Apache Hama is a distributed computing framework based on

bulk synchronous parallel The bulk synchronous parallel (BSP) abstract computer is a bridging model for designing parallel algorithms. It is similar to the parallel random access machine (PRAM) model, but unlike PRAM, BSP does not take communication and synchronization fo ...

computing techniques for massive scientific computations e.g., matrix, graph and network algorithms. It was a Top Level Project under the Apache Software Foundation. Retired in April 2020, project resources are made available as part of the

Apache Attic Apache Attic is a project of Apache Software Foundation to provide processes to make it clear when an Apache project has reached its end-of-life. The Attic project was created in November 2008. Also the retired projects can be retained. Projects m ...

. It was created by Edward J. Yoon, who named it (short for "Hadoop Matrix") and was inspired by

Google Google LLC () is an American Multinational corporation, multinational technology company focusing on Search Engine, search engine technology, online advertising, cloud computing, software, computer software, quantum computing, e-commerce, ar ...

's Pregel large-scale graph computing framework described in 2010. Hama also means

hippopotamus The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two exta ...

in Korean language (하마), following the trend of naming Apache projects after animals and zoology (such as Apache Pig).

Architecture

Hama consists of three major components: BSPMaster, GroomServers and Zookeeper.Apache Hama Architecture
/ref>

BSPMaster

BSPMaster is responsible for: * Maintaining groom server status * Controlling super steps in a cluster * Maintaining job progress information * Scheduling jobs and assigning tasks to groom servers * Disseminating execution class across groom servers * Controlling fault * Providing users with the cluster control interface. A BSP Master and multiple grooms are started by the script. Then, the bsp master starts up with a RPC server for groom servers. Groom servers starts up with a BSPPeer instance and a RPC proxy to contact the bsp master. After started, each groom periodically sends a heartbeat message that encloses its groom server status, including maximum task capacity, unused memory, and so on. 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

A groom server (shortly referred to as groom) is a process that performs BSP tasks assigned by BSPMaster. Each groom contacts the BSPMaster, and it takes assigned tasks and reports its status 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.

Zookeeper

A Zookeeper is used to manage the efficient barrier synchronisation of the BSPPeers.

References

External links

Apache Hama WebsiteApache Hama blog
{{Apache Software Foundation

Hama Hama ( ar, حَمَاة ', ; syr, ܚܡܬ, ħ(ə)mɑθ, lit=fortress; Biblical Hebrew: ''Ḥamāṯ'') is a city on the banks of the Orontes River in west-central Syria. It is located north of Damascus and north of Homs. It is the provinci ...