Top 50+ AWS Interview Questions

Amazon Web Services (AWS) is an emerging technology used by many organisations globally. According to Statista, Amazon dominates the cloud market with a 32% market share, which denotes the rapid growth of this technology. Therefore, a career in AWS can be very rewarding and promising. There is a high demand for professionals who are experienced in this platform.

If you are a beginner in this field, you may feel confused thinking about how to crack an Amazon AWS interview. However, what if you have access to the top 50+ most asked AWS Interview Questions? Read this blog to learn the top 50+ AWS Interview Questions and answers for newbies and professionals. This will certainly help you crack the Interview. Let’s dive in!

Table of Contents

1) Basic AWS Interview Questions and Answers

2) Technical AWS Interview Questions and answers

3) Scenario-based AWS Interview Questions

4) Behavioural and situation-based AWS Interview Questions

5) Conclusion

Basic AWS Interview Questions and Answers

These are basic questions that deal with some commonly used terms and concepts about AWS. Read more to learn those AWS basic Interview Questions and answers:

1) What is AWS?

AWS is a Cloud Computing platform offered by Amazon. It provides several cloud services that let you create, deploy, and manage infrastructure and applications in a flexible, scalable, and economical way.
 

 

2) What is Cloud Computing?

Cloud Computing is a service that provides computing resources like storage, processing power, etc., over the internet. It is meant to break the barriers like hardware requirements and physical space needed for scaling up your business.

3) What is the maximum number of subnets you can have per Virtual Private Cloud (VPC)?

A VPC can have up to 200 subnets.

4) What is PaaS?

Platform-as-a-Service (PaaS) is an environment that lets users' provision, control and run resources over the internet.

5) What are the services of AWS?

AWS has many services, and organisations can leverage these services and access resources as needed, paying only for what they use. Some of the AWS services are listed below:

a) Compute power

b) Storage

c) Databases

d) Networking

e) Machine Learning

f) Analytics

6) What year did EC2 officially launch?

It officially launched in the year 2006.

7) Explain what edge locations are in simple terms.

 They are data centers used to reduce latency and rapidly deliver services.

8) What is a subnet?

In layman’s terms, subnets are a huge group of IP addresses broken down into smaller chunks.

9) What are the important components of AWS?

AWS has a variety of components that can handle the workload of any business. Here are the key components of AWS:

a) Elastic Compute Cloud: This is a web service used to provide flexible computing capabilities in the cloud.

b) Elastic Block store: It is used to store continuous data for EC2 instances on the cloud.

c) Simple Storage Service: It is a service used for storage and offers virtually infinite storage.

d) Identity Access Management: It is a feature used to provide and control access to the cloud.

e) Route 53: It is a web-based Domain Name System (DNS) that connects AWS applications with users.

f) Simple Email Service: It is a cloud-based email service that can connect with other applications to send bulk emails.

g) CloudWatch: It is used to observe and track applications and resources on the cloud and on-premises.

10) Can you connect EBS volume to multiple instances?

No, it is not possible to connect EBS volumes to multiple instances. However, you can connect several EBS volumes to a single instance.

11) Explain what Amazon Kinesis Firehose is and what it is used for.

It is a web-based service used for streaming live data to various storage services like Amazon Redshift and Amazon S3.

12) What is the limit size of SQS messages?

The peak limit of message size in SQS is 256 Kilobytes.

13) What is the peak size and minimum size for storing an object in S3?

You can store objects starting from a minimum of zero bytes to a maximum of up to 5 TB.

14) What is EC2, and what can you do with it?

EC2, or Amazon Elastic Compute Cloud, is a web service that offers scalable computing capability in the cloud. You can use it to construct and manage virtual servers, also referred to as EC2 instances, in various ways. You can have complete control over the setup and maintenance of EC2 instances. Moreover, you can use these instances on various Operating Systems.

It allows for flexible scaling of compute resources in response to demand. So, it is perfectly suitable for hosting applications, carrying out batch operations, and carrying out other performance-intensive tasks.

