Top 50 AWS Interview Question and Answers
Amazon Web Services (AWS) is one of the leading cloud platforms in the world, offering a wide range of cloud services and solutions. As businesses increasingly shift to the cloud, AWS skills have become highly sought after. If you’re preparing for an AWS interview, this blog post will help you with the top 50 AWS interview questions and answers, covering a broad range of topics from basic to advanced concepts.
1. What is AWS?
Answer: Amazon Web Services (AWS) is a subsidiary of Amazon providing on-demand cloud computing platforms and APIs to individuals, companies, and governments, on a metered pay-as-you-go basis.
2. What are the different types of cloud services offered by AWS?
Answer: AWS provides three main types of cloud services:
- Infrastructure as a Service (IaaS): Offers virtualized computing resources over the internet.
- Platform as a Service (PaaS): Offers hardware and software tools to developers over the internet.
- Software as a Service (SaaS): Delivers software applications via the internet.
3. What is EC2 in AWS?
Answer: Amazon Elastic Compute Cloud (EC2) is a web service that provides scalable computing capacity in the cloud. It allows users to run virtual servers, known as instances, on-demand.
4. Explain the concept of an AMI (Amazon Machine Image).
Answer: An AMI is a pre-configured template for creating a virtual machine within AWS EC2. It includes an operating system, application server, applications, and related configurations.
5. What is an availability zone?
Answer: An Availability Zone (AZ) is a distinct location within an AWS region that is engineered to be isolated from failures in other AZs. It consists of one or more data centers.
6. What is an AWS Region?
Answer: A region is a geographical area containing multiple availability zones. AWS has regions around the world to provide low-latency and high-availability services.
7. What is an Elastic IP?
Answer: Elastic IP (EIP) is a static IPv4 address designed for dynamic cloud computing. It allows you to associate a public IP with an EC2 instance.
8. What is the difference between S3 and EBS?
Answer:
- S3 (Simple Storage Service): Object storage for storing and retrieving any amount of data.
- EBS (Elastic Block Store): Block storage for use with EC2 instances.
9. What is an IAM (Identity and Access Management) role?
Answer: IAM roles allow you to define permissions for entities that you trust, such as users, groups, or AWS services, to access resources in AWS securely.
10. What is AWS Lambda?
Answer: AWS Lambda is a serverless compute service that runs your code in response to events such as changes in data or system states without provisioning or managing servers.
11. What is VPC in AWS?
Answer: Virtual Private Cloud (VPC) allows you to launch AWS resources in a logically isolated network. It helps you control your network configuration, including IP range, subnets, route tables, and network gateways.
12. Explain the concept of subnets in VPC.
Answer: Subnets are subdivisions of an IP network in a VPC. You can create public or private subnets to organize your AWS resources.
13. What is CloudWatch?
Answer: AWS CloudWatch is a monitoring and observability service that provides data and actionable insights for AWS, hybrid, and on-premises applications and infrastructure resources.
14. What is AWS CloudFormation?
Answer: AWS CloudFormation is a service that allows you to model and provision AWS resources in a declarative way using templates.
15. What is the difference between Horizontal and Vertical scaling?
Answer:
- Horizontal scaling (Scaling out/in): Adding or removing instances to/from a pool.
- Vertical scaling (Scaling up/down): Adding or removing resources (like CPU, RAM) to/from an individual instance.
16. What is Auto Scaling in AWS?
Answer: AWS Auto Scaling allows you to automatically adjust the number of EC2 instances in your application’s architecture based on demand.
17. What is the AWS Pricing Calculator?
Answer: The AWS Pricing Calculator helps you estimate the cost of using AWS services based on your usage patterns.
18. What is an ELB (Elastic Load Balancer)?
Answer: ELB automatically distributes incoming application traffic across multiple EC2 instances to ensure high availability and fault tolerance.
19. What is the difference between Application Load Balancer and Network Load Balancer?
Answer:
- Application Load Balancer (ALB): Operates at the application layer (Layer 7) and supports routing based on URL, HTTP headers, etc.
- Network Load Balancer (NLB): Operates at the transport layer (Layer 4) and supports ultra-low latency and TCP traffic.
20. What is Route 53?
Answer: Amazon Route 53 is a scalable Domain Name System (DNS) web service designed to route end-user requests to various AWS resources.
21. What are AWS Security Groups?
Answer: AWS Security Groups are virtual firewalls that control inbound and outbound traffic to AWS resources such as EC2 instances.
22. What is AWS RDS?
Answer: Amazon Relational Database Service (RDS) is a managed service that makes it easy to set up, operate, and scale relational databases in the cloud.
23. What is DynamoDB?
Answer: Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability.
24. What is the difference between DynamoDB and RDS?
Answer:
- DynamoDB: NoSQL database, best for unstructured data and high-speed operations.
- RDS: Relational database, best for structured data and complex queries.
25. What is the difference between AWS S3 and AWS Glacier?
Answer:
- S3: Designed for frequently accessed data with low latency.
- Glacier: Designed for long-term archival storage with retrieval times ranging from minutes to hours.
26. What is the AWS Shared Responsibility Model?
Answer: The model outlines the security responsibilities of AWS and the customer. AWS is responsible for security of the cloud (hardware, software, and network), while the customer is responsible for security in the cloud (data, identity, and access management).
