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

2. 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?

3. Identify the MapReduce v2 (MRv2 / YARN) daemon responsible for launching application containers and monitoring application resource usage?

4. Which best describes what the map method accepts and emits?

5. For each input key-value pair, mappers can emit:

6. You've written a MapReduce job that will process 500 million input records and generated 500 million key- value pairs. The data is not uniformly distributed. Your MapReduce job will create a significant amount of intermediate data that it needs to transfer between mappers and reduces which is a potential bottleneck. A custom implementation of which interface is most likely to reduce the amount of intermediate data transferred across the network?

7. In a MapReduce job, you want each of your input files processed by a single map task. How do you configure a MapReduce job so that a single map task processes each input file regardless of how many blocks the input file occupies?

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

9. You write MapReduce job to process 100 files in HDFS. Your MapReduce algorithm uses TextInputFormat: the mapper applies a regular expression over input values and emits key-values pairs with the key consisting of the matching text, and the value containing the filename and byte offset. Determine the difference between setting the number of reduces to one and settings the number of reducers to zero.

10. A combiner reduces:

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

12. Which process describes the lifecycle of a Mapper?

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

14. A client application creates an HDFS file named foo.txt with a replication factor of 3. Identify which best describes the file access rules in HDFS if the file has a single block that is stored on data nodes A, B and

15. Indentify which best defines a SequenceFile?

16. 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?

17. Your client application submits a MapReduce job to your Hadoop cluster. Identify the Hadoop daemon on which the Hadoop framework will look for an available slot schedule a MapReduce operation.

18. In a large MapReduce job with m mappers and n reducers, how many distinct copy operations will there be in the sort/shuffle phase?

19. To process input key-value pairs, your mapper needs to lead a 512 MB data file in memory. What is the best way to accomplish this?

20. A combiner reduces:

21. Given a directory of files with the following structure: line number, tab character, string: Example: 1abialkjfjkaoasdfjksdlkjhqweroij 2kadfjhuwqounahagtnbvaswslmnbfgy 3kjfteiomndscxeqalkzhtopedkfsikj You want to send each line as one record to your Mapper. Which InputFormat should you use to complete the line: conf.setInputFormat (____.class) ; ?

22. Analyze each scenario below and indentify which best describes the behavior of the default partitioner?

23. What types of algorithms are difficult to express in MapReduce v1 (MRv1)?

24. To process input key-value pairs, your mapper needs to lead a 512 MB data file in memory. What is the best way to accomplish this?

25. What data does a Reducer reduce method process?