15) What is S3 in AWS?

Amazon S3 is a service that offers leading durability, scalability, and security for storing and retrieving data. It provides an uncomplicated web services interface to store and retrieve data from the internet.

S3 is commonly used for backup, data archiving and restoring, content distribution, media storage, hosting static websites, etc. It offers features such as versioning, lifecycle management, encryption, and access control to efficiently manage data storage.

16) What is RDS?

This is a Relational Database Service that simplifies the deployment, management, and scaling of Relational Databases in the cloud. Amazon RDS supports popular database engines such as MySQL, PostgreSQL, Oracle, SQL Server, and Amazon Aurora.

RDS takes care of routine database tasks such as backups, software patching, and automatic scaling and ensures high availability. So, your developers can focus on their applications rather than database administration.

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17) Explain what Amazon Lambda is and its benefits are.

It is a serverless computing service that lets you run code without the management or provisioning of servers. So, you don’t need any physical hardware to run applications and codes, as AWS Lambda will take care of it. This allows you to execute your code in response to events and automatically scale resources to handle the workload.

Apart from this, it supports multiple programming languages, so you can build applications using various languages and scripts. The best part is you can build applications on a serverless architecture. It has a flexible pay-as-you-go payment model, which requires you to pay only when you consume resources.

This implies you pay only for the total processing time consumed by your codecommit. It is commonly used for event-driven processing, real-time file processing, data transformations, and building microservices.

18) What is Amazon VPC?

The Amazon Virtual Private Cloud or VPC enables you to create a logically isolated virtual network within the AWS cloud. It allows you to define a private IP address range, launch AWS resources like EC2 instances, and connect them to your virtual network.

VPC provides complete control over network configuration, and you can control everything from subnet routing tables to security settings. It also supports Virtual Private Network (VPN) connections, Direct Connect, and network gateways, allowing you to securely connect your VPC to your on-premises infrastructure or other cloud environments.

19) What is the peak limit for creating elastic IPs per AWS account?

You can create up to five elastic IP addresses per AWS account.

20) What are T2 instances, and what is their purpose?

They are general-purpose instances created to boost performance and handle high workloads.

21) What is Amazon EMR, and what are its use cases?

Amazon EMR is a cloud-based big data solution primarily used for performing high-volume tasks like data processing and other data-intensive tasks. Here are the use cases of Amazon EMR:

a) Useable for big data analytics

b) Build expendable data pipelines

c) Use it for speeding up Machine Learning and data science

d) You can use it for analysing large data sets

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22) What is the relation between the Availability Zone and Region?

Availability Zones (AZs) and Region refer to the physical locations of the AWS Architecture and infrastructure facilities. Regions refer to geographical locations like UK North 1 (Scotland) and US South 5 (Texas) and consist of multiple AZs. Availability Zones are isolated data centres within a region and provide redundancy and fault tolerance. 

Deploying resources across AZs ensures high availability and resilience to failures. Moreover, deploying resources across different regions further enhances disaster recovery.

23) How do you upgrade or downgrade a system with near-zero downtime?

Upgrading or downgrading a system with near-zero downtime includes thorough planning, execution, and, often, a combination of strategies. Here are the key steps to achieve this:

1) Access EC2 console: Begin by accessing the EC2 console, which provides you with control over your cloud-based Virtual Machines.

2) Select Operating System AMI: Choose the appropriate Amazon Machine Image (AMI) that corresponds to your desired system configuration. Ensure it matches the target system, whether you're upgrading or downgrading.

3) Launch a new instance: Launch a new instance using the selected AMI. This new instance will represent your updated system configuration.

4) Apply updates: Once the new instance is up and running, apply all necessary updates to the Operating System. This makes sure that the system is using the latest software and security patches. 

5) Install applications: Install the required applications and components onto the new instance. This step makes sure that your system functions as expected with the updated configuration.

