Un-Answered Questions { Apache Hadoop }

What is the jobtracker and what it performs in a hadoop cluster?

371


How many instances of tasktracker run on a hadoop cluster?

414


Explain the use of tasktracker in the hadoop cluster?

376


How does a namenode handle the failure of the data nodes?

420


What do you know about sequencefileinputformat?

369


Why we cannot do aggregation (addition) in a mapper? Why we require reducer for that?

383


Why the name ‘hadoop’?

397


What do you know about nlineoutputformat?

393


How can we change the split size if our commodity hardware has less storage space?

384


How is hadoop different from other data processing tools?

407


What happens in a textinputformat?

392


Can you explain how do ‘map’ and ‘reduce’ work?

381


Can we call vms as pseudos?

399


What do the master class and the output class do?

400


What does job conf class do?

383