When can a reduce class also serve as a combiner without affecting the output of a MapReduce
program?

Your cluster’s HDFS block size in 64MB. You have directory containing 100 plain text files, each of

which is 100MB in size. The InputFormat for your job is TextInputFormat. Determine how many
Mappers will run?

You want to run Hadoop jobs on your development workstation for testing before you submit them
to your production cluster. Which mode of operation in Hadoop allows you to most closely simulate
a production cluster while using a single machine?

When is the earliest point at which the reduce method of a given Reducer can be called?

You are developing a combiner that takes as input Text keys, IntWritable values, and emits Text
keys, IntWritable values. Which interface should your class implement?

Assuming default settings, which best describes the order of data provided to a reducer’s reduce
method:

You wrote a map function that throws a runtime exception when it encounters a control character
in input data. The input supplied to your mapper contains twelve such characters totals, spread
across five file splits. The first four file splits each have two control characters and the last split has
four control characters.

Indentify the number of failed task attempts you can expect when you run the job with
mapred.max.map.attempts set to 4:

Which describes how a client reads a file from HDFS?

Indentify the utility that allows you to create and run MapReduce jobs with any executable or script
as the mapper and/or the reducer?

How are keys and values presented and passed to the reducers during a standard sort and shuffle
phase of MapReduce?