6) Testing: Conduct thorough testing to verify that it operates correctly before fully deploying the new instance. Make sure that all applications and services function without issues.

7) Deployment and replacement: If the testing phase is successful and the new instance's performance is satisfactory, you can proceed with deploying it.

8) Upgrade or downgrade: Once the new instance is successfully deployed, your system is upgraded or downgraded with minimal downtime. This transition is seamless, and your users can continue to interact with the system without significant disruptions.

By following these well-structured steps, you can efficiently upgrade or downgrade your system while maintaining near-zero downtime, ensuring a smooth and uninterrupted User Experience.

24) What is a DDoS attack, and what services can minimise them?

A Distributed Denial of Service (DDoS) attack is a Cyber Security Attack in which the attacker gains access to a website or online service. The attacker then floods it with a massive volume of requests, overwhelming the server's capacity. This flood of requests is typically generated from multiple compromised devices or computers. 

This makes it extremely difficult to identify and mitigate the attack. The aim of a DDoS attack is to disrupt the normal operation of a website or service, rendering it temporarily or completely unavailable to legitimate users. Let’s explore the AWS services that can help you prevent such attacks:

1) Virtual Private Cloud (VPC): Implementing a well-architected VPC can enhance your security posture against DDoS attacks.

2) Amazon CloudFront: Amazon CloudFront is a Content Delivery Network (CDN) service that can help mitigate DDoS attacks by distributing and delivering content from various edge locations.

3) Amazon Route 53: Amazon Route 53 is a scalable and highly available Domain Name System (DNS) web service.

4) Elastic Load Balancing (ELB): ELB plays a crucial role in DDoS mitigation by distributing incoming application traffic across multiple targets or instances. 

5) AWS Web Application Firewall (WAF): It enables you to configure rules to filter out malicious traffic, safeguarding your web applications from unwanted access.

6) AWS Shield: Amazon Web Services Shield safeguards AWS Applications  and resources from large and sophisticated attacks.

Technical AWS Interview Questions and Answers

Now, you will learn the technical interview questions. Here are the technical AWS Interview Questions and answers.

25) Is vertical scaling allowed in the Amazon instance?

Yes, it is allowed, and you can vertically estimate an Amazon instance.

26) What is needed to use peering connections?

You need the internet gateway to use peering connections.

27) What is Geo restriction in CloudFront?

It is a tool that can prevent users of specific locations from accessing your content.

28) Does Amazon VPC support multicast and broadcast?

No, it doesn’t have support for multicast and broadcast.

29) Explain what key pairs are and what their purpose is.

They are sensitive and secure information necessary for logging in to your Virtual Machines. You need to use key pairs in order to connect to the instances.

30) What are the different EC2 instance types?

A large variety of instance types tailored for various workloads are available on EC2. Several popular EC2 instance types are:

1) General purpose instances: It offers a balance between various resources like computing, memory, and networking, and you can use it for different work requirements.

2) Memory optimised instances: These instances are created and optimised for tasks that require a high amount of memory.

3) Storage optimised instances: These instances are capable of handling tasks that require sequential and high read/ write capable data sets.

4) Compute optimised instances: These instances are perfect for handling workloads that require high computation power.

31) What is auto-scaling, and how does it work?

When launching or terminating instances, auto-scaling applies scaling policies based on indicators like CPU utilisation, network traffic, or custom metrics. Moreover, it dynamically adds or removes instances from an auto-scaling group when the set conditions are met. This helps ensure the necessary number of instances is always available.

32) How would you deploy an application on AWS?  

You can deploy applications on Virtual Machines using a service called AWS CodeDeploy, which will be handled by EC2. It also helps automate this on the cloud or even on an on-premise server.  

33) How do you secure data in Amazon S3?

