CCD-410: Cloudera Certified Developer for Apache Hadoop (CCDH) Exam | Practice Test / Quiz / MCQs

1. In the reducer, the MapReduce API provides you with an iterator over Writable values. What does calling the next () method return?

It returns a reference to a different Writable object time.It returns a reference to a Writable object from an object pool.It returns a reference to the same Writable object each time, but populated with different data.It returns a reference to a Writable object.The API leaves unspecified whether this is a reused object or a new object.

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

The default partitioner computers the hash of the key and divides that valule modulo the number of reducers. The result determines the reducer assigned to process the key-value pair.The default partitioner computers the hash of the key. Hash values between specific ranges are associated with different buckets, and each bucket is assigned to a specific reducer.The default partitioner implements a round-robin strategy, shuffling the key-value pairs to each reducer in turn. This ensures an event partition of the key space.The default partitioner assigns key-values pairs to reduces based on an internal random number generator.

4. You want to perform analysis on a large collection of images. You want to store this data in HDFS and process it with MapReduce but you also want to give your data analysts and data scientists the ability to process the data directly from HDFS with an interpreted high-level programming language like Python. Which format should you use to store this data in HDFS?

SequenceFilesAvroJSONHTML

6. MapReduce v2 (MRv2/YARN) is designed to address which two issues?

Resource pressure on the JobTracker.Single point of failure in the NameNode. Ability to run frameworks other than MapReduce, such as MPI.Reduce complexity of the MapReduce APIs.HDFS latency.

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

ResourceManagerNodeManagerApplicationMasterServiceApplicationMaster

8. You have just executed a MapReduce job. Where is intermediate data written to after being emitted from the Mapper s map method?

Into in-memory buffers on the TaskTracker node running the Mapper that spill over and are written into HDFS.Into in-memory buffers that spill over to the local file system (outside HDFS) of the TaskTracker node running the ReducerIntermediate data in streamed across the network from Mapper to the Reduce and is never written to disk.Into in-memory buffers that spill over to the local file system of the TaskTracker node running the Mapper.

9. You want to populate an associative array in order to perform a map-side join. You ?v decided to put this information in a text file, place that file into the DistributedCache and read it in your Mapper before any records are processed. Indentify which method in the Mapper you should use to implement code for reading the file and populating the associative array?

combineconfigureinitmap

10. What data does a Reducer reduce method process?

All data for a given key, regardless of which mapper(s) produced it.All data produced by a single mapper.All the data in a single input file.All data for a given value, regardless of which mapper(s) produced it.

11. You have user profile records in your OLPT database, that you want to join with web logs you have already ingested into the Hadoop file system. How will you obtain these user records?

Sqoop importPig LOAD commandHDFS commandHive LOAD DATA command

13. Determine which best describes when the reduce method is first called in a MapReduce job?

Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The reduce method is called as soon as the intermediate key-value pairs start to arrive.Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The reduce method is called only after all intermediate data has been copied and sorted.Reduce methods and map methods all start at the beginning of a job, in order to provide optimal performance for map-only or reduce-only jobs.Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The programmer can configure in the job what percentage of the intermediate data should arrive before the reduce method begins.

14. On a cluster running MapReduce v1 (MRv1), a TaskTracker heartbeats into the JobTracker on your cluster, and alerts the JobTracker it has an open map task slot. What determines how the JobTracker assigns each map task to a TaskTracker?

The location of the InsputSplit to be processed in relation to the location of the node.The amount of free disk space on the TaskTracker node.The amount of RAM installed on the TaskTracker node.The number and speed of CPU cores on the TaskTracker node.

15. You need to move a file titled weblogs into HDFS. When you try to copy the file, you can t. You know you have ample space on your DataNodes. Which action should you take to relieve this situation and store more files in HDFS?

Increase the block size on all current files in HDFS.Increase the block size on your remaining files.Increase the amount of memory for the NameNode.Decrease the block size on your remaining files.

