Top Answers to AWS Interview Questions


Amazon AWS comes under the top 15 certifications that individuals enroll in today. It is also among the most popular and high-paying IT jobs in the world. Most professionals are also looking to upskill themselves in this field since major companies have either already transferred their data to the cloud or they are on the verge of doing so. In this blog on Amazon AWS Interview Questions and answers, our aim is to cover all the significant interview questions that are generally asked in the field of the cloud, Amazon AWS, and other related technologies:

Q1. Compare between AWS and OpenStack.
Q2. What is AWS?
Q3. What is the importance of buffer in Amazon Web Services?
Q4. How are Spot Instance, On-demand Instance, and Reserved Instance different from one another?
Q5. Why do we make subnets?
Q6. Is there a way to upload a file that is greater than 100 megabytes in Amazon S3?
Q7. What is the maximum number of S3 buckets you can create?
Q8. How can you save the data on root volume on an EBS-backed machine?
Q9. When should you use the classic load balancer and the application load balancer?
Q10. How many total VPCs per account/region and subnets per VPC can you have?

We have categorized the Top Amazon AWS cloud interview questions into the following three parts:
1. Basic

2. Intermediate

3. Advanced

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AWS Basic Interview Questions

1. Compare between AWS and OpenStack.

Criteria AWS OpenStack
License Amazon proprietary Open source
Operating system Whatever the cloud administrator provides Whatever AMIs provided by AWS
Performing repeatable operations Through templates Through text files

2. What is AWS?

AWS (Amazon Web Services) is a platform to provide secure cloud services, database storage, offerings to compute power, content delivery, and other services to help business level and develop.

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3. What is the importance of buffer in Amazon Web Services?

An Elastic Load Balancer ensures that the incoming traffic is distributed optimally across various AWS instances.  A buffer will synchronize different components and makes the arrangement additionally elastic to a burst of load or traffic. The components are prone to work in an unstable way of receiving and processing requests. The buffer creates an equilibrium linking various apparatus and crafts them work at an identical rate to supply more rapid services.

4. How are Spot Instance, On-demand Instance, and Reserved Instance different from one another?

Both Spot Instance and On-demand Instance are models for pricing.

Spot Instance On-demand Instance
With Spot Instance, customers can purchase compute capacity with no upfront commitment at all. With On-demand Instance, users can launch instances at any time based on the demand.
Spot Instances are spare Amazon instances that you can bid for. On-demand Instances are suitable for high-availability needs of applications.
When the bidding price exceeds the spot price, the instance is automatically launched, and the spot price fluctuates based on supply and demand for instances. On-demand Instances are launched by users only with the pay-as-you-go model.
When the bidding price is less than the spot price, the instance is immediately taken away by Amazon. On-demand Instances will remain persistent without any automatic termination from Amazon.
Spot Instances are charged on an hourly basis. On-demand Instances are charged on a per-second basis

5. Why do we make subnets?

Creating subnets means dividing a large network into smaller ones. These subnets can be created for several reasons. For example, creating and using subnets can help reduce congestion by making sure that the traffic destined for a subnet stays in that subnet. This helps in efficiently routing the traffic coming to the network that reduces the network’s load. Learn more about AWS from this AWS Training in New York to get ahead in your career!

6. Is there a way to upload a file that is greater than 100 megabytes in Amazon S3?

Yes, it is possible by using multipart upload utility from AWS. With multipart upload utility, larger files can be uploaded in multiple parts that are uploaded independently. You can also decrease upload time by uploading these parts in parallel. After the upload is done, the parts will be merged into a single object or file to create the original file from which the parts were created.

7. What is the maximum number of S3 buckets you can create?
  • 50
  • 20
  • 70
  • 100


8. How can you save the data on root volume on an EBS-backed machine?

By overriding the terminate option

9. When should you use the classic load balancer and the application load balancer?

The classic load balancer is used for simple load balancing of traffic across multiple EC2 instances.

Classic Load Balancer


While, the application load balancing is used for more intelligent load balancing, based on the multi-tier architecture or container-based architecture of the application. Application load balancing is mostly used when there is a need to route traffic to multiple services.

Classic Load Balancer

10. How many total VPCs per account/region and subnets per VPC can you have?
  • 4, 100
  • 7, 40
  • 5, 200
  • 3, 150

5, 200

11. Your organization has decided to have all their workload on the public cloud. But, due to certain security concerns, your organization decides to distribute some of the workload on private servers. You are asked to suggest a cloud architecture for your organization. What will be your suggestion?

