Hortonworks Hortonworks Certifications HDPCD Questions & Answers

• Question 61:

  Which one of the following statements regarding the components of YARN is FALSE?

  A. A Container executes a specific task as assigned by the ApplicationMaster

  B. The ResourceManager is responsible for scheduling and allocating resources

  C. A client application submits a YARW job to the ResourceManager

  D. The ResourceManager monitors and restarts any failed Containers

  Correct Answer: D

• Question 62:

  Which Two of the following statements are true about hdfs? Choose 2 answers

  A. An HDFS file that is larger than dfs.block.size is split into blocks

  B. Blocks are replicated to multiple datanodes

  C. HDFS works best when storing a large number of relatively small files

  D. Block sizes for all files must be the same size

  Correct Answer: AB

• Question 63:

  Given the following Pig command:

  logevents = LOAD andapos;input/my.logandapos; AS (date:chararray, levehstring, code:int, message:string);

  Which one of the following statements is true?

  A. The logevents relation represents the data from the my.log file, using a comma as the parsing delimiter

  B. The logevents relation represents the data from the my.log file, using a tab as the parsing delimiter

  C. The first field of logevents must be a properly-formatted date string or table return an error

  D. The statement is not a valid Pig command

  Correct Answer: B

• Question 64:

  What data does a Reducer reduce method process?

  A. All the data in a single input file.

  B. All data produced by a single mapper.

  C. All data for a given key, regardless of which mapper(s) produced it.

  D. All data for a given value, regardless of which mapper(s) produced it.

  Correct Answer: C

  Explanation: Reducing lets you aggregate values together. A reducer function receives an iterator of input values from an input list. It then combines these values together, returning a single output value.

  All values with the same key are presented to a single reduce task.

  Reference: Yahoo! Hadoop Tutorial, Module 4: MapReduce

• Question 65:

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

  A. Oozie

  B. Sqoop

  C. Flume

  D. Hadoop Streaming

  E. mapred

  Correct Answer: D

  Explanation: Hadoop streaming is a utility that comes with the Hadoop distribution. The utility allows you to create and run Map/Reduce jobs with any executable or script as the mapper and/or the reducer.

  Reference: http://hadoop.apache.org/common/docs/r0.20.1/streaming.html (Hadoop Streaming, second sentence)

• Question 66:

  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?

  A. Combiner

  B. Mapper

  C. Reducer

  D. Reducer

  E. Combiner

  Correct Answer: D

• Question 67:

  Which one of the following statements is FALSE regarding the communication between DataNodes and a federation of NameNodes in Hadoop 2.2?

  A. Each DataNode receives commands from one designated master NameNode.

  B. DataNodes send periodic heartbeats to all the NameNodes.

  C. Each DataNode registers with all the NameNodes.

  D. DataNodes send periodic block reports to all the NameNodes.

  Correct Answer: A

• Question 68:

  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?

  A. Serialize the data file, insert in it the JobConf object, and read the data into memory in the configure method of the mapper.

  B. Place the data file in the DistributedCache and read the data into memory in the map method of the mapper.

  C. Place the data file in the DataCache and read the data into memory in the configure method of the mapper.

  D. Place the data file in the DistributedCache and read the data into memory in the configure method of the mapper.

  Correct Answer: C

• Question 69:

  Workflows expressed in Oozie can contain:

  A. Sequences of MapReduce and Pig. These sequences can be combined with other actions including forks, decision points, and path joins.

  B. Sequences of MapReduce job only; on Pig on Hive tasks or jobs. These MapReduce sequences can be combined with forks and path joins.

  C. Sequences of MapReduce and Pig jobs. These are limited to linear sequences of actions with exception handlers but no forks.

  D. Iterntive repetition of MapReduce jobs until a desired answer or state is reached.

  Correct Answer: A

  Explanation: Oozie workflow is a collection of actions (i.e. Hadoop Map/Reduce jobs, Pig jobs) arranged in a control dependency DAG (Direct Acyclic Graph), specifying a sequence of actions execution. This graph is specified in hPDL (a XML Process Definition Language).

  hPDL is a fairly compact language, using a limited amount of flow control and action nodes. Control nodes define the flow of execution and include beginning and end of a workflow (start, end and fail nodes) and mechanisms to control the workflow execution path ( decision, fork and join nodes).

  Workflow definitions Currently running workflow instances, including instance states and variables

  Reference: Introduction to Oozie

  Note: Oozie is a Java Web-Application that runs in a Java servlet-container - Tomcat and uses a database to store:

• Question 70:

  Given the following Hive command:

  

  Which one of the following statements is true?

  A. The files in the mydata folder are copied to a subfolder of /apps/hlve/warehouse

  B. The files in the mydata folder are moved to a subfolder of /apps/hive/wa re house

  C. The files in the mydata folder are copied into Hive's underlying relational database

  D. The files in the mydata folder do not move from their current location In HDFS

  Correct Answer: D