diff --git hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/YARN.md hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/YARN.md index f79272c..c41c9bf 100644 --- hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/YARN.md +++ hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/YARN.md @@ -12,12 +12,10 @@ limitations under the License. See accompanying LICENSE file. --> -Apache Hadoop NextGen MapReduce (YARN) +Apache Hadoop Yarn ================== -MapReduce has undergone a complete overhaul in hadoop-0.23 and we now have, what we call, MapReduce 2.0 (MRv2) or YARN. - -The fundamental idea of MRv2 is to split up the two major functionalities of the JobTracker, resource management and job scheduling/monitoring, into separate daemons. The idea is to have a global ResourceManager (*RM*) and per-application ApplicationMaster (*AM*). An application is either a single job in the classical sense of Map-Reduce jobs or a DAG of jobs. +The fundamental idea of YARN is to split up the two major functionalities of the JobTracker, resource management and job scheduling/monitoring, into separate daemons. The idea is to have a global ResourceManager (*RM*) and per-application ApplicationMaster (*AM*). An application is either a single job in the classical sense of Map-Reduce jobs or a DAG of jobs. The ResourceManager and per-node slave, the NodeManager (*NM*), form the data-computation framework. The ResourceManager is the ultimate authority that arbitrates resources among all the applications in the system. @@ -39,4 +37,4 @@ The NodeManager is the per-machine framework agent who is responsible for contai The per-application ApplicationMaster has the responsibility of negotiating appropriate resource containers from the Scheduler, tracking their status and monitoring for progress. -MRV2 maintains **API compatibility** with previous stable release (hadoop-1.x). This means that all Map-Reduce jobs should still run unchanged on top of MRv2 with just a recompile. +YARN maintains **API compatibility** with previous stable release (hadoop-1.x). This means that all Map-Reduce jobs should still run unchanged on top of YARN with just a recompile.