A hybrid cloud. The hybrid cloud architecture is where an organization can use the public cloud for shared resources and the private cloud for its confidential workloads.

12. Which one of the storage solutions offered by AWS would you use if you need extremely low pricing and data archiving?

Amazon Glacier. AWS Glacier is an extremely low-cost storage service offered by Amazon that is used for data archiving and backup purposes. The longer you store data in Glacier, the lesser it will cost you.

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13. You have connected four instances to ELB. To automatically terminate your unhealthy instances and replace them with new ones, which functionality would you use?

Auto-scaling groups

14. The data on the root volumes of store-backed and EBS-backed instances get deleted by default when they are terminated. If you want to prevent that from happening, which instance would you use?

EBS-backed instances. EBS-backed instances use EBS volume as their root volume. EBS volume consists of virtual drives that can be easily backed up and duplicated by snapshots.

EBS Backed Instances

The biggest advantage of EBS-backed volumes is that the data can be configured to be stored for later retrieval even if the virtual machine or the instances are shut down.

15. How will you configure an Amazon S3 bucket to serve static assets for your public web application?

By configuring the bucket policy to provide public read access to all objects

That is all we have in our section on basic Amazon Web Services interview questions section. Let’s move onto the next section on AWS interview questions for experienced professionals.

Intermediate AWS Interview Questions

16. Your organization wants to send and receive compliance emails to its clients using its own email address and domain. What service would you suggest for achieving the same in an easy and cost-effective way?

Amazon Simple Email Service (Amazon SES), which is a cloud-based email sending service, can be used for this purpose.

17. Can you launch Amazon Elastic Compute Cloud (EC2) instances with predetermined private IP addresses? If yes, then with which Amazon service it is possible?

Yes. It is possible by using VPC (Virtual Private Cloud).

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18. If you launched a standby RDS, will it be launched in the same availability zone as your primary?

No, standby instances are automatically launched in different availability zones than the primary, making them physically independent infrastructures. This is because the whole purpose of standby instances is to prevent infrastructure failure. So, in case the primary goes down, the standby instance will help recover all of the data.

19. Which of the following is a global Content Delivery Network service that securely delivers data to users with low latency and high transfer speed.

Amazon CloudFront

20. Which Amazon solution will you use if you want to accelerate moving petabytes of data in and out of AWS, using storage devices that are designed to be secure for data transfer?

Amazon Snowball. AWS Snowball is the data transport solution for large amounts of data that need to be moved into and out of AWS using physical storage devices.

21. If you are running your DB instance as Multi-AZ deployment, can you use standby DB instances along with your primary DB instance?

No, the standby DB instance cannot be used along with the primary DB instances since the standby DB instances are supposed to be used only if the primary instance goes down.

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22. Your organization is developing a new multi-tier web application in AWS. Being a fairly new and small organization, there’s limited staff. But, the organization requires high availability. This new application comprises complex queries and table joins. Which Amazon service will be the best solution for your organization’s requirements?

DynamoDB will be the right choice here since it is designed to be highly scalable, more than RDS or any other relational database services.

23. You accidently stopped an EC2 instance in a VPC with an associated Elastic IP. If you start the instance again, what will be the result?

The data stored on the instance will be lost. Elastic IP is disassociated from the instance only if the instance is terminated.

24. Your organization has around 50 IAM users. Now, it wants to introduce a new policy that will affect the access permissions of an IAM user. How can it implement this without having to apply the policy at the individual user level?

It is possible using IAM groups, by adding users in the groups as per their roles and by simply applying the policy to the groups.

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Advanced AWS Interview Questions

25. Your organization is using DynamoDB for its application. This application collects data from its users every 10 minutes and stores it in DynamoDB. Then every day, after a particular time interval, the data (respective to each user) is extracted from DynamoDB and sent to S3. Then, the application visualizes this data to the users. You are asked to propose a solution to help optimize the backend of the application for latency at lower cost. What would you recommend?

ElastiCache. Amazon ElastiCache is a caching solution offered by Amazon.

Elastic Cache

It can be used to store a cached version of the application in a region closer to users so that when requests are made by the users the cached version of the application can respond, and hence latency will be reduced.

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26. I created a web application with autoscaling. I observed that the traffic on my application is the highest on Wednesdays and Fridays between 9 AM and 7 PM. What would be the best solution for me to handle the scaling?