From IAM to encryption, you can use a number of security methods to secure data in Amazon S3. Some of these methods are explained below:

a) Access control: You can use Identity and Access Management (IAM) to set permissions and control access to S3 objects and buckets.

b) Bucket policies: You can restrict and control access by implementing security policies at the bucket level.

c) Access logging: You can use this to observe and track any unauthorised access to data.

d) Encryption: You can use S3’s various encryption methods, like Server-Side Encryption (SSE) and managed keys, to secure data.

e) Network security: You can use a Virtual Private Cloud (VPC) and set bucket policies to secure data at a network level.

f) Cross-Region Replication: It helps secure data by having backups of your data across various regions.

34) Explain the Glacier storage service.

Glacier is intended for long-term storage of rarely accessed data. For backup, archive, and regulatory compliance needs, it provides a highly secure and cheap storage option.

35) What is Amazon EBS, and how does it operate?

EBS or Elastic Block Store helps you enhance the performance of your storage and reduce costs. It lets you build storage volumes and pack them into EC2 instances.

36) How can you achieve high availability in EC2?

You can use the following tactics to achieve high availability in EC2:

a) Availability Zones (AZs): In order to ensure redundancy and fault tolerance, you can deploy EC2 instances across different AZs. AZs are standalone data centre facilities with their own networking, power, and cooling systems.

b) Auto Scaling: Create an Auto Scaling group and configure it to launch and shut down EC2 instances according to demand. By doing this, even if some instances fail, the desired number will always be accessible.

c) Elastic Load Balancing: Use Elastic Load Balancers (ELBs) to distribute incoming traffic among many EC2 instances. The ELB reroutes traffic to the remaining healthy instances if an instance goes down.

d) Database replication: Implement database replication over several availability zones to ensure data availability and durability even in the event of a failure.

37) What is the difference between AWS Snowball, Snowmobile, and Snowball Edge?

Snowball is a service used to transfer large volumes of data in and out of a particular AWS region. In contrast, Snowmobile is a migration solution that can perform exabyte-scale data transfer of up to 100 Petabytes (PB). Snowball Edge has data transfer capabilities as well as the ability to compute functions.

38) What is Snowball?

It is an application used for transferring high volumes of data both inside and outside of the AWS environment. Snowball is capable of handling terabytes of data.

39) What is Amazon RDS, and what are its benefits?mazon RDS, and what are its benefits?

Amazon RDS (Relational Database Service) is a managed database service provided by AWS. It eases the process of setting up, operating, and scaling relational databases in the cloud. The following are its benefits:

a) Easy setup: It is very easy to deploy and configure popular database engines.

b) Scalability: You can scale up resources based on the needs of your application.

c) High availability: It has many built-in features that ensure high availability and high fault tolerance.

d) Performance monitoring: It helps optimise performance by identifying bottlenecks.

e) Security: It has many tools like IAM for managing user access to ensure security.

40) What are the different database engines supported by RDS?

Amazon RDS supports several popular database engines, and some of them are listed below:

a) Amazon Aurora (compatible with MySQL and PostgreSQL)

b) PostgreSQL

c) MariaDB

d) Oracle Database

e) Microsoft SQL Server

41) Explain the differences between EC2 and S3.

S3 is a service that is used for storage and can store virtually unlimited data. It uses the Rest interface, is considered very secure, and uses HMAC-SHA1 authentication keys for verification. EC2 is a versatile Virtual Machine that can run on various Operating Systems like Linux and Windows. Moreover, it is also capable of running programs like Python, Apache, PHP, etc.

42) How can you connect multiple VPCs?

You can connect multiple VPCs using VPC peering.

43) What is the average boot time, for instance, stored backend AMI?

It usually takes five minutes or even less time to boot instances stored in the backend AMI.

44) Name the different storage classes of Amazon S3.

There are four different storage classes of Amazon S3, and they are listed below:

a) Amazon Glacier

b) Amazon S3 Reduced Redundancy Storage

c) Amazon S3 Standard-Infrequent Access

d) Amazon S3 standard

45) How many S3 buckets can be created?

