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?

408


Explain the use of tasktracker in the hadoop cluster?

372


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

418


What do you know about sequencefileinputformat?

363


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

379


Why the name ‘hadoop’?

393


What do you know about nlineoutputformat?

391


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

382


How is hadoop different from other data processing tools?

402


What happens in a textinputformat?

386


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

381


Can we call vms as pseudos?

393


What do the master class and the output class do?

392


What does job conf class do?

381