Basic AWS Interview Questions (Freshers & 1-3 Years Experience)
1. What is AWS and what are its key features?
AWS is Amazon Web Services, a comprehensive cloud computing platform providing over 200 services for compute, storage, databases, analytics, and more. Key features include high availability through Regions and Availability Zones, scalability, security via IAM, and pay-as-you-go pricing.[1][7]
2. Explain the difference between AWS Regions and Availability Zones.
A Region is a geographic area like US East (N. Virginia) containing multiple isolated Availability Zones. Availability Zones are separate data centers within a Region for fault tolerance and high availability.[5][7]
3. What is the AWS Shared Responsibility Model?
AWS manages the security of the cloud infrastructure (hardware, software), while customers are responsible for security in the cloud (data, applications, access management).[2]
4. What is Amazon EC2?
Amazon EC2 (Elastic Compute Cloud) provides resizable virtual servers in the cloud for running applications. It offers instance types for different workloads with features like Auto Scaling and security groups.[2][3]
5. What is Amazon S3?
Amazon S3 (Simple Storage Service) is object storage for storing and retrieving data at scale. It supports durability of 99.999999999%, lifecycle policies, and storage classes like Standard and Glacier.[1]
6. What is Amazon VPC?
Amazon VPC (Virtual Private Cloud) lets you provision a logically isolated network in AWS. It includes subnets, route tables, internet gateways, and security groups for network control.[3]
7. What are Security Groups in AWS?
Security Groups act as virtual firewalls for EC2 instances, controlling inbound and outbound traffic. By default, all inbound traffic is denied, and outbound is allowed.[4]
8. What is Amazon CloudWatch?
Amazon CloudWatch monitors AWS resources and applications, collecting metrics, logs, and setting alarms. For example, it tracks CPU usage on EC2 instances.[5]
9. Differentiate between AWS Config and AWS CloudTrail.
AWS Config tracks resource configuration changes over time, while CloudTrail logs API calls and user actions across the AWS account.[5]
10. What is Elastic Load Balancing (ELB)?
ELB automatically distributes incoming traffic across multiple targets like EC2 instances for high availability and fault tolerance.[1]
Intermediate AWS Interview Questions (1-3 & 3-6 Years Experience)
11. How do you enable high availability for a web application on AWS?
Deploy EC2 instances in an Auto Scaling group across multiple Availability Zones, use Application Load Balancer to distribute traffic, and store static assets in S3 with CloudFront CDN.[3][4]
12. What is the difference between stopping and terminating an EC2 instance?
Stopping an EC2 instance releases compute capacity but preserves the EBS root volume. Terminating deletes the instance and optionally the attached volumes.[4]
13. Explain horizontal vs vertical scaling in AWS.
Horizontal scaling adds more EC2 instances behind a load balancer. Vertical scaling increases CPU/RAM on a single EC2 instance.[5]
14. How do you configure VPC Peering in AWS?
Create a peering connection request from one VPC owner, accept it from the peer VPC, then update route tables to route traffic via the peering connection. Use cases include private communication between VPCs.[3]
15. What is Amazon RDS and its benefits?
Amazon RDS is a managed relational database service supporting MySQL, PostgreSQL, etc. Benefits include automated backups, Multi-AZ deployments, and patching.[3]
16. Differentiate between Amazon S3 Standard and S3 Intelligent-Tiering.
S3 Standard is for frequently accessed data. S3 Intelligent-Tiering automatically moves data between tiers based on access patterns to optimize costs.[1]
17. What is AWS IAM and how do you secure access?
IAM manages users, groups, roles, and permissions. Secure access using least privilege principle, MFA, and IAM policies.[1]
18. Explain Auto Scaling in AWS.
Auto Scaling automatically adjusts EC2 capacity based on demand using CloudWatch metrics like CPU utilization, ensuring availability and cost efficiency.[1]
19. What is Amazon Route 53?
Route 53 is a scalable DNS web service with health checks and failover routing for high availability.[2]
20. How does CodePipeline differ from CodeDeploy?
CodePipeline orchestrates CI/CD workflows (build, test, deploy). CodeDeploy handles deployment to EC2, Lambda, or on-premises servers.[5]
Advanced AWS Interview Questions (3-6+ Years Experience)
21. Design a highly available web application architecture on AWS for Zoho.
Use Multi-AZ Auto Scaling groups with EC2, Application Load Balancer, RDS Multi-AZ database, S3 for static assets, CloudFront CDN, and Route 53 with health checks for failover.[2]
22. Explain the AWS Well-Architected Framework pillars.
The six pillars are: Operational Excellence, Security, Reliability, Performance Efficiency, Cost Optimization, and Sustainability. They guide best practices for workloads.[2]
23. How would you troubleshoot 502 errors in an Application Load Balancer at Paytm?
Check ALB access logs, target health checks, application logs, timeout settings, security groups, and CloudWatch metrics for capacity issues.[2]
24. Design a CI/CD pipeline for containerized apps at Salesforce.
Use CodePipeline with CodeCommit source, CodeBuild for building Docker images to ECR, and CodeDeploy to ECS with blue-green deployments.[2]
25. What disaster recovery plans would you implement for critical apps at SAP?
Set up S3 cross-region replication, EC2 AMIs in secondary region, RDS Multi-AZ with read replicas, CloudFormation for infrastructure, and regular DR testing.[3]
26. How do you optimize costs in AWS for Oracle workloads?
Use Reserved Instances, Spot Instances, Auto Scaling, S3 lifecycle policies, and CloudFront caching to reduce expenses.[1]
27. Differentiate AWS Direct Connect and VPN.
Direct Connect offers dedicated low-latency private connection. VPN uses public internet with potentially higher latency.[5]
28. Design a data lake architecture on AWS for Atlassian.
Store raw data in S3, use AWS Glue for ETL, IAM/Lake Formation for security, Athena for querying, and QuickSight for visualization.[1]
29. How do you implement fault tolerance in microservices at Adobe?
Use Multi-AZ deployments, Auto Scaling, load balancing, fault isolation, regular backups, and AWS Well-Architected Framework for resilience.[1]
30. Explain KMS vs CloudHSM for encryption at Swiggy.
AWS KMS is managed key service for encryption. CloudHSM provides dedicated hardware modules for full key control and compliance.[5]
