Prepare for your AWS interview with these 30 essential questions covering basic, intermediate, and advanced topics. This guide is designed for freshers, candidates with 1-3 years of experience, and professionals with 3-6 years, featuring conceptual, practical, and scenario-based questions using AWS services.
Basic AWS Interview Questions (1-10)
1. What is AWS and what are its key features?
AWS is a comprehensive cloud computing platform providing over 200 services for compute, storage, databases, networking, and more. Key features include high availability through Regions and Availability Zones, scalability with Auto Scaling, pay-as-you-go pricing, and global infrastructure.[1][7]
2. Explain Regions and Availability Zones in AWS.
A Region is a geographic area like US East (N. Virginia) containing multiple isolated Availability Zones (AZs). AZs are separate data centers within a Region for fault tolerance. For example, us-east-1a and us-east-1b provide redundancy.[1][4][7]
3. What is Amazon EC2?
Amazon EC2 (Elastic Compute Cloud) provides resizable virtual servers in the cloud. You launch instances from Amazon Machine Images (AMIs) to run applications, scaling compute capacity up or down.[3][4]
4. What is Amazon S3?
Amazon S3 (Simple Storage Service) is object storage for durable, scalable data storage. It offers storage classes like Standard, Intelligent-Tiering, and Glacier for different access patterns with 99.999999999% durability.[1][5]
5. What is AWS Lambda?
AWS Lambda is a serverless compute service that runs code in response to events without provisioning servers. You pay only for execution time, supporting languages like Python and Node.js.[5]
6. Differentiate between stopping and terminating an EC2 instance.
Stopping an EC2 instance preserves the instance and its data, allowing restart. Terminating deletes the instance permanently, though EBS root volumes can persist if configured.[3]
7. What is Auto Scaling in AWS?
Auto Scaling automatically adjusts EC2 capacity based on demand, maintaining performance and cost efficiency using scaling policies tied to CloudWatch metrics.[1][5]
8. What are Security Groups in AWS?
Security Groups act as virtual firewalls for EC2 instances, controlling inbound and outbound traffic. By default, all inbound is denied, outbound allowed; rules specify ports like SSH (22) or HTTP (80).[3][5]
9. What is Amazon CloudWatch?
Amazon CloudWatch monitors AWS resources and applications, collecting metrics, logs, and setting alarms. For example, alert on high CPU usage for EC2 instances.[4]
10. What is Amazon RDS?
Amazon RDS is a managed relational database service supporting engines like MySQL, PostgreSQL, and SQL Server. It handles backups, patching, and scaling.[2]
Intermediate AWS Interview Questions (11-20)
11. What is a VPC in AWS and why use it?
A Virtual Private Cloud (VPC) is a logically isolated network for launching AWS resources. It provides control over IP ranges, subnets, routing, and gateways for secure environments.[2][5]
12. Explain IAM in AWS.
AWS Identity and Access Management (IAM) manages users, groups, roles, and permissions. Use policies to grant least-privilege access, like read-only to S3 buckets.[1]
13. What is Amazon CloudFront?
Amazon CloudFront is a content delivery network (CDN) caching content at edge locations to reduce latency. Use it with S3 for static websites or EC2 for dynamic content.[2][1]
14. Differentiate AWS Config and CloudTrail.
AWS Config tracks resource configurations and changes over time. CloudTrail logs API calls and actions for auditing who did what and when.[4]
15. How does Elastic Load Balancing work?
Elastic Load Balancing (ELB) distributes incoming traffic across multiple EC2 instances in Auto Scaling groups. Types include Application Load Balancer (ALB) for HTTP/HTTPS and Network Load Balancer (NLB).[1][2]
16. What is Amazon DynamoDB?
Amazon DynamoDB is a fully managed NoSQL database providing single-digit millisecond latency at any scale. It supports on-demand capacity and global tables.[2]
17. Explain S3 Lifecycle Policies.
S3 Lifecycle Policies automate transitioning objects to cheaper storage classes or expiring them. For example, move logs to Glacier after 30 days.[1][5]
18. What is AWS KMS?
AWS Key Management Service (KMS) manages encryption keys for services like S3 and EBS. It provides server-side encryption with customer-managed keys.[4]
19. How do you set up VPC Peering?
VPC Peering connects two VPCs for private communication using routable CIDR blocks. Create a peering request, accept it, and update route tables.[2]
20. What are Network ACLs (NACLs)?
Network ACLs are stateless firewalls at subnet level, controlling inbound/outbound traffic with numbered rules evaluated in order. Unlike stateful Security Groups.[5]
Advanced AWS Interview Questions (21-30)
21. How would you design high availability for a web application at Zoho?
Deploy EC2 instances in an Auto Scaling group across multiple AZs behind an ALB. Use RDS Multi-AZ for database failover and CloudFront for global content delivery.[2][1]
22. Explain disaster recovery strategies in AWS.
Implement cross-region S3 replication, AMI backups, secondary region VPC with CloudFormation, and database replication via DMS. Test regularly for RPO/RTO compliance.[2]
23. How to optimize costs for an application at Paytm?
Use Reserved/Spot Instances, Auto Scaling, S3 Intelligent-Tiering, and ElastiCache for caching. Monitor with Cost Explorer.[1]
24. What is the AWS Well-Architected Framework?
It evaluates architectures across pillars: Operational Excellence, Security, Reliability, Performance Efficiency, Cost Optimization, and Sustainability using the Well-Architected Tool.[1]
25. Design a data lake architecture using AWS services.
Store raw data in S3, use AWS Glue for ETL, IAM/Lake Formation for security, Athena for querying, Redshift Spectrum for analytics, and QuickSight for visualization.[1]
26. How to achieve fault tolerance in microservices at Salesforce?
Use redundancy across AZs, ALB for traffic distribution, CloudWatch for monitoring, fault isolation, backups, and graceful degradation.[1]
27. Differentiate AWS Direct Connect and VPN.
AWS Direct Connect offers dedicated low-latency private connections. VPN uses public internet over IPsec, easier but with variable performance.[4]
28. What is Amazon EKS?
Amazon Elastic Kubernetes Service (EKS) manages Kubernetes clusters, handling control plane scaling and updates for containerized workloads.[1]
29. Scenario: Handle a sudden traffic spike for Swiggy’s ordering app.
Enable Auto Scaling with CloudWatch alarms on CPU utilization. Use ALB to distribute load and Lambda for serverless burst handling.[1][2]
30. How to secure data in S3 for an Adobe application?
Enable server-side encryption with KMS keys, bucket policies for access, MFA Delete, versioning, and replication for durability.[1][4][5]
