Hadoop Interview Questions and Answers

Ques 1. What is Hadoop?

Hadoop is a distributed computing platform. It is written in Java. It consists of the features like Google File System and MapReduce.

Ques 2. What platform and Java version are required to run Hadoop?

Java 1.6.x or higher versions are good for Hadoop, preferably from Sun. Linux and Windows are the supported operating system for Hadoop, but BSD, Mac OS/X, and Solaris are more famous for working.

Ques 3. What kind of Hardware is best for Hadoop?

Hadoop can run on a dual processor/ dual core machines with 4-8 GB RAM using ECC memory. It depends on the workflow needs.

Ques 4. What are the most common input formats defined in Hadoop?

These are the most common input formats defined in Hadoop:

1. TextInputFormat
2. KeyValueInputFormat
3. SequenceFileInputFormat

TextInputFormat is a by default input format.

Ques 5. How do you categorize a big data?

The big data can be categorized using the following features:

• Volume
• Velocity
• Variety

Ques 6. Give the use of the bootstrap panel.

We use panels in bootstrap from the boxing of DOM components.

Ques 7. What is the purpose of button groups?

Button groups are used for the placement of more than one buttons in the same line.

Ques 8. Name the various types of lists supported by Bootstrap.

• Ordered list
• Unordered list
• Definition list

Ques 9. Which command is used for the retrieval of the status of daemons running the Hadoop cluster?

The 'jps' command is used for the retrieval of the status of daemons running the Hadoop cluster.

Ques 10. What is InputSplit in Hadoop? Explain.

When a Hadoop job runs, it splits input files into chunks and assigns each split to a mapper for processing. It is called the InputSplit.

Ques 11. What is TextInputFormat in Hadoop?

In TextInputFormat, each line in the text file is a record. Value is the content of the line while Key is the byte offset of the line. For instance, Key: longWritable, Value: text