Map reduce jobs are failing on a cluster that was just restarted. They worked before restart. What could be wrong?

602

When should you use a reducer?

630

What do you understand by compute and storage nodes?

681

What is a scarce system resource?

653

In Map Reduce why map write output to Local Disk instead of HDFS?

903

How many numbers of reducers run in Map-Reduce Job?

610

What is the default value of map and reduce max attempts?

932

Detail description of the Reducer phases?

852

What happen if the number of the reducer is 0 in MapReduce?

652

What combiners is and when you should use a combiner in a MapReduce Job?

624

Explain what combiners are and when you should use a combiner in a mapreduce job?

615

What is a RecordReader in Hadoop MapReduce?

676

How to submit extra files(jars, static files) for Hadoop MapReduce job during runtime?

635

Define MapReduce?

689

In MapReduce how to change the name of the output file from part-r-00000?

627