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

Class StateStoreService

java.lang.Object

org.apache.hadoop.service.AbstractService

org.apache.hadoop.service.CompositeService

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

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, org.apache.hadoop.service.Service

@Private
@Evolving
public class StateStoreService
extends org.apache.hadoop.service.CompositeService

A service to initialize a StateStoreDriver and maintain the connection to the data store. There are multiple state store driver connections supported:

• File StateStoreFileImpl
• FileSystem StateStoreFileSystemImpl
• MySQL StateStoreMySQLImpl
• ZooKeeper StateStoreZooKeeperImpl

The service also supports the dynamic registration of record stores like:

• MembershipStore: state of the Namenodes in the federation.
• MountTableStore: Mount table between to subclusters. See ViewFs.
• RouterStore: Router state in the federation.
• DisabledNameserviceStore: Disabled name services.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.service.CompositeService

org.apache.hadoop.service.CompositeService.CompositeServiceShutdownHook

Nested classes/interfaces inherited from interface org.apache.hadoop.service.Service

org.apache.hadoop.service.Service.STATE

Field Summary

Fields inherited from class org.apache.hadoop.service.CompositeService

STOP_ONLY_STARTED_SERVICES

Constructor Summary

Constructors

Constructor	Description
StateStoreService()

Method Summary

Modifier and Type	Method	Description
void	closeDriver()	Manually shuts down the driver.
long	getCacheUpdateTime()	The last time the state store cache was fully updated.
StateStoreDriver	getDriver()	Get the state store driver.
java.lang.String	getIdentifier()	Fetch a unique identifier for this state store instance.
StateStoreMetrics	getMetrics()	Get the metrics for the State Store.
<T extends RecordStore<? extends BaseRecord>> java.util.List<T>	getRecordStores()	Get the list of all RecordStores.
<T extends RecordStore<?>> T	getRegisteredRecordStore(java.lang.Class<T> recordStoreClass)	Get the record store in this State Store for a given interface.
java.util.Collection<java.lang.Class<? extends BaseRecord>>	getSupportedRecords()	List of records supported by this State Store.
boolean	isDriverReady()	Check if the driver is ready to be used.
boolean	loadCache(java.lang.Class<?> clazz)	Update the cache for a specific record store.
boolean	loadCache(java.lang.Class<?> clazz, boolean force)	Update the cache for a specific record store.
void	loadDriver()	Load the State Store driver.
void	refreshCaches()	Refresh the cache with information from the State Store.
void	refreshCaches(boolean force)	Refresh the cache with information from the State Store.
void	registerCacheExternal(StateStoreCache client)	Register a cached record store for automatic periodic cache updates.
protected void	serviceInit(org.apache.hadoop.conf.Configuration config)	Initialize the State Store and the connection to the back-end.
protected void	serviceStart()
protected void	serviceStop()
void	setIdentifier(java.lang.String id)	Set a unique synchronization identifier for this store.
void	stopCacheUpdateService()	Stops the cache update service.

Methods inherited from class org.apache.hadoop.service.CompositeService

addIfService, addService, getServices, removeService

Methods inherited from class org.apache.hadoop.service.AbstractService

close, getBlockers, getConfig, getFailureCause, getFailureState, getLifecycleHistory, getName, getServiceState, getStartTime, init, isInState, noteFailure, putBlocker, registerGlobalListener, registerServiceListener, removeBlocker, setConfig, start, stop, toString, unregisterGlobalListener, unregisterServiceListener, waitForServiceToStop

Methods inherited from class java.lang.Object

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

Constructor Detail

StateStoreService

public StateStoreService()

Method Detail

serviceInit

protected void serviceInit(org.apache.hadoop.conf.Configuration config)
                    throws java.lang.Exception

Initialize the State Store and the connection to the back-end.

Overrides:

serviceInit in class org.apache.hadoop.service.CompositeService

Parameters:

config - Configuration for the State Store.

Throws:

java.lang.Exception - Cannot create driver for the State Store.

serviceStart

protected void serviceStart()
                     throws java.lang.Exception

Overrides:

serviceStart in class org.apache.hadoop.service.CompositeService

Throws:

java.lang.Exception

serviceStop

protected void serviceStop()
                    throws java.lang.Exception

Overrides:

serviceStop in class org.apache.hadoop.service.CompositeService

Throws:

java.lang.Exception

getRegisteredRecordStore

public <T extends RecordStore<?>> T getRegisteredRecordStore(java.lang.Class<T> recordStoreClass)

Get the record store in this State Store for a given interface.

Type Parameters:

T - The type of the record store.

Parameters:

recordStoreClass - Class of the record store.

Returns:

Registered record store or null if not found.

getRecordStores

public <T extends RecordStore<? extends BaseRecord>> java.util.List<T> getRecordStores()

Get the list of all RecordStores.

Type Parameters:

T - The type of the record stores that are returned.

Returns:

a list of each RecordStore.

getSupportedRecords

public java.util.Collection<java.lang.Class<? extends BaseRecord>> getSupportedRecords()

List of records supported by this State Store.

Returns:

List of supported record classes.

loadDriver

public void loadDriver()

Load the State Store driver. If successful, refresh cached data tables.

isDriverReady

public boolean isDriverReady()

Check if the driver is ready to be used.

Returns:

If the driver is ready.

closeDriver

@VisibleForTesting
public void closeDriver()
                 throws java.lang.Exception

Manually shuts down the driver.

Throws:

java.lang.Exception - If the driver cannot be closed.

getDriver

public StateStoreDriver getDriver()

Get the state store driver.

Returns:

State store driver.

getIdentifier

public java.lang.String getIdentifier()

Fetch a unique identifier for this state store instance. Typically, it is the address of the router.

Returns:

Unique identifier for this store.

setIdentifier

public void setIdentifier(java.lang.String id)

Set a unique synchronization identifier for this store.

Parameters:

id - Unique identifier, typically the router's RPC address.

getCacheUpdateTime

public long getCacheUpdateTime()

The last time the state store cache was fully updated.

Returns:

Timestamp.

stopCacheUpdateService

@VisibleForTesting
public void stopCacheUpdateService()

Stops the cache update service.

registerCacheExternal

public void registerCacheExternal(StateStoreCache client)

Register a cached record store for automatic periodic cache updates.

Parameters:

client - Client to the state store.

refreshCaches

public void refreshCaches()

Refresh the cache with information from the State Store. Called periodically by the CacheUpdateService to maintain data caches and versions.

refreshCaches

public void refreshCaches(boolean force)

Refresh the cache with information from the State Store. Called periodically by the CacheUpdateService to maintain data caches and versions.

Parameters:

force - If we force the refresh.

loadCache

public boolean loadCache(java.lang.Class<?> clazz)
                  throws java.io.IOException

Update the cache for a specific record store.

Parameters:

clazz - Class of the record store.

Returns:

If the cached was loaded.

Throws:

java.io.IOException - if the cache update failed.

loadCache

public boolean loadCache(java.lang.Class<?> clazz,
                         boolean force)
                  throws java.io.IOException

Update the cache for a specific record store.

Parameters:

clazz - Class of the record store.

force - Force the update ignoring cached periods.

Returns:

If the cached was loaded.

Throws:

java.io.IOException - if the cache update failed.

getMetrics

public StateStoreMetrics getMetrics()

Get the metrics for the State Store.

Returns:

State Store metrics.