16. Which describes how a client reads a file from HDFS?

The client queries all DataNodes in parallel. The DataNode that contains the requested data responds directly to the client. The client reads the data directly off the DataNode.The client contacts the NameNode for the block location(s).The NameNode then queries the DataNodes for block locations. The DataNodes respond to the NameNode, and the NameNode redirects the client to the DataNode that holds the requested data block(s).The client then reads the data directly off the DataNode.The client contacts the NameNode for the block location(s).The NameNode contacts the DataNode that holds the requested data block. Data is transferred from the DataNode to the NameNode, and then from the NameNode to the client.The client queries the NameNode for the block location(s).The NameNode returns the block location(s) to the client. The client reads the data directory off the DataNode(s).

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

Large-scale graph algorithms that require one-step link traversal.Relational operations on large amounts of structured and semi-structured data.Algorithms that require global, sharing states.Algorithms that require applying the same mathematical function to large numbers of individual binary records.

18. You have written a Mapper which invokes the following five calls to the OutputColletor.collect method: output.collect (new Text ( Apple ), new Text ( Red ) ) ; output.collect (new Text ( Banana ), new Text ( Yellow ) ) ; output.collect (new Text ( Apple ), new Text ( Yellow ) ) ; output.collect (new Text ( Cherry ), new Text ( Red ) ) ; output.collect (new Text ( Apple ), new Text ( Green ) ) ; How many times will the Reducer s reduce method be invoked?

3160

19. You have a directory named jobdata in HDFS that contains four files: _first.txt, second.txt, .third.txt and #data.txt. How many files will be processed by the FileInputFormat.setInputPaths () command when it's given a path object representing this directory?

None, the directory cannot be named jobdataFour, all files will be processedTwo, file names with a leading period or underscore are ignoredThree, the pound sign is an invalid character for HDFS file names

20. All keys used for intermediate output from mappers must:

Implement WritableComparable.Be a subclass of FileInputFormat.Override isSplitable. Implement a splittable compression algorithm.

21. 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.

NameNodeDataNodeTaskTrackerJobTracker

22. 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?

Place the data file in the DistributedCache and read the data into memory in the map method of the mapper.Serialize the data file, insert in it the JobConf object, and read the data into memory in the configure method of the mapper.Place the data file in the DistributedCache and read the data into memory in the configure method of the mapper.Place the data file in the DataCache and read the data into memory in the configure method of the mapper.

23. 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 C?

The file will be marked as corrupted if data node B fails during the creation of the file.Each data node locks the local file to prohibit concurrent readers and writers of the file.The file can be accessed if at least one of the data nodes storing the file is available.Each data node stores a copy of the file in the local file system with the same name as the HDFS file.

24. Indentify which best defines a SequenceFile?

A SequenceFile contains a binary encoding of an arbitrary number of heterogeneous Writable objectsA SequenceFile contains a binary encoding of an arbitrary number of WritableComparable objects, in sorted order.A SequenceFile contains a binary encoding of an arbitrary number of homogeneous Writable objectsA SequenceFile contains a binary encoding of an arbitrary number key-value pairs.Each key must be the same type.Each value must be the same type.

25. You use the hadoop fs put command to write a 300 MB file using and HDFS block size of 64 MB. Just after this command has finished writing 200 MB of this file, what would another user see when trying to access this life?

They would see Hadoop throw an ConcurrentFileAccessException when they try to access this file.They would see no content until the whole file written and closed.They would see the current of the file through the last completed block.They would see the current state of the file, up to the last bit written by the command.

25 Questions

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25 Questions

❤ If you liked Fatskills, consider supporting us by checking out The Life Manuals You Never Got.

About | Explore | User Guide | Topics | Subjects | Doubt Solver | Career Aptitude Test | Answers | Free Tools | OSHA Basics Quiz | What Should We Know? Privacy | Terms |

Without work one finishes nothing. - Ralph Waldo Emerson© 2026 Fatskills.com

All trademarks, logos and brand names are the property of their respective owners. All company, product and service names used in this website are for identification purposes only. Use of these names, trademarks and brands does not imply endorsement.

About | Explore | User Guide | Topics | Subjects | Doubt Solver | Career Aptitude Test | Answers | Free Tools | OSHA Basics Quiz | What Should We Know?
Privacy | Terms |

Without work one finishes nothing. - Ralph Waldo Emerson
© 2026 Fatskills.com