Configure a policy in autoscaling to scale as per the predictable traffic patterns.

27. How would you handle a situation where the relational database engine crashes often whenever the traffic to your RDS instances increases, given that the replica of RDS instance is not promoted as the master instance?

A bigger RDS instance type needs to be opted for handling large amounts of traffic, creating manual or automated snapshots to recover data in case the RDS instance goes down.

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28. You have an application running on your Amazon EC2 instance. You want to reduce the load on your instance as soon as the CPU utilization reaches 100 percent. How will you do that?

It can be done by creating an autoscaling group to deploy more instances when the CPU utilization exceeds 100 percent and distributing traffic among instances by creating a load balancer and registering the Amazon EC2 instances with it.

29. What would I have to do if I want to access Amazon Simple Storage buckets and use the information for access audits?

AWS CloudTrail can be used in this case as it is designed for logging and tracking API calls, and it has also been made available for storage solutions.

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30. I created a key in North Virginia region to encrypt my data in Oregon region. I also added three users to the key and an external AWS account. Then, to encrypt an object in S3, when I tried to use the same key, it was not listed. Where did I go wrong?

The data and the key should be in the same region. That is, the data that has to be encrypted should be in the same region as the one in which the key was created. In this case, the data is in Oregon region, whereas the key is created in North Virginia region.

31. Suppose, you hosted an application on AWS that lets the users render images and do some general computing. Which of the below listed services can you use to route the incoming user traffic?
  • Classic Load Balancer
  • Application Load Balancer
  • Network Load balancer

Application Load Balancer: It supports path-based routing of the traffic and hence helps in enhancing the performance of the application structured as smaller services.

Application Load Balancer

Using application load balancer, the traffic can be routed based on the requests made. In this case scenario, the traffic where requests are made for rendering images can be directed to the servers only deployed for rendering images and the traffic where the requests are made for computing can be directed to the servers deployed only for general computing purposes.

32. Suppose, I created a subnet and launched an EC2 instance in the subnet with default settings. Which of the following options will be ready to use on the EC2 instance as soon as it is launched?
  • Elastic IP
  • Private IP
  • Public IP
  • Internet Gateway

Private IP. Private IP is automatically assigned to the instance as soon as it is launched. While elastic IP has to be set manually, Public IP needs an Internet Gateway which again has to be created since it’s a new VPC.

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33. Your organization has four instances for production and another four for testing. You are asked to set up a group of IAM users that can only access the four production instances and not the other four testing instances. How will you achieve this?

We can achieve this by defining tags on the test and production instances and then adding a condition to the IAM policy that allows access to specific tags.

34. Your organization wants to monitor the read and write IOPS for its AWS MySQL RDS instance and then send real-time alerts to its internal operations team. Which service offered by Amazon can help your organization achieve this scenario?

Amazon CloudWatch would help us achieve this. Since Amazon CloudWatch is a monitoring tool offered by Amazon, it’s the right service to use in the above-mentioned scenario.

35. Which of the following services can be used if you want to capture client connection information from your load balancer at a particular time interval?
  • Enabling access logs on your load balancer
  • Enabling CloudTrail for your load balancer
  • Enabling CloudWatch metrics for your load balancer

Enabling CloudTrail for your load balancer. AWS CloudTrail is an inexpensive log monitoring solution provided by Amazon. It can provide logging information for load balancer or any other AWS resources. The provided information can further be used for analysis.

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36. You have created a VPC with private and public subnets. In what kind of subnet would you launch the database servers?

Database servers should be ideally launched in private subnets. Private subnets are ideal for the backend services and databases of all applications since they are not meant to be accessed by the users of the applications, and private subnets are not routable from the Internet.

37. Is it possible to switch from an Instance-backed root volume to an EBS-backed root volume at any time?

No, it is not possible.

38. Can you change the instance type of the instances that are running in your application tier and are also using autoscaling? If yes, then how? (Choose one of the following)
  • Yes, by modifying autoscaling launch configuration
  • Yes, by modifying autoscaling tags configuration
  • Yes, by modifying autoscaling policy configuration
  • No, it cannot be changed

Yes, the instance type of such instances can be changed by modifying autoscaling launch configuration. The tags configuration is used to add metadata to the instances.

39. Can you name the additional network interface that can be created and attached to your Amazon EC2 instance launched in your VPC?

