Package org.apache.hadoop.hdfs.server.federation.store

Class MembershipStore

java.lang.Object

org.apache.hadoop.hdfs.server.federation.store.RecordStore<R>

org.apache.hadoop.hdfs.server.federation.store.CachedRecordStore<MembershipState>

org.apache.hadoop.hdfs.server.federation.store.MembershipStore

All Implemented Interfaces:

StateStoreCache

Direct Known Subclasses:

MembershipStoreImpl

@Private
@Evolving
public abstract class MembershipStore
extends CachedRecordStore<MembershipState>

Management API for NameNode registrations stored in MembershipState records. The RouterHeartbeatService periodically polls each NN to update the NameNode metadata(addresses, operational) and HA state(active, standby). Each NameNode may be polled by multiple Router instances.

Once fetched from the StateStoreDriver, NameNode registrations are cached until the next query. The fetched registration data is aggregated using a quorum to determine the best/most accurate state for each NameNode. The cache is periodically updated by the StateStoreCacheUpdateService.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MembershipStore(StateStoreDriver driver)

Method Summary

Modifier and Type	Method	Description
abstract GetNamenodeRegistrationsResponse	getExpiredNamenodeRegistrations(GetNamenodeRegistrationsRequest request)	Get the expired registrations from the registration cache.
abstract GetNamenodeRegistrationsResponse	getNamenodeRegistrations(GetNamenodeRegistrationsRequest request)	Queries for a single cached registration entry matching the given parameters.
abstract GetNamespaceInfoResponse	getNamespaceInfo(GetNamespaceInfoRequest request)	Retrieves a list of registered nameservices and their associated info.
abstract NamenodeHeartbeatResponse	namenodeHeartbeat(NamenodeHeartbeatRequest request)	Inserts or updates a namenode membership entry into the table.
abstract UpdateNamenodeRegistrationResponse	updateNamenodeRegistration(UpdateNamenodeRegistrationRequest request)	Overrides a cached namenode state with an updated state.

Methods inherited from class org.apache.hadoop.hdfs.server.federation.store.CachedRecordStore

getCachedRecords, getCachedRecordsAndTimeStamp, loadCache, overrideExpiredRecord, overrideExpiredRecords

Methods inherited from class org.apache.hadoop.hdfs.server.federation.store.RecordStore

getDriver, getRecordClass, newInstance

Methods inherited from class java.lang.Object

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

Constructor Detail

MembershipStore

protected MembershipStore(StateStoreDriver driver)

Method Detail

namenodeHeartbeat

public abstract NamenodeHeartbeatResponse namenodeHeartbeat(NamenodeHeartbeatRequest request)
                                                     throws java.io.IOException

Inserts or updates a namenode membership entry into the table.

Parameters:

request - Fully populated NamenodeHeartbeatRequest request.

Returns:

True if successful, false otherwise.

Throws:

StateStoreUnavailableException - Throws exception if the data store is not initialized.

java.io.IOException - if the data store could not be queried or the query is invalid.

getNamenodeRegistrations

public abstract GetNamenodeRegistrationsResponse getNamenodeRegistrations(GetNamenodeRegistrationsRequest request)
                                                                   throws java.io.IOException

Queries for a single cached registration entry matching the given parameters. Possible keys are the names of data structure elements Possible values are matching SQL "LIKE" targets.

Parameters:

request - Fully populated GetNamenodeRegistrationsRequest request.

Returns:

Single matching FederationMembershipStateEntry or null if not found or more than one entry matches.

Throws:

StateStoreUnavailableException - Throws exception if the data store is not initialized.

java.io.IOException - if the data store could not be queried or the query is invalid.

getExpiredNamenodeRegistrations

public abstract GetNamenodeRegistrationsResponse getExpiredNamenodeRegistrations(GetNamenodeRegistrationsRequest request)
                                                                          throws java.io.IOException

Get the expired registrations from the registration cache.

Parameters:

request - Request to get the expired registrations.

Returns:

Expired registrations or zero-length list if none are found.

Throws:

StateStoreUnavailableException - Throws exception if the data store is not initialized.

java.io.IOException - if the data store could not be queried or the query is invalid.

getNamespaceInfo

public abstract GetNamespaceInfoResponse getNamespaceInfo(GetNamespaceInfoRequest request)
                                                   throws java.io.IOException

Retrieves a list of registered nameservices and their associated info.

Parameters:

request - Request to get the name spaces.

Returns:

Collection of information for each registered nameservice.

Throws:

java.io.IOException - if the data store could not be queried or the query is invalid.

updateNamenodeRegistration

public abstract UpdateNamenodeRegistrationResponse updateNamenodeRegistration(UpdateNamenodeRegistrationRequest request)
                                                                       throws java.io.IOException

Overrides a cached namenode state with an updated state.

Parameters:

request - Fully populated OverrideNamenodeRegistrationRequest request.

Returns:

OverrideNamenodeRegistrationResponse

Throws:

StateStoreUnavailableException - if the data store is not initialized.

java.io.IOException - if the data store could not be queried or the query is invalid.