Which describes how a client reads a file from HDFS?

A. 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).

B. 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.

C. 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.

D. 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.

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

You've written a MapReduce job that will process 500 million input records and generated 500 million keyvalue 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?

A. Partitioner

B. OutputFormat

C. WritableComparable

D. Writable

E. InputFormat

F. Combiner

You want to understand more about how users browse your public website, such as which pages they visit

prior to placing an order. You have a farm of 200 web servers hosting your website.

How will you gather this data for your analysis?

A. Ingest the server web logs into HDFS using Flume.

B. Write a MapReduce job, with the web servers for mappers, and the Hadoop cluster nodes for reduces.

C. Import all users' clicks from your OLTP databases into Hadoop, using Sqoop.

D. Channel these clickstreams inot Hadoop using Hadoop Streaming.

E. Sample the weblogs from the web servers, copying them into Hadoop using curl.

You need to run the same job many times with minor variations. Rather than hardcoding all job configuration options in your drive code, you've decided to have your Driver subclass org.apache.hadoop.conf.Configured and implement the org.apache.hadoop.util.Tool interface. Indentify which invocation correctly passes.mapred.job.name with a value of Example to Hadoop?

A. hadoop "mapred.job.name=Example" MyDriver input output

B. hadoop MyDriver mapred.job.name=Example input output

C. hadoop MyDrive D mapred.job.name=Example input output

D. hadoop setproperty mapred.job.name=Example MyDriver input output

E. hadoop setproperty ("mapred.job.name=Example") MyDriver input output

For each intermediate key, each reducer task can emit:

A. As many final key-value pairs as desired. There are no restrictions on the types of those key- value pairs (i.e., they can be heterogeneous).

B. As many final key-value pairs as desired, but they must have the same type as the intermediate key-value pairs.

C. As many final key-value pairs as desired, as long as all the keys have the same type and all the values have the same type.

D. One final key-value pair per value associated with the key; no restrictions on the type.

E. One final key-value pair per key; no restrictions on the type.

Which project gives you a distributed, Scalable, data store that allows you random, realtime read/write access to hundreds of terabytes of data?

A. HBase

B. Hue

C. Pig

D. Hive

E. Oozie

F. Flume

G. Sqoop

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?

A. Increase the block size on all current files in HDFS.

B. Increase the block size on your remaining files.

C. Decrease the block size on your remaining files.

D. Increase the amount of memory for the NameNode.

E. Increase the number of disks (or size) for the NameNode.

F. Decrease the block size on all current files in HDFS.

Which best describes what the map method accepts and emits?

A. It accepts a single key-value pair as input and emits a single key and list of corresponding values as output.

B. It accepts a single key-value pairs as input and can emit only one key-value pair as output.

C. It accepts a list key-value pairs as input and can emit only one key-value pair as output.

D. It accepts a single key-value pairs as input and can emit any number of key-value pair as output, including zero.

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

A. When the types of the reduce operation's input key and input value match the types of the reducer's output key and output value and when the reduce operation is both communicative and associative.

B. When the signature of the reduce method matches the signature of the combine method.

C. Always. Code can be reused in Java since it is a polymorphic object-oriented programming language.

D. Always. The point of a combiner is to serve as a mini-reducer directly after the map phase to increase performance.

E. Never. Combiners and reducers must be implemented separately because they serve different purposes.