Package alluxio.worker

Worker process and utils for working with the worker remotely.

See: Description

Interface Summary

Interface	Description
DataServer	Defines how to interact with a server running the data protocol.
SessionCleanable	Interface for classes which track sessions and provide a method to clean any expired sessions.
Worker	Interface of an Alluxio worker.
WorkerFactory	Interface for factory of Worker.
WorkerProcess	A worker in the Alluxio system.

Class Summary

Class	Description
AbstractWorker	This is the base class for all workers, and contains common functionality.
AlluxioWorker	Entry point for the Alluxio worker.
AlluxioWorkerMonitor	Alluxio worker monitor for inquiring AlluxioWorker service availability.
AlluxioWorkerProcess	This class encapsulates the different worker services that are configured to run.
AlluxioWorkerRestServiceHandler	This class is a REST handler for requesting general worker information.
DataServer.Factory	Factory for DataServer.
SessionCleaner	SessionCleaner periodically checks if any session have become zombies, removes the zombie session and associated data when necessary.
WorkerHealthCheckClient	WorkerHealthCheckClient check if worker is serving RPC.
WorkerProcess.Factory	Factory for creating WorkerProcess.
WorkerRegistry	A worker registry.

Package alluxio.worker Description

Worker process and utils for working with the worker remotely. Main entry point for the worker is AlluxioWorker.main(java.lang.String[]) which gets started by the alluxio start scripts. The WorkerProcess spins up the different RPC services (thrift, data) which are mostly wrappers around BlockWorker.

Services

DataServer

This service is the main interaction between users and worker for reading and writing blocks. The DataServer interface defines how to start/stop, and get port details; to start, object init is used. The implementation of this interface is in NettyDataServer. It creates an DataServer instance based on Netty which is an asynchronous event-driven network application framework. Data server handles the following types of block requests:

• Read blocks in worker storage from network
• Read blocks in worker storage from local file system: short-circuit read for local client
• Read blocks in UFS
• Write blocks in worker storage from network
• Write blocks in worker storage from local file system: short-circuit write for local client
• Write blocks in UFS

The current protocol is described in Protocol. All the requests are generated by Protobuf to keep the protocol extensible but also backward-compatible.

Thrift

The thrift service on worker side has been deprecated since v1.5. It used to serve metadata operations (with a few operations that effect the worker's cached memory) such as lock unlock, access, request space for blocks. It has been completely replaced by the DataServer service.