DOP-C02 Question 138
Select 3Your organization has a business-critical web application hosted on Amazon EC2 instances behind an Application Load Balancer (ALB). The application must maintain high availability and resilience against failures in a single AWS Region. Business requirements dictate that downtime must be minimal and the infrastructure should automatically adapt to failure scenarios. Which solution ensures the application meets these requirements?
- A
Deploy the EC2 instances in an Auto Scaling group spanning multiple Availability Zones.
- B
Configure the ALB to route traffic only to healthy instances using health checks.
- C
Use Amazon Route 53 with latency-based routing to direct traffic to the ALB.
- D
Deploy an additional ALB in a different AWS Region for redundancy.
- E
Enable connection draining (deregistration delay) on the ALB to prevent disruption during instance removal.
Show answer and explanation
Correct answers: A, B, E
Explanation
To implement a highly available solution within a single AWS Region, it is critical to distribute EC2 instances across multiple Availability Zones using an Auto Scaling group. This setup ensures resilience against failures in a single zone. Configuring the ALB to route traffic only to healthy instances improves reliability by preventing unhealthy instances from serving requests. Additionally, enabling connection draining on the ALB ensures smooth handling of traffic during instance removal or failure. While Route 53 and cross-region ALBs are useful for global or disaster recovery scenarios, they are not necessary to meet the specific high availability requirement within a single Region.
- A. Correct.
Correct. Deploying EC2 instances in an Auto Scaling group across multiple Availability Zones ensures that the application can handle failures in a single Availability Zone, providing high availability.
- B. Correct.
Correct. Configuring the ALB to route traffic only to healthy instances ensures that unhealthy instances do not serve traffic, enhancing reliability and resilience.
- C. Incorrect.
Incorrect. While Route 53 with latency-based routing is useful for global traffic management, it is not required to maintain high availability within a single AWS Region.
- D. Incorrect.
Incorrect. Deploying an ALB in another Region is a valid strategy for disaster recovery but is not necessary for meeting high availability and resilience requirements within the same Region.
- E. Correct.
Correct. Enabling connection draining on the ALB ensures in-flight requests are completed before an instance is removed, reducing the likelihood of disruption.