SAA-C03 Practice Question 16: Route 53 Failover Routing
AWS Certified Solutions Architect – Associate (SAA-C03) · Test 2 · question 6 of 10
A travel booking site runs behind an Application Load Balancer in us-east-1. A scaled-down standby copy of the stack runs behind its own ALB in us-west-2 and should receive no user traffic while us-east-1 is working.
If the us-east-1 endpoint becomes unhealthy, DNS must send users to us-west-2 automatically, without anyone editing records. Which Amazon Route 53 configuration meets these requirements?
Show answer and explanation
Answer:
The requirement describes active-passive failover, and in Route 53 that is what the failover routing policy is for. While the primary resource is healthy, Route 53 answers queries only with the primary record. When health checking finds the primary unhealthy, Route 53 starts answering with the secondary record. For alias records that point at an ALB, you can set *Evaluate target health* so that the ALB's own health drives the decision, or attach a Route 53 health check. Either way the switch is automatic and needs no record edits.
Option B looks like active-passive but cannot fail over by itself. With no health checks, Route 53 has no signal that us-east-1 is down, so it keeps returning the weight-100 record. Someone would have to change the weights by hand, which the stem rules out.
Option C is an active-active design. Latency-based routing sends each user to the Region with the lowest latency, so West Coast users would reach the standby all the time, which breaks the "no user traffic" requirement.
Option D is also active-active. Multivalue answer routing returns up to eight healthy records in random order, spreading traffic across both Regions instead of holding one in reserve.
Reference: Active-active and active-passive failover