Top 50 AWS Interview Questions (With Answers) – WeTechZone Edition

Part 1 – Basic AWS Questions

1. What is AWS? – On‑demand cloud platform offering compute, storage, database, networking and managed services so you do not buy or manage physical servers.
2. Explain regions and availability zones. – Region is a geographic area (like ap-south-1), and each region has multiple AZs which are separate data centres for high availability.
3. What is EC2? – Elastic Compute Cloud. It provides resizable virtual machines where you run applications.
4. What is S3? – Object storage service to store any amount of data with high durability, often used for backups, static websites and logs.
5. What is IAM? – Identity and Access Management service to create users, roles and policies and control who can access which AWS resources.
6. What is an Auto Scaling Group? – A group of EC2 instances that automatically increases or decreases capacity based on demand.
7. What is a security group? – Virtual firewall attached to EC2 instances controlling inbound and outbound traffic at instance level.
8. Difference between Security Group and NACL? – SG works at instance level and is stateful. NACL works at subnet level and is stateless.
9. What is RDS? – Managed relational database service that supports engines like MySQL, PostgreSQL, SQL Server and automatically handles backups and patching.
10. What is CloudWatch? – Monitoring and logging service for metrics, alarms, dashboards and logs.

Part 2 – Intermediate / Associate-Level Questions

11. What is VPC and why is it used? – Virtual Private Cloud. It lets you create isolated networks in AWS with your own CIDR, subnets, route tables and security.
12. Public vs private subnet? – Public subnet has route to internet gateway; instances can be accessed from the internet. Private subnet has no direct internet route, usually used for DBs and internal services.
13. What is an Internet Gateway and NAT Gateway? – IGW gives internet access to public subnets. NAT Gateway lets private subnet instances reach the internet for updates without being reachable from outside.
14. Difference between EBS and EFS? – EBS is block storage for a single AZ and single instance (or multi‑attach for some types). EFS is shared NFS‑like file system that can attach to many instances.
15. What are AWS load balancers? – ELB service with ALB, NLB and CLB. They distribute traffic across instances or containers and support health checks.
16. What is Route 53? – Scalable DNS service that routes end users to applications using records and health checks.
17. What is S3 lifecycle policy? – Rules that automatically transition or expire objects (for example move to Glacier after 30 days).
18. What is AWS Lambda? – Serverless compute where you run code in response to events without managing servers, billed per request and execution time.
19. What is CloudFormation? – Infrastructure as Code service where you define AWS resources in templates (YAML/JSON) and deploy stacks.
20. Explain shared responsibility model. – AWS is responsible for security of the cloud (hardware, networking, facilities). Customer is responsible for security in the cloud (data, configuration, IAM, OS).

Part 3 – Scenario / Architect Questions

21. How do you build a highly available web application on AWS? – Use multi‑AZ ALB, EC2 Auto Scaling group across AZs, RDS Multi‑AZ or Aurora, S3 for static content, and Route 53 for DNS with health checks.
22. How would you secure an S3 bucket? – Block public access by default, use bucket policies + IAM roles, use encryption at rest (SSE‑S3/SSE‑KMS) and in transit (HTTPS), and enable access logging.
23. How do you back up and restore an RDS database? – Use automated backups and snapshots. Restore by creating a new DB instance from snapshot or point‑in‑time restore.
24. How do you design for sudden traffic spikes on AWS? – Place ALB in front, configure Auto Scaling policies, use CloudFront for caching, and decouple heavy processing with SQS / SNS and serverless.
25. How would you reduce AWS cost for an app? – Right‑size instances, use Savings Plans/Reserved Instances for steady workloads, use Spot for flexible jobs, enable S3 lifecycle, and clean unused resources.
26. What is a multi‑AZ vs multi‑region setup? – Multi‑AZ: high availability inside one region. Multi‑region: disaster recovery or global low‑latency; higher complexity and cost.
27. How do you implement disaster recovery on AWS? – Choose strategy (backup & restore, pilot light, warm standby, multi‑site). Use cross‑region backups, Route 53 failover, and IaC to rebuild quickly.
28. How will you integrate on‑premise data centre with AWS? – Use Site‑to‑Site VPN or Direct Connect to connect VPC with on‑prem network; use appropriate routing and security rules.
29. Explain blue/green deployment on AWS. – Run two environments (blue=current, green=new). Deploy to green, test, then switch traffic using load balancer, Route 53 or CodeDeploy, with easy rollback.
30. How do you centralise logs from multiple AWS services? – Use CloudWatch Logs agents / Fluent Bit to send logs to a central log group or to OpenSearch; create dashboards and alerts.

Part 4 – Quick‑Fire Questions (Short Answers)

31. Difference between stop and terminate EC2 instance.
32. What is EBS snapshot?
33. What is ECR?
34. What is AWS Fargate?
35. What is AWS Organizations used for?
36. What is KMS?
37. What is CloudTrail?
38. What is SQS vs SNS?
39. What is Amazon DynamoDB?
40. What is AWS WAF and where do you attach it?
41. What is Aurora and why is it used?
42. What are S3 storage classes?
43. What is ElastiCache?
44. What is AWS Config?
45. What is AWS Well‑Architected Framework?
46. What is parameter store / Secrets Manager?
47. What is Elastic Beanstalk?
48. What is Transit Gateway?
49. What is Direct Connect?
50. What is Shield and how is it different from WAF?

In interviews, give short 2–3 line answers first. If the interviewer wants more depth, then go into architecture diagrams or real examples from your project.

How to Use These Questions Effectively

Practise answering each question out loud and always connect the answer with at least one real scenario from your project or lab work on AWS.

To build those real projects, you can join our AWS Cloud and DevOps Engineering programs where the same questions are covered with hands‑on labs and mock interviews.