Package org.apache.hadoop.ha

Interface Summary

Interface	Description
ActiveStandbyElector.ActiveStandbyElectorCallback	Callback interface to interact with the ActiveStandbyElector object.
FenceMethod	A fencing method is a method by which one node can forcibly prevent another node from making continued progress.
HAServiceProtocol	Protocol interface that provides High Availability related primitives to monitor and fail-over the service.
ZKFCProtocol	Protocol exposed by the ZKFailoverController, allowing for graceful failover.

Class Summary

Class	Description
ActiveStandbyElector	This class implements a simple library to perform leader election on top of Apache Zookeeper.
FailoverController	The FailOverController is responsible for electing an active service on startup or when the current active is changing (eg due to failure), monitoring the health of a service, and performing a fail-over when a new active service is either manually selected by a user or elected.
HAAdmin	A command-line tool for making calls in the HAServiceProtocol.
HAAdmin.UsageInfo	UsageInfo class holds args and help details.
HAServiceProtocol.StateChangeRequestInfo	Information describing the source for a request to change state.
HAServiceProtocolHelper	Helper for making HAServiceProtocol RPC calls.
HAServiceStatus
HAServiceTarget	Represents a target of the client side HA administration commands.
HealthMonitor	This class is a daemon which runs in a loop, periodically heartbeating with an HA service.
NodeFencer	This class parses the configured list of fencing methods, and is responsible for trying each one in turn while logging informative output.
PowerShellFencer	Fencer method that uses PowerShell to remotely connect to a machine and kill the required process.
ShellCommandFencer	Fencing method that runs a shell command.
SshFenceByTcpPort	This fencing implementation sshes to the target node and uses fuser to kill the process listening on the service's TCP port.
ZKFailoverController
ZKFCRpcServer

Enum Summary

Enum	Description
HAServiceProtocol.HAServiceState	An HA service may be in active or standby state.
HAServiceProtocol.RequestSource
HealthMonitor.State

Exception Summary

Exception	Description
ActiveStandbyElector.ActiveNotFoundException	Exception thrown when there is no active leader
BadFencingConfigurationException	Indicates that the operator has specified an invalid configuration for fencing methods.
FailoverFailedException	Exception thrown to indicate service failover has failed.
HealthCheckFailedException	Exception thrown to indicate that health check of a service failed.
ServiceFailedException	Exception thrown to indicate that an operation performed to modify the state of a service or application failed.