11 Essential AWS Interview Questions and Answers (2022)

By Indeed Editorial Team

January 13, 2022

Amazon Web Services (AWS) is a cloud platform to help businesses create applications using features like templates and containers to streamline the development process. Because Amazon is such a prominent name in all types of technology and AWS is a popular platform for several websites and services, it's important that enterprise developers be able to answer AWS interview questions. In this article, you'll learn what to expect in an AWS interview, and we'll offer questions and answers to better help you prepare.

What to expect from an AWS interview?

For those embarking on an AWS, interview expect questions to focus largely around technical skills and experience with the platform. It's highly likely you may be able to provide demonstrable knowledge of AWS and related systems. Questions can range from basic to more complex.

Some questions will be more general and seek to understand how you perform as an AWS developer. You might consider taking an online refresher course on AWS before you and having a portfolio ready with practical examples of your work.

To further exemplify your knowledge of AWS use the STAR method of answering interview questions. STAR asks you to consider a situation where you met an objective or experienced a challenge, define your role in the tasks that resolved the issue, what actions you took and define the overall outcome.

Read more: STAR Method of Answering Interview Questions

Common AWS interview questions and example answers

If you're preparing for an AWS developer interview, consider these AWS interview questions and example answers before you go:

  • What is AWS?

  • Compare and contrast AWS and open stack

  • How can you enhance Elastic Block performance?

  • What's the difference between on-demand and spot instance?

  • If an organization splits their workload between public cloud and private servers, what is this approach called?

  • Explain how to vertically scale an Amazon Instance.

  • In simple terms, explain the difference between vertical and horizontal scaling.

  • What's the number of EC2 instances that can be used in a VPC?

  • What functionality lets you terminate unhealthy instances and replace them with new ones?

  • What skills are important for an AWS developer?

  • Describe a time you used Auto Scaling.

What is AWS?

This is an introductory question that might introduce a longer line of questioning that gets more and more complex with each question. To answer this, provide a detailed definition of AWS and the function it provides.

Example: "AWS is a development platform that makes it easier for businesses to build web-based applications and services. Using AWS allows enterprises to develop secure cloud services with features like database, content delivery, different levels of computational power and more."

Compare and contrast AWS and open stack

Compare and contrast questions are great tools for interviewers because they offer the opportunity to ask about to related entities in one question. If you're answering this question you should define both while stating their similarities and differences.

Example: "AWS and open stack are both development platforms. They have the same type of user interface but different computation (AWS has EC2 and open stack has Nova), file storage (AWS has S3 and open stack has Swift), block storage (AWS has EBS and open stack has Cinder) and networking (AWS has a VPC while open stack does not). Also, AWS supports big data."

How can you enhance Elastic Block performance?

This question asks about a specific feature that might be important to the employer. To prepare for feature-based questions, study AWS coursework or access online resources like this one to better understand concepts in AWS.

Example: "Because performance needs can vary, I like to first establish what the performance level should be. It may be necessary to establish incremental improvements to account for any issues that may arise. Once I understand what the performance should be, I can implement certain software and perform data striping across all volumes. It's also important to review the performance regularly and establish additional protocols if an additional performance enhancement is necessary."

Related: Writing a Technical Resume

What's the difference between on-demand and spot instance?

This question allows you to apply critical thinking to explain nuanced technical concepts by highlighting key differences. You should strive to include a definition of each. You can also use experience to craft part of your answer according to the STAR method of answering interview questions.

Example: "Spot instances provide a lower cost option for developers to manage non-essential tasks on AWS platform. These instances are those you would bid on and they launch once the bid is higher than the going price based on supply and demand. There is a major drawback on spot instances, if the spot exceeds the bid price it can be terminated at any time. On-demand instances are created based on user need and cost by the hour. When they are no longer required, they can be released.

In my experience building services in AWS, I was faced with the challenge of creating a non-essential cloud service that would sync up the phones of delivery drivers for Applico Office Supplied Delivery. Because this was a service that was nice to have but wasn't essential for functioning, I chose a spot-instance. After I developed the service, the result was the drivers were better coordinated and the company saved money."

If an organization splits their workload between public cloud and private servers, what is this approach called?

This question presents a situation that should lead you to a simple, definitive answer. You can be brief in a question that asks you for the name of specific approach. Answer the question clearly and provide a short definition.

Example: "This is a hybrid cloud approach to cloud management."

Related: How To Appear Confident in an Interview

Explain how to vertically scale an Amazon Instance.

This question tests your knowledge of a specific concept in AWS called scaling. There are a number of specifications that could be important to an employer within AWS, so it's good to make sure you have a full understanding of business uses before you interview. To answer this question, provide directions on how to complete vertical scaling that are clear and simple.

Example: "To vertically scale on AWS, start by creating a new, larger instance of AWS, then pause the existing one. While paused, remove and discard the root EBS volume from the server. Now pause the live instance to remove its existing root volume. After making note of the ID number, put the root volume into the new server and restart."

In simple terms, explain the difference between vertical and horizontal scaling

If an interviewer asks you to explain something simply, this provides you the opportunity to do two things. First, you want to correctly answer the question by providing relevant information. Second, you want to explain it in terms that are friendly to people outside of IT.

Example: "Vertical scaling is a growth mechanism by which an existing machine is given more compute power. Horizontal scale occurs when companies grow by adding more machines to their infrastructure."

What's the number of EC2 instances that can be used in a VPC?

This is a basic foundational question that requires a short answer in the form of a value.

Example: "Your instance family can have a maximum of 20 on-demand instances designated for services. Once you hit that limit, you can purchase spot instances if more instances are required."

What functionality lets you terminate unhealthy instances and replace them with new ones?

When an employer asks about specific functions in AWS, it may be a hint this is something important to their business. Do your best to craft a logical, descriptive answer.

Example: "Group Auto Scaling is the feature that allows you to terminate and replace instances."

What skills are important for an AWS developer?

This question allows you to provide insight on your own skills and how they apply to AWS development. You can offer a thoughtful answer with several skills you think are important to bring to the role.

Example: "Essential skills for an AWS developer include C#, Java, Python, advanced computer networking skills, hardware troubleshooting skills, understanding of security features and skills gained from experience with AWS."

Describe a time you used Auto Scaling

This is an excellent opportunity to elaborate on your own experience and share it with your potential employer. Do this by explaining a situation where the Auto Scaling feature offered a solution.

Example: "As a developer for Render, I designed and developed a web service with Auto Scaling. I noticed traffic patterns on the website were highest between 10:30 and 12:30 Monday through Friday. Using Auto Scaling, I was able to configure the service to support more users during peak hours. This resulted in better service delivery to all users."

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