Hadoop gen1 vs Hadoop gen2

Question

I am a bit confused about place of tasktracker in Hadoop-2.x.

Daemons in Hadoop-1.x are namenode, datanode, jobtracker, taskracker and secondaryna

Answer 1

Yes Jobtracker was split into resource manager and application master. Application master runs on one or all node managers instances based on the number of jobs submitted. So when job submitted, resource manager talks to one of free node managers to act as application master and that application master will be now job tracker and other node managers will be task trackers which they execute Yarn child. find details here: http://ercoppa.github.io/HadoopInternals/HadoopArchitectureOverview.html