@Private @Evolving

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

The router package includes the core services for a HDFS federation router. The Router acts as a transparent proxy in front of a cluster of multiple NameNodes and nameservices. The RouterRpcServer exposes the NameNode clientProtocol and is the primary contact point for DFS clients in a federated cluster.

Interface Summary

Interface	Description
NameserviceManager	Interface for enable/disable name service.
RouterRpcMonitor	Metrics and monitoring interface for the router RPC server.
RouterStateManager	Interface of managing the Router state.

Class Summary

Class	Description
ConnectionContext	Context to track a connection in a ConnectionPool.
ConnectionManager	Implements a pool of connections for the Router to be able to open many connections to many Namenodes.
ConnectionPool	Maintains a pool of connections for each User (including tokens) + NN.
ConnectionPoolId	Identifier for a connection for a user to a namenode.
DFSRouter	Tool to start the Router for Router-based federation.
ErasureCoding	Module that implements all the RPC calls in ClientProtocol related to Erasure Coding in the RouterRpcServer.
FederationConnectionId
FederationUtil	Utilities for managing HDFS federation.
IsRouterActiveServlet	Detect if the Router is active and ready to serve requests.
MountTableRefresherService	This service is invoked from MountTableStore when there is change in mount table entries and it updates mount table entry cache on local router as well as on all remote routers.
MountTableRefresherThread	Base class for updating mount table cache on all the router.
NamenodeHeartbeatService	The Router periodically checks the state of a Namenode (usually on the same server) and reports their high availability (HA) state and load/space status to the StateStoreService .
PeriodicService	Service to periodically execute a runnable.
PoolAlignmentContext	An alignment context shared by all connections in a ConnectionPool.
Quota	Module that implements the quota relevant RPC calls ClientProtocol.setQuota(String, long, long, StorageType) and ClientProtocol.getQuotaUsage(String) in the RouterRpcServer.
RBFConfigKeys	Config fields for router-based hdfs federation.
RemoteLocationContext	Base class for objects that are unique to a namespace.
RemoteMethod	Determines the remote client protocol method and the parameter list for a specific location.
RemoteParam	A dynamically assignable parameter that is location-specific.
RemoteResult<T extends RemoteLocationContext,R>	Result from a remote location.
Router	Router that provides a unified view of multiple federated HDFS clusters.
RouterAdminServer	This class is responsible for handling all the Admin calls to the HDFS router.
RouterCacheAdmin	Module that implements all the RPC calls in ClientProtocol related to Cache Admin in the RouterRpcServer.
RouterClient	Client to connect to the Router via the admin protocol.
RouterClientMetrics	This class is for maintaining the various Router Client activity statistics and publishing them through the metrics interfaces.
RouterClientProtocol	Module that implements all the RPC calls in ClientProtocol in the RouterRpcServer.
RouterFederationRename	Rename across router federation namespaces based on federation balance.
RouterFsck	Wrapper for the Router to offer the Namenode FSCK.
RouterFsckServlet	This class is used in Namesystem's web server to do fsck on namenode.
RouterHeartbeatService	Service to periodically update the Router current state in the State Store.
RouterHttpServer	Web interface for the Router.
RouterMetrics	This class is for maintaining the various Router activity statistics and publishing them through the metrics interfaces.
RouterMetricsService	Service to manage the metrics of the Router.
RouterNamenodeProtocol	Module that implements all the RPC calls in NamenodeProtocol in the RouterRpcServer.
RouterNetworkTopologyServlet	A servlet to print out the network topology from router.
RouterPermissionChecker	Class that helps in checking permissions in Router-based federation.
RouterQuotaManager	Router quota manager in Router.
RouterQuotaUpdateService	Service to periodically update the RouterQuotaUsage cached information in the Router.
RouterQuotaUsage	The subclass of QuotaUsage used in Router-based federation.
RouterQuotaUsage.Builder	Build the instance based on the builder.
RouterRpcClient	A client proxy for Router to NN communication using the NN ClientProtocol.
RouterRpcServer	This class is responsible for handling all of the RPC calls to the It is created, started, and stopped by Router.
RouterSafemodeService	Service to periodically check if the StateStoreService cached information in the Router is up to date.
RouterSnapshot	Module that implements all the RPC calls related to snapshots in ClientProtocol in the RouterRpcServer.
RouterStoragePolicy	Module that implements all the RPC calls in ClientProtocol related to Storage Policy in the RouterRpcServer.
RouterUserProtocol	Module that implements all the RPC calls in RefreshUserMappingsProtocol GetUserMappingsProtocol in the RouterRpcServer.
RouterWebHdfsMethods	WebHDFS Router implementation.

Enum Summary

Enum	Description
RouterFederationRename.RouterRenameOption
RouterServiceState	States of the Router.

Exception Summary

Exception	Description
ConnectionNullException	Exception when can not get a non-null connection.
NoLocationException	This exception is thrown when can not get any mount point for the input path.
NoNamenodesAvailableException	Exception when no namenodes are available.
SubClusterTimeoutException	Exception when timing out waiting for the reply of a subcluster.