By default, you can create up to 100 S3 buckets per AWS account by default. Each bucket you create must have a unique name within the AWS region. However, you can request an increase in this limit by contacting AWS support if needed. AWS support can evaluate your request and make adjustments accordingly.

46) What are Solaris and AIX Operating Systems? Are they available with AWS?

Solaris is an Operating System developed by Sun Microsystems and is now owned by Oracle Corporation. It's based on the Unix Operating System and is known for its scalability and reliability. Solaris is commonly used in enterprise environments and data centres for tasks like running web servers, databases, and various applications. It is not available on AWS at the moment.

Advanced Interactive Executive (AIX) is an Operating System developed by IBM. It's another Unix-based OS known for its robustness and scalability. AIX is often used in large enterprises, especially those relying on IBM hardware, and is suitable for various tasks, including database management and high-performance computing. For the time being, it is also not available on AWS.

47) How do you configure CloudWatch to recover an EC2 instance?

Configuring Amazon CloudWatch to recover an EC2 instance can be done using AWS Auto Scaling. Let's explore the key steps involved in it:

1) Create CloudWatch alarms: Go to the CloudWatch service in the AWS Management Console. Create one or more CloudWatch alarms that monitor the health and performance of your EC2 instances. For example, you can create an alarm to watch CPU utilisation, network traffic, or any custom metrics you need on your AWS Projects. Set the alarm thresholds based on the conditions that will trigger the need for recovery.

2) Configure Auto Scaling policies: Within the Auto Scaling group settings, create scaling policies based on the alarms. Set up a "Scale Out" policy to add instances when a specific alarm threshold is breached, indicating the need for more capacity. Create a "Scale In" policy that removes instances when another alarm threshold is triggered, indicating that resources should be reduced.

3) Define the desired behaviour: Configure the scaling policies to determine the desired behaviour. For example, you can specify how many instances to add or remove when the alarms trigger.

4) Attach Alarms to a group: Associate the CloudWatch alarms you created with the Auto Scaling group. This linkage will instruct AWS to monitor the specified conditions.

5) Testing and monitoring: It's essential to test and monitor the setup to ensure that it works as intended. Test different scenarios and ensure the alarms trigger the expected scaling actions.

By following these steps, you can configure CloudWatch and Auto Scaling to automatically recover an EC2 instance when set conditions are met.

48) Is there a way to upload a file that is greater than 100 megabytes on Amazon S3?

Yes, it is possible to upload files greater than 100 megabytes on Amazon S3. Users can leverage Amazon S3's Multipart Upload feature, which divides large files into smaller parts and uploads them in parallel. Once all the parts are uploaded, they are combined into a single object. This approach not only allows for the upload of large files but also provides fault tolerance and resuming capabilities in case of interruptions. 

Users can initiate multipart uploads using AWS SDKs, AWS Command Line Interface (CLI), or third-party tools. This makes it a flexible and efficient solution for handling large file uploads to Amazon S3.

49) How many buckets can you create in AWS by default?

You can create up to 100 S3 buckets per AWS account by default. However, you can increase this limit by contacting AWS support if your use case requires more buckets.

Scenario-based AWS Interview Questions

The following questions are scenario-based, where you will be expected to answer questions based on practical scenarios:

50) Consider a scenario where you are running an application using an EC2 instance, and the CPU consumption on your instance crosses over 85 per cent. How will you reduce the load, and what is your strategy?

You can reduce the load by creating an autoscaling group in order to create extra instances. You can then create an application load balancer to route the traffic across these additional instances. This will help significantly reduce the CPU usage.

51) Consider a scenario where your organisation wants to use its domain and email address to receive compliance emails. You need to recommend an easy-to-use and economical service to them. What will be your answer?

You can use Amazon Simple Email Service to receive compliance, which is a cloud-oriented email-sending service that is both simple to use and economical as well.

