SAA-C03 Design Resilient Architectures Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Keep latency-based routing, and set the weights so the secondary Region rarely receives traffic unless manual changes are made.

  Why it's wrong here

  Latency-based routing selects the Region with the lowest network latency for each user, while weighted routing merely distributes traffic according to fixed percentages. Neither policy reacts to health checks or automatically shifts traffic when the primary Region fails; the weights would remain unchanged, so the secondary Region would only receive its small configured share until someone manually adjusts the weights or the primary record is removed. This approach requires operational intervention and does not provide the deterministic, health-check-driven failover the company needs.

• ✓

  Use a Route 53 failover routing policy: configure two alias records for the ALBs where the primary record is marked PRIMARY, the secondary is marked SECONDARY, and each record has an associated health check.

  Why this is correct

  Route 53 failover routing is designed specifically for active-passive failover: you create two alias records pointing to the two ALBs, one marked PRIMARY and the other SECONDARY, each with an associated health check. Under normal conditions, Route 53 returns the PRIMARY record, but if that record's health check fails, Route 53 automatically stops returning it and returns the SECONDARY record instead. This gives the company an automated, DNS-level failover that does not depend on client latency, manual weight changes, or client-side load balancing.

• ✗

  Use an alias A record that returns both ALBs simultaneously so clients automatically load balance across Regions during outages.

  Why it's wrong here

  An alias A record in Route 53 can point to a single ALB, so returning both ALBs simultaneously would require multiple A records under the same name. Even if both are returned, DNS does not force clients to load balance; each client randomly picks one of the returned IPs, and a client may continue using the unhealthy primary Region. Health checks without a failover routing policy do not remove the unhealthy ALB from the response set, so this approach cannot guarantee that traffic shifts to the secondary only after primary failure.

• ✗

  Use geolocation routing to route users to the primary Region and rely on ALB health checks to shift requests between Regions.

  Why it's wrong here

  Geolocation routing directs users to the Region you map based on their geographic location, not on the health or availability of the ALBs. The ALB's own health checks only control whether individual targets behind that ALB are considered healthy; they have no effect on Route 53's geolocation mapping. Thus, users in the primary Region would still be routed to the primary ALB even if it is completely unhealthy, and there is no mechanism to shift requests to the secondary Region automatically.

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