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

Interface ActiveNamenodeResolver

All Known Implementing Classes:

MembershipNamenodeResolver

@Private
@Evolving
public interface ActiveNamenodeResolver

Locates the most active NN for a given nameservice ID or blockpool ID. This interface is used by the RouterRpcServer to:

• Determine the target NN for a given subcluster.
• List of all namespaces discovered/active in the federation.
• Update the currently active NN empirically.

The interface is also used by the NamenodeHeartbeatService to register a discovered NN.

Method Summary

Modifier and Type	Method	Description
java.util.Set<java.lang.String>	getDisabledNamespaces()	Get a list of all namespaces that are disabled.
java.util.List<? extends FederationNamenodeContext>	getNamenodesForBlockPoolId(java.lang.String blockPoolId)	Returns a prioritized list of the most recent cached registration entries for a single block pool ID.
java.util.List<? extends FederationNamenodeContext>	getNamenodesForNameserviceId(java.lang.String nameserviceId, boolean listObserversFirst)	Returns a prioritized list of the most recent cached registration entries for a single nameservice ID.
java.util.Set<FederationNamespaceInfo>	getNamespaces()	Get a list of all namespaces that are registered and active in the federation.
boolean	registerNamenode(NamenodeStatusReport report)	Register a namenode in the State Store.
void	rotateCache(java.lang.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(java.lang.String routerId)	Assign a unique identifier for the parent router service.
void	updateActiveNamenode(java.lang.String ns, java.net.InetSocketAddress successfulAddress)	Report a successful, active NN address for a nameservice or blockPool.
void	updateUnavailableNamenode(java.lang.String ns, java.net.InetSocketAddress failedAddress)	Report a failed, unavailable NN address for a nameservice or blockPool.

Method Detail

updateUnavailableNamenode

void updateUnavailableNamenode(java.lang.String ns,
                               java.net.InetSocketAddress failedAddress)
                        throws java.io.IOException

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

Parameters:

ns - Nameservice identifier.

failedAddress - The address the failed responded to the command.

Throws:

java.io.IOException - If the state store cannot be accessed.

updateActiveNamenode

void updateActiveNamenode(java.lang.String ns,
                          java.net.InetSocketAddress successfulAddress)
                   throws java.io.IOException

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

Parameters:

ns - Nameservice identifier.

successfulAddress - The address the successful responded to the command.

Throws:

java.io.IOException - If the state store cannot be accessed.

getNamenodesForNameserviceId

java.util.List<? extends FederationNamenodeContext> getNamenodesForNameserviceId(java.lang.String nameserviceId,
                                                                                 boolean listObserversFirst)
                                                                          throws java.io.IOException

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

Parameters:

nameserviceId - Nameservice identifier.

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

Returns:

Prioritized list of namenode contexts.

Throws:

java.io.IOException - If the state store cannot be accessed.

getNamenodesForBlockPoolId

java.util.List<? extends FederationNamenodeContext> getNamenodesForBlockPoolId(java.lang.String blockPoolId)
                                                                        throws java.io.IOException

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

Parameters:

blockPoolId - Block pool identifier for the nameservice.

Returns:

Prioritized list of namenode contexts.

Throws:

java.io.IOException - If the state store cannot be accessed.

registerNamenode

boolean registerNamenode(NamenodeStatusReport report)
                  throws java.io.IOException

Register a namenode in the State Store.

Parameters:

report - Namenode status report.

Returns:

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

Throws:

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

getNamespaces

java.util.Set<FederationNamespaceInfo> getNamespaces()
                                              throws java.io.IOException

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

Returns:

List of name spaces in the federation

Throws:

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

getDisabledNamespaces

java.util.Set<java.lang.String> getDisabledNamespaces()
                                               throws java.io.IOException

Get a list of all namespaces that are disabled.

Returns:

List of name spaces identifier in the federation

Throws:

java.io.IOException - If the disabled list is not available.

setRouterId

void setRouterId(java.lang.String routerId)

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

Parameters:

routerId - Unique string identifier for the router.

rotateCache

void rotateCache(java.lang.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.

Parameters:

nsId - name service id

namenode - namenode contexts

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