AWS remains one of the most requested cloud skills in job postings, and AWS interviews mix conceptual questions with real-world scenarios. Whether you are interviewing for a cloud engineer, DevOps or solutions architect role, these AWS interview questions cover what interviewers ask most often.
Core AWS concepts
What are Regions and Availability Zones?
A Region is a geographic area containing multiple isolated Availability Zones (AZs). Deploying across multiple AZs improves availability.
What is the shared responsibility model?
AWS secures the cloud infrastructure; customers secure what they put in the cloud — data, identities, configurations and applications.
What is the difference between EC2, Lambda and containers?
EC2 provides virtual servers you manage. Lambda runs code on demand without servers. Containers on ECS or EKS package applications consistently and scale efficiently.
Storage and databases
What are the S3 storage classes?
S3 Standard for frequent access, Intelligent-Tiering for changing patterns, Standard-IA and One Zone-IA for infrequent access, and Glacier classes for archival.
RDS vs. DynamoDB?
RDS is a managed relational database for SQL, joins and transactions. DynamoDB is a managed NoSQL key-value and document store for high scale and low latency.
What is the difference between EBS, EFS and S3?
EBS is block storage attached to a single EC2 instance (in most cases). EFS is a shared file system. S3 is object storage accessed over APIs.
Networking
What is a VPC?
A logically isolated virtual network where you define subnets, route tables, gateways and security controls.
Public vs. private subnet?
A public subnet routes to an internet gateway. A private subnet does not; outbound internet access typically goes through a NAT gateway.
Security groups vs. network ACLs?
Security groups are stateful and apply to instances or network interfaces. Network ACLs are stateless and apply to subnets.
How do you connect multiple VPCs and on-premises networks?
VPC peering for simple connections, Transit Gateway for hub-and-spoke at scale, and Site-to-Site VPN or Direct Connect for on-premises connectivity.
Security and IAM
What are IAM users, groups, roles and policies?
Users represent people or applications, groups organize users, roles provide temporary credentials assumed by services or identities, and policies define permissions.
How do you secure an AWS account?
Enable MFA, avoid using the root user, apply least privilege, use roles instead of long-term keys, enable CloudTrail and GuardDuty, encrypt data with KMS and use AWS Organizations with service control policies for multi-account governance.
High availability and scalability
How do you design a highly available web application?
Use multiple AZs, an Application Load Balancer, Auto Scaling groups or containers, a Multi-AZ database, caching with ElastiCache or CloudFront, and health checks with automatic recovery.
What disaster recovery strategies exist?
Backup and restore, pilot light, warm standby and multi-site active/active — trading cost against recovery time and data loss.
Scenario questions
- An EC2 instance can’t reach the internet — how do you troubleshoot? (Check route tables, internet/NAT gateway, security groups, NACLs and public IP.)
- Your AWS bill doubled — what do you do? (Use Cost Explorer, tags, rightsizing, Savings Plans, and look for idle resources.)
- How would you migrate an on-premises application to AWS?
- How would you manage 100+ AWS accounts securely? (AWS Organizations, Control Tower/landing zones, SCPs, centralized logging and Infrastructure as Code.)
- How would you deploy infrastructure consistently across environments? (Terraform or CloudFormation with CI/CD.)
How to prepare
Back up your answers with real examples from projects or labs. Certifications like AWS Solutions Architect – Associate cover much of this material. Pair this guide with our system design interview framework and DevOps interview questions.
Frequently asked questions
What AWS services should I know for interviews?
EC2, S3, VPC, IAM, RDS, DynamoDB, Lambda, ELB, Auto Scaling, CloudWatch, CloudFormation and Route 53 are the most commonly discussed.
Do I need an AWS certification to pass an AWS interview?
No, but certifications help structure your knowledge and can get you past resume screens. Hands-on experience matters most.
How do I answer AWS scenario questions?
Clarify requirements, propose a design using well-known services, explain trade-offs, and address security, availability and cost.
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