Requirements for distributed application that periodically processes large volumes of data across multiple Amazon EC2 Instances

Question

I had given a DevOps interview but was asked a lot of questions about aws which I was not able to answer. I wanted to get the answers to one of those questions which I did not get on a google search

Q. You have a distributed application that periodically processes large volumes of data across multiple Amazon EC2 Instances. The application is designed to recover gracefully from Amazon EC2 instance failures. You are required to accomplish this task in the most cost-effective way.

Which of the following will meet your requirements?

• A. Spot Instances
• B. Reserved instances
• C. Dedicated instances
• D. On-Demand instances

Answer 1

Hey @Greg, you should always do some research about the company and what technologies and software they are using before going for the interview. Obviously, they will not just require one technology(DevOps). Its always a combination and the most famous combination is AWS and DevOps.

The answer to your question is A.

Since the work we are addressing here is not continuous, a reserved instance shall be idle at times, same goes with On-Demand instances. Also, it does not make sense to launch an On-Demand instance whenever work comes up since it is expensive. Hence Spot Instances will be the right fit because of their low rates and no long term commitments.

Also, have a look at this AWS interview questions article for more such questions.