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Each time the bsp master receives a heartbeat message, it brings up-to-date groom server status - the bsp master makes use of groom servers' status in order to effectively assign tasks to idle groom servers - and returns a heartbeat response that contains assigned tasks and others actions that a groom server has to do. For now, we have a FIFO job scheduler and very simple task assignment algorithms.
GroomServer
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A [Groom Server|GroomServer] (shortly referred to as groom) is a process |
that manages life cycle of bsp tasks assigned by BSPMaster. Each groom contacts the BSPMaster, and reports task statuses by means of periodical piggybacks with BSPMaster. Each groom is designed to run with HDFS or other distributed storages. Basically, a groom server and a data node should be run on one physical node to get the best performance for data-locality. However, in a massive parallel environment, the benefit of data locality is lost when large amount of virtual processes must be multiplexed onto physical processes\[1\]. |
Zookeeper
A Zookeeper is used to manage the efficient barrier synchronization of the BSPPeers. Later, it will also be used for the area of a fault tolerance system.
Reference
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\[1\]. David B. Skillicorn, Jonathan M. D. Hill, and W. F. [McColl]. Questions and Answers about BSP. Scientific Programming, 6(3):249-274, Fall 1997. |