4.3.3. Sample Questions - Domain 3: Resilient Cloud Solutions
Question 1:
A company is running a critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB). They need to ensure high availability and automatic recovery in case an EC2 instance becomes unhealthy. Which combination of AWS services should be configured to meet this requirement, adhering to the First Principle of designing for failure?
A) Amazon S3 and AWS CloudFront B) Amazon RDS Multi-AZ and AWS Backup C) Amazon EC2 Auto Scaling and ALB health checks D) AWS Lambda and Amazon API Gateway
Correct Answer: C
Explanation:
- C) Amazon EC2 Auto Scaling and ALB health checks: This combination directly addresses the requirement. ALB health checks continuously monitor the health of registered EC2 instances. If an instance fails health checks, the ALB stops sending traffic to it. EC2 Auto Scaling, configured with health checks, can then automatically terminate the unhealthy instance and launch a new, healthy one, ensuring continuous availability and automatic recovery. This aligns with the First Principle of Automated Self-Healing and Fault Tolerance.
Question 2:
A global e-commerce application needs to provide low-latency access to its data for users worldwide and ensure business continuity even in the event of a regional disaster. The application uses Amazon DynamoDB as its primary data store. Which DynamoDB feature should be implemented to meet these requirements for global resilience?
A) DynamoDB Streams B) DynamoDB Accelerator (DAX) C) Global Tables D) On-Demand Backup and Restore
Correct Answer: C
Explanation:
- C) Global Tables: DynamoDB Global Tables provide a fully managed, multi-Region, multi-master database that enables you to run and access data in multiple AWS Regions. They automatically replicate data across your chosen Regions, providing low-latency access for global users and serving as a robust solution for disaster recovery by allowing applications to failover to another Region seamlessly. This aligns with the First Principle of Global Resilience and Active-Active Disaster Recovery.
