How to Dominate Your Apache Cassandra Interview

Posted by Jeff Pelliccio on Jan 15, 2018 9:00:00 AM

In Interview Tips

Because Apache Cassandra positions are (and are likely to remain) one of the most in-demand positions in the tech world today, the impression that you're able to make during your interview is of critical importance. To say that you're going to have a lot of competition is a bit of an understatement, which means that you need to do more than just "do well." You need to dominate, leaving the type of lasting impression that any staffing agency professional or IT staffing recruiter won't soon forget.

To do that, prepare yourself for the interview by reviewing the best answers to some of the most common questions you're likely to face.

1. "What, in your opinion, are the major benefits of Apache Cassandra?"

This question can be a tricky one, as the benefits are so extensive that you run the risk of getting lost in the details of your own answer. For the best results, focus on the benefits that relate directly to the specific position you are applying for.

In general, the major advantage of Apache Cassandra is it delivers almost real-time performance while simplifying the daily work of Developers, Data Analysts, Software Engineers and every in between at the exact same time. Because Cassandra is built on a peer-to-peer architecture, failure is virtually eliminated. Likewise, it offers an almost unparalleled level of flexibility as multiple nodes can be inserted into any Cassandra cluster in any data center. Along the same lines, any client can forward its request to any server at all times.

2. "Why should we be using Apache Cassandra in the first place?"

Again, this one is a bit tricky as it naturally overlaps with any variation of the previous question that you're likely to be asked. Focus on the bigger implications of this question, discussing things like Cassandra's fault tolerance and consistency, along with its gigabytes to petabytes scalabilities

You'll also want to lean into just how flexible Apache Cassandra is, as this is one of the qualities that gives organizations room to continue to grow and evolve in naturally fluid environments. Cassandra not only has a flexible schema design, but it also offers flexible data storage, effortless data distribution, and fast writes as well.

3. "How would you explain the idea of Tunable Consistency?"

One of the recurring themes that you'll likely notice during your interview is that you'll be asked general topic-centric questions like this one in an effort to make sure that you really do possess the skills and knowledge that your resume says you do. In terms of Tunable Consistency, it's the concept that refers to the up-to-date and synchronized data rows (and their replicas) that Apache Cassandra allows for. 

Be sure to go into detail about Eventual Consistency (which guarantees consistency in situations when no new updates are made on any particular item in a database) and Strong Consistency (which relates to the condition R + W > N).

4. "What are the major components of the Cassandra Data Model?"

This is another general knowledge question, but thankfully it's also a straightforward one. The main components of any Cassandra Data Model include the cluster, the keyspace, the column, and the column & family.

If the interviewer presses you to continue, be sure to mention other components like nodes, data centers, clusters, commit logs and mem-tables.

5. "What do you know about CAP Theorem?"

As stated, flexibility and scalability are two of the most important benefits of Apache Cassandra to any organization - which means that you can all but guarantee you'll be asked about CAP Theorem during your interview.

At its core, CAP (short for "Consistency Availability and Partition") Theorem is an efficient way to address the need to scale in distributed systems. Essentially, it means that you can only have access to two out of three major characteristics at any given time - Consistency, Availability and Partition. Which of these three qualities is sacrificed given the demands of the situation will play a critical role in the development of a scaling strategy moving forward.

In a lot of ways, it's a bit like the old saying "you can have something fast, cheap or good - pick two."

Going Beyond the Questions

Any staffing agency professional or IT staffing recruiter will tell you that your ability to answer questions correctly during your Apache Cassandra interview is simply one small part of a much larger story. Yes, it's very important, and yes, you should prepare - but your personality will also play an important role in determining whether or not you land that position you're after.

Resist the urge to rest on the fact that you know the answers to the questions you're about to be asked and don't be afraid to let your true personality shine. Remember, recruiters don't just want to know that you're competent during an interview - they also want to see if you're the type of person they actually want to work with on a daily basis. If you're able to manage the delicate balance between these two concepts, you will go far. 

ICS helps place countless professionals in roles that fit their skills, talent, and personalities. If you need any help finding a job or getting your foot in the door, we are here for you. Your next job could be your dream job so make sure you apply today. 

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