Model answers for 4 AWS scenario questions
Typical round: scenario design, security, cost, incident
Q: Design a highly available web app on AWS. A: Spread across at least two Availability Zones: an Application Load Balancer in public subnets, an Auto Scaling group or ECS service in private subnets, RDS Multi-AZ for the database, static assets on S3 behind CloudFront, and health checks plus CloudWatch alarms.
Q: An S3 bucket was accidentally made public. What do you do? A: Turn on Block Public Access at bucket and account level, review the bucket policy and ACLs, check CloudTrail and access logs for what was read, rotate any exposed secrets, and add an AWS Config rule or SCP to prevent it happening again.
Q: How did you reduce AWS cost? A: Rightsized over-provisioned instances using Compute Optimizer, moved steady workloads to Savings Plans, added S3 lifecycle rules to Glacier, and scheduled non-production environments to stop at night. Name the percentage you saved.
Q: Lambda or containers? A: Lambda for event-driven, spiky or short tasks with low ops overhead. Containers on ECS or EKS for long-running services, steady high traffic, or when you need more control over runtime and networking.