How should the company complete the configuration to meet its requirements while providing the lowest latency for the application end-users?
(Choose two.)
Use failover routing and configure the us-east-1 record set as primary and the eu-west-1 record set as secondary. Configure an HTTP health check for the web application in us-east-1, and associate it to the us-east-1 record set.
Use weighted routing and configure each record set with a weight of 50. Configure an HTTP health check for each region, and attach it to the record set for that region.
Use latency-based routing for both record sets. Configure a health check for each region and attach it to the record set for that region.
Configure an Amazon CloudWatch alarm for the health checks in us-east-1, and have it invoke an AWS Lambda function that promotes the read replica in eu- west-1.
Configure Amazon RDS event notifications to react to the failure of the database in us-east-1 by invoking an AWS Lambda function that promotes the read replica in eu-west-1.
Explanations:
Failover routing is not suitable as it would only direct traffic to the secondary region after the primary region has been marked as unhealthy. Since the application can be in read-only mode for up to 1 hour, this may not ensure a seamless user experience during a region failure, as it could lead to downtime until failover is complete.
Weighted routing could distribute traffic but does not inherently provide failover capabilities. If us-east-1 becomes unavailable, traffic would continue to be sent to that region until a health check fails, which may not meet the requirement of maintaining availability.
Latency-based routing will direct users to the region with the lowest latency, enhancing performance. Additionally, health checks will ensure that if one region goes down, traffic will automatically route to the other region, maintaining availability even during a failure.
While promoting the read replica can help in failover scenarios, this option does not directly address how users are routed to the available region during a failure. It adds a layer of complexity and doesn’t ensure immediate routing to the eu-west-1 region for end-users.
Configuring RDS event notifications to promote the read replica provides a proactive approach to database failover. This ensures that in case of a failure in the primary region, the read replica is promoted automatically, minimizing downtime and maintaining data availability, though the application would still be in read-only mode.
I structure that the answer is:
Use latency-based routing for both record sets. Configure a health check for each region and attach it to the record set for that region.