52) An organisation has a running Web Application Server in the N. Virginia region has a large EBS volume of around 500 GB. Now, the firm needs to migrate its server to another AWS account's London location to meet the business's demands. Which is the best way to migrate the server from the existing location to the London region? What information does the AWS administrator require about AWS A/C?

The best way to migrate the server from the N. Virginia region to another AWS account's London location is as follows:

1) Create an Amazon Machine Image (AMI) of the server that is currently running in the N. Virginia region.

2) Once the AMI is created, the AWS administrator will need the 12-digit account number of the AWS account in the London location. This account number is required to copy the AMI from one AWS account to another.

3) After obtaining the account number, copy the AMI into the London region associated with the second AWS account. In the London region, launch an instance using the copied AMI.

4) Verify that the new instance is running and fully operational in the London region. Ensure that all configurations and data have been successfully transferred.

5) Once the instance in the London region is confirmed to be working correctly, you can proceed to terminate the server in the N. Virginia region.

This migration process ensures that the web application server is moved from one AWS region to another AWS account's region without any significant disruption, and it's a reliable way to handle the migration.

53) A company is currently running a web application with an Amazon RDS MySQL database. Their automated daily backups are not encrypted. A security audit needs future backups to be encrypted and unencrypted backups to be destroyed. The company plans to create at least one encrypted backup before removing the old ones. What steps should they take to ensure encryption for future backups?

In order to enable encryption for future backups of the Amazon RDS MySQL database and satisfy the security audit requirements, the following steps should be taken:

1) Create a snapshot of the existing database used by the organisation.

2) Copy the snapshot to create an encrypted snapshot. This will ensure that future backups are encrypted.

3) After the encrypted snapshot is successfully created, restore the database from this encrypted snapshot.

By following these steps, the company will have enabled encryption for future backups. Moreover, they will also have created at least one encrypted backup before destroying the old, unencrypted backups. Thus, the security audit requirements can be met easily. This approach ensures that data remains secure and compliant with encryption standards.

54) A client reports that they wanted to see an audit log of any changes made to AWS resources in their account. What can the client do to achieve this?

In order to create an audit log of AWS resource changes in their account, the client should enable AWS CloudTrail and set up log delivery to an Amazon S3 bucket. This action records all API calls, ensuring a detailed and secure audit trail for monitoring and auditing AWS resource modifications.

Behavioural and Situation-based AWS Interview Questions  

These questions are designed to test your behaviour and your ability to handle challenges. These questions are a potential game-changer as even if you don’t score well on the technical questions, you could still land a job based on your ability to handle these questions.

55) Describe a complex technical problem you faced and how you solved it.

Here, you need to explain a situation where you faced a serious technical problem and how you solved it. You need to give a real answer where you solve a complex issue using your knowledge and expertise. This helps showcase your skills and your ability to handle challenges.

56) How do you prioritise tasks and handle conflicting deadlines?

Businesses these days are looking for professionals who can get the job done even on tight deadlines. Here, you need to give an answer that could help showcase your productivity and organisational skills, as well as your ability to handle tight deadlines.

57) How do you explain technical terms and concepts to your non-technical peer?

This question is designed to test your mentoring and leadership skills and whether you can guide people or not. Your answer should showcase that you are a cool-headed person who has the knowledge and patience to train people.

58) You have an application running on an EC2 instance. You need to reduce the load on your instance as soon as the CPU utilisation reaches 80 per cent. How will you accomplish the job?

In order to reduce the load on the EC2 instance when its CPU utilisation surpasses 80 per cent, you should implement an autoscaling solution. By creating an autoscaling group, additional instances can be deployed to distribute the increased load effectively. To ensure proper load distribution and high availability, configure an application load balancer and register the EC2 instances as target instances. 

This combination of autoscaling and load balancing helps maintain optimal performance and reliability for your application.

Conclusion

We hope you understood everything about the top 60+ most asked AWS Interview Questions and Answers. These questions and answers can help both beginners and professionals crack the Interview. Wishing you good luck with your Interview!

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