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

Class MembershipNamenodeResolver

java.lang.Object

org.apache.hadoop.hdfs.server.federation.resolver.MembershipNamenodeResolver

All Implemented Interfaces:

ActiveNamenodeResolver, StateStoreCache

public class MembershipNamenodeResolver
extends Object
implements ActiveNamenodeResolver, StateStoreCache

Implements a cached lookup of the most recently active namenode for a particular nameservice. Relies on the StateStoreService to discover available nameservices and namenodes.

Constructor Summary

Constructors

Constructor	Description
MembershipNamenodeResolver(org.apache.hadoop.conf.Configuration conf, StateStoreService store)

Method Summary

Modifier and Type	Method	Description
Set<String>	getDisabledNamespaces()	Get a list of all namespaces that are disabled.
List<? extends FederationNamenodeContext>	getNamenodesForBlockPoolId(String bpId)	Returns a prioritized list of the most recent cached registration entries for a single block pool ID.
List<? extends FederationNamenodeContext>	getNamenodesForNameserviceId(String nsId, boolean listObserversFirst)	Returns a prioritized list of the most recent cached registration entries for a single nameservice ID.
Set<FederationNamespaceInfo>	getNamespaces()	Get a list of all namespaces that are registered and active in the federation.
boolean	loadCache(boolean force)	Load the cache from the State Store.
boolean	registerNamenode(NamenodeStatusReport report)	Register a namenode in the State Store.
void	rotateCache(String nsId, FederationNamenodeContext namenode, boolean listObserversFirst)	Rotate cache, make the current namenode have the lowest priority, to ensure that the current namenode will not be accessed first next time.
void	setRouterId(String router)	Assign a unique identifier for the parent router service.
void	updateActiveNamenode(String nsId, InetSocketAddress address)	Report a successful, active NN address for a nameservice or blockPool.
void	updateUnavailableNamenode(String nsId, InetSocketAddress address)	Report a failed, unavailable NN address for a nameservice or blockPool.

Methods inherited from class java.lang.Object

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

Constructor Details

MembershipNamenodeResolver

public MembershipNamenodeResolver(org.apache.hadoop.conf.Configuration conf,
 StateStoreService store)
                           throws IOException

Throws:

IOException

Method Details

loadCache

public boolean loadCache(boolean force)

Description copied from interface: StateStoreCache

Load the cache from the State Store. Called by the cache update service when the data has been reloaded.

Specified by:

loadCache in interface StateStoreCache

Parameters:

force - If we force the load.

Returns:

If the cache was loaded successfully.

updateUnavailableNamenode

public void updateUnavailableNamenode(String nsId,
 InetSocketAddress address)
                               throws IOException

Description copied from interface: ActiveNamenodeResolver

Report a failed, unavailable NN address for a nameservice or blockPool.

Specified by:

updateUnavailableNamenode in interface ActiveNamenodeResolver

Parameters:

nsId - Nameservice identifier.

address - The address the failed responded to the command.

Throws:

IOException - If the state store cannot be accessed.

updateActiveNamenode

public void updateActiveNamenode(String nsId,
 InetSocketAddress address)
                          throws IOException

Description copied from interface: ActiveNamenodeResolver

Report a successful, active NN address for a nameservice or blockPool.

Specified by:

updateActiveNamenode in interface ActiveNamenodeResolver

Parameters:

nsId - Nameservice identifier.

address - The address the successful responded to the command.

Throws:

IOException - If the state store cannot be accessed.

getNamenodesForNameserviceId

public List<? extends FederationNamenodeContext> getNamenodesForNameserviceId(String nsId,
 boolean listObserversFirst)
                                                                       throws IOException

Description copied from interface: ActiveNamenodeResolver

Returns a prioritized list of the most recent cached registration entries for a single nameservice ID. Returns an empty list if none are found. In the case of not observerRead Returns entries in preference of :

• The most recent ACTIVE NN
• The most recent OBSERVER NN
• The most recent STANDBY NN
• The most recent UNAVAILABLE NN

In the case of observerRead Returns entries in preference of :

• The most recent OBSERVER NN
• The most recent ACTIVE NN
• The most recent STANDBY NN
• The most recent UNAVAILABLE NN

Specified by:

getNamenodesForNameserviceId in interface ActiveNamenodeResolver

Parameters:

nsId - Nameservice identifier.

listObserversFirst - Observer read case, observer NN will be ranked first

Returns:

Prioritized list of namenode contexts.

Throws:

IOException - If the state store cannot be accessed.

getNamenodesForBlockPoolId

public List<? extends FederationNamenodeContext> getNamenodesForBlockPoolId(String bpId)
                                                                     throws IOException

Description copied from interface: ActiveNamenodeResolver

Returns a prioritized list of the most recent cached registration entries for a single block pool ID. Returns an empty list if none are found. Returns entries in preference of:

• The most recent ACTIVE NN
• The most recent OBSERVER NN
• The most recent STANDBY NN
• The most recent UNAVAILABLE NN

Specified by:

getNamenodesForBlockPoolId in interface ActiveNamenodeResolver

Parameters:

bpId - Block pool identifier for the nameservice.

Returns:

Prioritized list of namenode contexts.

Throws:

IOException - If the state store cannot be accessed.

registerNamenode

public boolean registerNamenode(NamenodeStatusReport report)
                         throws IOException

Description copied from interface: ActiveNamenodeResolver

Register a namenode in the State Store.

Specified by:

registerNamenode in interface ActiveNamenodeResolver

Parameters:

report - Namenode status report.

Returns:

True if the node was registered and successfully committed to the data store.

Throws:

IOException - Throws exception if the namenode could not be registered.

getNamespaces

public Set<FederationNamespaceInfo> getNamespaces()
                                           throws IOException

Description copied from interface: ActiveNamenodeResolver

Get a list of all namespaces that are registered and active in the federation.

Specified by:

getNamespaces in interface ActiveNamenodeResolver

Returns:

List of name spaces in the federation

Throws:

IOException - Throws exception if the namespace list is not available.

getDisabledNamespaces

public Set<String> getDisabledNamespaces()
                                  throws IOException

Description copied from interface: ActiveNamenodeResolver

Get a list of all namespaces that are disabled.

Specified by:

getDisabledNamespaces in interface ActiveNamenodeResolver

Returns:

List of name spaces identifier in the federation

Throws:

IOException - If the disabled list is not available.

setRouterId

public void setRouterId(String router)

Description copied from interface: ActiveNamenodeResolver

Assign a unique identifier for the parent router service. Required to report the status to the namenode resolver.

Specified by:

setRouterId in interface ActiveNamenodeResolver

Parameters:

router - Unique string identifier for the router.

rotateCache

public void rotateCache(String nsId,
 FederationNamenodeContext namenode,
 boolean listObserversFirst)

Rotate cache, make the current namenode have the lowest priority, to ensure that the current namenode will not be accessed first next time.

Specified by:

rotateCache in interface ActiveNamenodeResolver

Parameters:

nsId - name service id.

namenode - namenode contexts.

listObserversFirst - Observer read case, observer NN will be ranked first.