Elastic Network Interface

40. Out of the following options, where does the user specify the maximum number of instances with the autoscaling commands?
  • Autoscaling policy configuration
  • Autoscaling group
  • Autoscaling tags configuration
  • Autoscaling launch configuration

Autoscaling launch configuration

41. Which service provided by AWS can you use to transfer objects from your data center, when you are using Amazon CloudFront?

Amazon Direct Connect. It is a network service that acts as an alternative to using the Internet to connect customers in on-premise sites with AWS.

42. You have deployed multiple EC2 instances across multiple availability zones to run your website. You have also deployed a Multi-AZ RDS MySQL Extra Large DB Instance. The site performs a high number of small read and write operations per second. After some time, you observed that there is read contention on RDS MySQL. What would be your approach to resolve the contention and optimize your website?

We can deploy ElastiCache in memory cache running in every availability zone. This will help in creating a cached version of the website for faster access in each availability zone. We can also add RDS MySQL read replica in each availability zone that can help in efficient and better performance for read operations. So, there will not be any increased workload on RDS MySQL instance, hence resolving the contention issue.

43. Your company wants you to propose a solution so that the company’s data center can be connected to Amazon cloud network. What would be your proposal?

The data center can be connected to Amazon cloud network by establishing a virtual private network (VPN) between the VPC and the data center. Virtual private network lets you establish a secure pathway or tunnel from your premise or device to AWS global network.

44. Which of the following Amazon Services would you choose if you want complex querying capabilities but not a whole data warehouse?
  • RDS
  • Redshift
  • ElastiCache
  • DynamoDB

Amazon RDS

45. You want to modify the security group rules while it is being used by multiple EC2 instances. Will you be able to do that? If yes, will the new rules be implemented on all previously running EC2 instances that were using that security group?

Yes, the security group that is being used by multiple EC2 instances can be modified. The changes will be implemented immediately and be applied to all the previously running EC2 instances without restarting the instances


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46. Which one of the following is a structured data store that supports indexing and data queries to both EC2 and S3?
  • DynamoDB
  • MySQL
  • Aurora
  • SimpleDB


47. Which service offered by Amazon will you choose if you want to collect and process e-commerce data for near real-time analysis? (Choose any two)
  • DynamoDB
  • Redshift
  • Aurora
  • SimpleDB

DynamoDB. DynamoDB is a fully managed NoSQL database service that can be fed any type of unstructured data. Hence, DynamoDB is the most apt choice for collecting data from e-commerce websites.

For near real-time analysis, we can use Amazon Redshift.

48. If in CloudFront the content is not present at an edge location, what will happen when a request is made for that content?

CloudFront will deliver the content directly from the origin server. It will also store the content in the cache of the edge location where the content was missing.

49. Can you change the private IP address of an EC2 instance while it is in running or in a stopped state?

No, it cannot be changed. When an EC2 instance is launched, a private IP address is assigned to that instance at the boot time. This private IP address is attached to the instance for its entire lifetime and can never be changed.

50. Which of the following options will you use if you have to move data over long distances using the Internet, from instances that are spread across countries to your Amazon S3 bucket?
  • Amazon CloudFront
  • Amazon Transfer Acceleration
  • Amazon Snowball
  • Amazon Glacier

Amazon Transfer Acceleration. It throttles the data transfer up to 300 percent using optimized network paths and Amazon Content Delivery Network. Snowball cannot be used here as this service does not support cross-region data transfer.


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51. Which of the following services is a data storage system that also has REST API interface and uses secure HMAC-SHA1 authentication keys?
  • Amazon Elastic Block Store
  • Amazon Snapshot
  • Amazon S3

Amazon S3. It gets various requests from applications, and it has to identify which requests are to be allowed and which to be denied. Amazon S3 REST API uses a custom HTTP scheme based on a keyed HMAC for authentication of requests.

52. What kind of IP address can you use for your customer gateway (CGW) address?

We can use the Internet routable IP address, which is a public IP address of your NAT device.

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53. Which of the following is not an option in security groups?

  • List of users
  • Posts
  • IP addresses
  • List of protocols
  • List of users

Hope these top AWS Interview questions and answers for freshers and experienced helps you in preparing for top AWS jobs in the Cloud market.

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9 thoughts on “Top Amazon AWS Interview Questions - Most Asked”

  1. Thanks for the informative content, please keep on adding new AWS interview questions & answers once you receive it. Would be also good if it is objective-based.

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