1.What are “slaves” and “masters” in Hadoop?
Ans:We Have 5 deamons In Hadoop
HDFS Daeamons Are 1.Name Node
2.Secondary Name Node
3.Data Node
Map Reduce Deamons Are 1.Job Tracker
2.Task Tracker
The Masters Deamons In Hadoop Are Name Node,Secondary Name Node and Job Tracker
The Slaves Deamons In Hadoop Are Data Node and Task Tracker.

2.How many datanodes can run on a single Hadoop cluster?
Ans: In Hadoop Single Node Cluster ‘n’ Number Of Data Nodes Are Running.

3.What is job tracker in Hadoop?
Ans:The Job Tracker Is A Master Node In Hadoop And It Assigns Job To The Respective Task Tracker.

4.What is “jps”?
Ans:Jps Means Java Processor.

5.What is the purpose of RecordReader in Hadoop?
Ans: It Can Read One Line At A Time And It Breaks The Key Value Pair And It Just Writes The Output.