How to prepare for a Hadoop Interview?

3 years ago only handful of companies were using Hadoop. Now Hadoop technology has grown leaps and bounds so as its user base. Companies from almost all domains have started investing in Big Data technologies. Because of this, we see a steep increase in the number of openings in the Big Data or Hadoop space. With this increase in demand for Hadoop professionals we also see Hadoop interviews maturing a lot. We see a lot of complex, scenario based, analytical questions asked in the Hadoop interviews. It has become absolutely necessary for a beginner or an experienced Hadoop professional to be technically prepared before they show up to an interview.


Hadoop interviews are very different from other technical interviews. If you are interviewing for a Java developer position you will come across a lot of technical questions in Java and very little about the use case of your project and the infrastructure. In Hadoop interviews equal emphasis is given to the use case, infrastructure and the technical aspects of the Hadoop related tools used by you.


The first question you most likely hear in a Hadoop interview is to talk about how you used Hadoop in your recent project. How you answer this question explains a lot about your understanding of the Hadoop framework. Have good answers to explain why your client or company decided to use Hadoop to solve key issues or use cases. Give a concrete use case and explain why it was harder to solve the problem using traditional approach like RDBMS and explain how you solved the problem using Hadoop.


Know about your cluster. Interviewers are very interested to know about your cluster and how it was managed. You will hear questions from cloud services like AWS and your familiarity with it. It is a good idea to prepare for this question in advance. Make sure you know the number of nodes, data volume, replication factor, block size, number of mappers and reducers per node, memory allocated to the mappers and reducers, distribution used etc.


Next comes your role in the project. Question like – Did you involve in the initial design and sizing of your Hadoop cluster? This is a common question even if you are not applying for an architect position. Then comes the list of Hadoop ecosystem tools you are familiar with. At this point technical questions starts to trickle down. Scenario based questions are very common at this point. Often questions are asked based on a scenario or problem which the interviewer faced in the past and will be interested to see how you solve the problem.


Troubleshooting and optimizations questions are very common in Hadoop interviews. Most interviewees unfortunately fail at this point not because they are not familiar or worked on troubleshooting and optimizations related problem but because of their lack of preparation in this topic. Take a look at our sample questions and answers from our Hadoop Developer Interview Guide to get an idea of the questions and answers asked in Hadoop Developer interviews.

From our experience when interviewees try to come up with answers on the fly it never usually works out. Practice and preparing your answers for challenging questions in advance before your Hadoop interviews is key to success.

Good Luck !!!

This is a 2 post series. Now you have an idea of how to approach a Hadoop Interview, go to How to prepare for a Hadoop Interview (Part-2)? which will walk you step by step on what to prepare and how you can structure your interview preparation process.

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