27. What is AWS Snowball?
Answer: AWS Snowball is a data transport solution that helps to move large amounts of data into and out of AWS using secure physical devices.
28. What is the AWS Well-Architected Framework?
Answer: The AWS Well-Architected Framework helps you design, build, and maintain well-architected solutions. It provides best practices across five pillars: operational excellence, security, reliability, performance efficiency, and cost optimization.
29. What is Amazon SQS?
Answer: Amazon Simple Queue Service (SQS) is a fully managed message queuing service that allows decoupling and scaling microservices, distributed systems, and serverless applications.
30. What is Amazon SNS?
Answer: Amazon Simple Notification Service (SNS) is a fully managed pub/sub messaging service that allows you to send messages to a large number of subscribers.
31. What is AWS Elastic Beanstalk?
Answer: AWS Elastic Beanstalk is a Platform-as-a-Service (PaaS) offering that enables developers to quickly deploy and manage applications without having to manage the infrastructure. It supports multiple programming languages, including Java, .NET, PHP, Node.js, Python, and more.
32. What is AWS S3 Versioning?
Answer: S3 Versioning allows you to preserve, retrieve, and restore every version of every object stored in an S3 bucket. This helps to protect data from accidental deletion or overwrite.
33. What is AWS Glacier Vault Lock?
Answer: AWS Glacier Vault Lock provides a way to enforce compliance controls on your Glacier vaults by locking the policy so that it cannot be modified or deleted for a specified period.
34. What is Amazon CloudFront?
Answer: Amazon CloudFront is a Content Delivery Network (CDN) service that distributes content globally with low latency and high transfer speeds. It integrates with AWS services like S3, EC2, and Elastic Load Balancer.
35. What are the different types of EBS volumes?
Answer: AWS offers several types of EBS volumes, including:
- General Purpose SSD (gp3/gp2): Balanced price/performance.
- Provisioned IOPS SSD (io1/io2): High-performance SSD for critical applications.
- Throughput Optimized HDD (st1): Low-cost HDD for frequently accessed data.
- Cold HDD (sc1): Low-cost HDD for infrequent access.
36. What is AWS WAF?
Answer: AWS Web Application Firewall (WAF) helps protect your web applications from common web exploits like SQL injection, cross-site scripting (XSS), and others that could affect your application’s availability, security, or performance.
37. What is AWS Direct Connect?
Answer: AWS Direct Connect is a network service that establishes a dedicated network connection from your on-premises data center to AWS, improving bandwidth, reducing latency, and offering more consistent network performance.
38. What is the difference between Stateful and Stateless applications?
Answer:
- Stateful: Maintains session information and state between client and server.
- Stateless: Does not retain session information, and every request is independent.
39. What is the difference between AWS SQS and SNS?
Answer:
- SQS (Simple Queue Service): Used for message queuing where messages are stored until retrieved by the consumer.
- SNS (Simple Notification Service): Used for pub/sub messaging where messages are pushed to multiple subscribers.
40. What is AWS X-Ray?
Answer: AWS X-Ray is a service that helps developers analyze and debug production applications, particularly those built using microservices. It provides end-to-end visibility into requests as they travel through the application.
41. What is Amazon Kinesis?
Answer: Amazon Kinesis is a platform for streaming data on AWS that allows you to collect, process, and analyze real-time, streaming data such as video, audio, application logs, and more.
42. What is Amazon Redshift?
Answer: Amazon Redshift is a fully managed data warehouse service that allows you to run complex queries and analytics on large datasets. It is optimized for handling petabytes of data.
43. What is AWS Glue?
Answer: AWS Glue is a fully managed ETL (Extract, Transform, Load) service that helps you prepare and transform data for analytics by automating data movement and transformation.
44. What is the AWS Free Tier?
Answer: The AWS Free Tier provides limited free usage of AWS services for new AWS customers for the first 12 months after account creation. It includes free usage for services like EC2, S3, Lambda, and RDS.
45. What is the difference between AWS Lambda and EC2?
Answer:
- AWS Lambda: Serverless computing where you upload your code, and AWS takes care of provisioning and scaling the infrastructure automatically.
- EC2: Infrastructure-as-a-Service (IaaS) where you manually provision and manage virtual servers.
46. What is AWS Trusted Advisor?
Answer: AWS Trusted Advisor is an online resource to help AWS customers reduce cost, increase performance, and improve security by providing recommendations across five categories: cost optimization, performance, security, fault tolerance, and service limits.
47. What is Amazon Aurora?
Answer: Amazon Aurora is a fully managed relational database engine that is compatible with MySQL and PostgreSQL. It offers improved performance and reliability at a lower cost compared to traditional databases.
48. What is an AWS Lambda function?
Answer: An AWS Lambda function is a snippet of code that runs in response to events. Lambda functions are event-driven and fully managed, meaning AWS automatically handles the infrastructure and scaling.
49. What is the difference between AWS KMS and AWS CloudHSM?
Answer:
- AWS KMS (Key Management Service): A fully managed service that makes it easy to create and control encryption keys for your applications and data.
- AWS CloudHSM: A hardware security module (HSM) service that enables you to generate and manage your own encryption keys using dedicated hardware.
50. What is Amazon Elastic File System (EFS)?
Answer: Amazon Elastic File System (EFS) is a scalable, fully managed file storage service that can be used with Amazon EC2 instances. It provides a simple, scalable, and elastic file system for Linux-based workloads.
