AWS Scenario-Based Questions Answers

 

1️⃣ Scenario: Your API Suddenly Becomes Slow During Peak Traffic

Problem:
Users report high response times during sale traffic.

✅ What Should You Check?

  1. Check CPU & memory in Amazon CloudWatch

  2. Verify Auto Scaling group configuration

  3. Check database performance in Amazon RDS

  4. Look for slow queries

  5. Confirm Load Balancer health checks

✅ Production-Level Solution:

  • Enable Amazon EC2 Auto Scaling

  • Add read replicas in RDS

  • Optimize slow SQL queries

  • Use caching (Redis / ElastiCache)

  • Move static content to Amazon S3

2️⃣ Scenario: Database Server Crashes in Production

Problem:
Primary DB instance becomes unavailable.

Correct Production Setup:

Enable Multi-AZ in:
Amazon RDS

This ensures:

  • Standby replica in another AZ

  • Automatic failover

  • Minimal downtime

Wrong Answer:

“Restart the instance.”

That’s reactive, not production-ready.

3️⃣ Scenario: Your EC2 Instance Was Hacked

Problem:
Suspicious activity detected.

Immediate Actions:

  1. Detach instance from Load Balancer

  2. Rotate IAM credentials using AWS Identity and Access Management

  3. Check logs in CloudWatch

  4. Analyze Security Groups

  5. Replace instance (immutable infrastructure)

Preventive Measures:

  • Keep EC2 in private subnet

  • Use IAM Roles (not access keys)

  • Restrict SSH access

  • Enable WAF:
    AWS WAF

4️⃣ Scenario: Users Cannot Upload Files

Problem:
Media upload failing in production.

What To Check:

If using:
Amazon S3

  • Check bucket permissions

  • Verify IAM role attached to EC2

  • Confirm correct region

  • Check CORS configuration

5️⃣ Scenario: EC2 in Private Subnet Cannot Access Internet

Problem:
App cannot call third-party APIs.

Likely Cause:

Missing:
NAT Gateway

Solution:

  • Create NAT Gateway in public subnet

  • Update private subnet route table

6️⃣ Scenario: High AWS Bill at End of Month

Problem:
Unexpected cost spike.

Steps To Diagnose:

Use:
AWS Cost Explorer

Check:

  • Idle EC2 instances

  • Unattached EBS volumes

  • Over-provisioned RDS

  • Unused Load Balancers

Cost Optimization Strategy:

  • Enable Auto Scaling

  • Use Reserved Instances

  • Stop non-prod environments at night

  • Enable S3 lifecycle rules

7️⃣ Scenario: Deployment Caused Downtime

Problem:
New version deployment breaks API.

Production-Ready Approach:

  • Use Blue-Green deployment

  • Keep two environments

  • Switch traffic via Load Balancer:
    Elastic Load Balancing

  • Use CI/CD via:
    GitHub Actions

8️⃣ Scenario: Need to Handle 10x Traffic Growth

Problem:
Startup growth phase.

Architecture Upgrade:

  • Use:
    Amazon EC2 Auto Scaling

  • Add Read Replicas in RDS

  • Move session storage to Redis

  • Use CDN (CloudFront)

  • Store static/media in S3

9️⃣ Scenario: API Facing DDoS Attack

Protection Strategy:

  • Enable:
    AWS WAF

  • Use AWS Shield

  • Enable rate limiting

  • Use Load Balancer

  • Monitor via CloudWatch

🔟 Scenario: Need Zero Downtime Deployment

Correct Approach:

  • Use Load Balancer

  • Use Auto Scaling Group

  • Deploy new version to new instances

  • Health check before routing traffic

Services involved:

  • Elastic Load Balancing

  • Amazon EC2 Auto Scaling


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