Q76 — AWS SAA-C03 Ch.16

Question 76 of 100 | ← Chapter 16

Q1276. A solutions architect is designing a multi-Region disaster recovery(DR) strategy for a company. The company runs an application on Amazon EC2 instances in Auto Scaling groups that are behind an Application Load Balancer(ALB). The company hosts the application in the company's primary and secondary AWS Regions.The application must respond to DNS queries from the secondary Region if the application in the primary Region fails. Only one Region must serve traffic at a time.Which solution will meet these requirements?

• A. Create an outbound endpoint in Amazon Route 53 Resolver. Create forwarding rules that determine how queries will be forwarded to DNS resolvers on the network. Associate the rules with VPCs in each Region.
• B. Create primary and secondary DNS records in Amazon Route 53. Configure health checks and a failover routing policy. ✓
• C. Create a traffic policy in Amazon Route 53. Use a geolocation routing policy and a value type of ELB Application Load Balancer.
• D. Create an Amazon Route 53 profile. Associate DNS resources to the profile. Associate the profile with VPCs in each Region.

Correct Answer: B. Create primary and secondary DNS records in Amazon Route 53. Configure health checks and a failover routing policy.

Explanation

The correct solution must ensure DNS failover between Regions, directing traffic to the secondary Region only if the primary fails, while using Amazon Route 53 effectively. Let's evaluate each option:Correct Answer: B. Create primary and secondary DNS records in Amazon Route 53. Configure health checks and a failover routing policy.Why Option B is Best:Active-Passive Failover:Route 53 failover routing allows defining primary (active) and secondary (standby) records. Traffic is routed to the primary ALB unless its health check fails, in which case Route 53 automatically switches to the secondary ALB.Health Checks for Reliability:Route 53 continuously monitors the primary endpoint (e.g., via HTTP/HTTPS checks). If the primary becomes unhealthy, Route 53 fails over to the secondary within seconds (configurable TTL).Single-Region Traffic at a Time:Only one record is active (primary or secondary), ensuring no split-brain scenario.Example Configuration:Primary Record:Type: A or CNAME (pointing to primary ALB DNS name).Routing Policy: Failover (PRIMARY).Health Check: Associated with primary ALB endpoint.Secondary Record:Type: A or CNAME (pointing to secondary ALB DNS name).Routing Policy: Failover (SECONDARY).Why Other Options Fail:A. Create an outbound endpoint in Amazon Route 53 Resolver. Create forwarding rules that determine how queries will be forwarded to DNS resolvers on the network. Associate the rules with VPCs in each Region.Incorrect Use Case:Route 53 Resolver is for hybrid cloud DNS resolution (on-premises AWS), not for application failover.Does not provide health checks or automatic failover.C. Create a traffic policy in Amazon Route 53. Use a geolocation routing policy and a value type of ELB Application Load Balancer.Wrong Routing Policy:Geolocation routing directs traffic based on user location, not application health. Fails to meet the requirement of failing over on health checks. D. Create an Amazon Route 53 profile. Associate DNS resources to the profile. Associate the profile with VPCs in each Region.Non-Existent Feature:Route 53 does not have "profiles" for DNS failover.This option is invalid (likely a distractor).Key Comparison:RequirementFailover Routing (B)Other OptionsAutomatic failover on health check failure (Resolver = no health checks; Geolocation = no failover) Single active Region at a time (Geolocation may route to both Regions) AWS-native solution (Resolver = hybrid; Geolocation = wrong use case)Conclusion:Option B is the only solution that:Provides health-based failover between Regions.Ensures only one Region serves traffic at a time.Uses Route 53's native failover routing (most reliable and simplest).Final Answer: B