration.Configuration conf) Initialize the policy.
ArrayList<org.apache.bookkeeper.net.BookieSocketAddress>	newEnsemble(int ensembleSize, int writeQuorumSize, Set<org.apache.bookkeeper.net.BookieSocketAddress> excludeBookies) Choose numBookies bookies for ensemble.
Set<org.apache.bookkeeper.net.BookieSocketAddress>	onClusterChanged(Set<org.apache.bookkeeper.net.BookieSocketAddress> writableBookies, Set<org.apache.bookkeeper.net.BookieSocketAddress> readOnlyBookies) A consistent view of the cluster (what bookies are available as writable, what bookies are available as readonly) is updated when any changes happen in the cluster.
org.apache.bookkeeper.net.BookieSocketAddress	replaceBookie(org.apache.bookkeeper.net.BookieSocketAddress bookieToReplace, Set<org.apache.bookkeeper.net.BookieSocketAddress> excludeBookies) Choose a new bookie to replace bookieToReplace.
void	uninitalize() Uninitialize the policy

Method Detail

initialize

EnsemblePlacementPolicy initialize(org.apache.commons.configuration.Configuration conf)

Initialize the policy.

Parameters:

conf - client configuration.

Returns:

initialized ensemble placement policy

uninitalize

void uninitalize()

Uninitialize the policy

onClusterChanged

Set<org.apache.bookkeeper.net.BookieSocketAddress> onClusterChanged(Set<org.apache.bookkeeper.net.BookieSocketAddress> writableBookies,
                                                                  Set<org.apache.bookkeeper.net.BookieSocketAddress> readOnlyBookies)

A consistent view of the cluster (what bookies are available as writable, what bookies are available as readonly) is updated when any changes happen in the cluster.

Parameters:

writableBookies - All the bookies in the cluster available for write/read.

readOnlyBookies - All the bookies in the cluster available for readonly.

Returns:

the dead bookies during this cluster change.

newEnsemble

ArrayList<org.apache.bookkeeper.net.BookieSocketAddress> newEnsemble(int ensembleSize,
                                                                   int writeQuorumSize,
                                                                   Set<org.apache.bookkeeper.net.BookieSocketAddress> excludeBookies)
                                                                     throws BKException.BKNotEnoughBookiesException

Choose numBookies bookies for ensemble. If the count is more than the number of available nodes, BKException.BKNotEnoughBookiesException is thrown.

Parameters:

ensembleSize - Ensemble Size

writeQuorumSize - Write Quorum Size

excludeBookies - Bookies that should not be considered as targets.

Returns:

list of bookies chosen as targets.

Throws:

BKException.BKNotEnoughBookiesException - if not enough bookies available.

replaceBookie

org.apache.bookkeeper.net.BookieSocketAddress replaceBookie(org.apache.bookkeeper.net.BookieSocketAddress bookieToReplace,
                                                          Set<org.apache.bookkeeper.net.BookieSocketAddress> excludeBookies)
                                                            throws BKException.BKNotEnoughBookiesException

Choose a new bookie to replace bookieToReplace. If no bookie available in the cluster, BKException.BKNotEnoughBookiesException is thrown.

Parameters:

bookieToReplace - bookie to replace

excludeBookies - bookies that should not be considered as candidate.

Returns:

the bookie chosen as target.

Throws:

BKException.BKNotEnoughBookiesException