Exam AWS Certified Solutions Architect - Professional SAP-C02 topic 1 question 8 discussion

I go with B https://docs.amazonaws.cn/en_us/Route53/latest/DeveloperGuide/welcome-health-checks.html

Option B is the least costly active-passive strategy

I Vote B. https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-failover-types.html Option A, C and D are wrong. The latency-based routing and endopoint weights should be used for active/active strategy. https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy-latency.html https://docs.aws.amazon.com/global-accelerator/latest/dg/about-endpoints-endpoint-weights.html

The best option to meet the requirements and reduce RTO to less than 15 minutes is to choose option B. Option B involves creating an AWS Lambda function in the backup region to promote the read replica and modify the Auto Scaling group values. Additionally, Route 53 can be configured with a health check that monitors the web application and sends an Amazon SNS notification to the Lambda function when the health check status is unhealthy. The application's Route 53 record can be updated with a failover policy that routes traffic to the ALB in the backup Region when a health check failure occurs. This option is cost-effective as it does not require an active-active strategy, and it uses AWS services to minimize the RTO. The Lambda function can be invoked to promote the read replica in the backup region, and the Auto Scaling group values can be updated to launch EC2 instances in the backup region. Furthermore, the Route 53 health check feature can be used to monitor the web application and initiate the failover process.

Option A - This option will not work as needed: The client will get errors when the closest region is the application's backup region Option B - This option implements an active-passive strategy as needed: When the health check fails, Route 53 will resolve to the backup region and the Lambda function will ensure the backup region has resources to function Option C - This option implements an active-active strategy Option D - This option will not work as needed: The client will get errors 50% of the time

B is right.

B. Create an AWS Lambda function in the backup Region to promote the read replica and modify the Auto Scaling group values. Configure Route 53 with a health check that monitors the web application and sends an Amazon Simple Notification Service (Amazon SNS) notification to the Lambda function when the health check status is unhealthy. Update the application’s Route 53 record with a failover policy that routes traffic to the ALB in the backup Region when a health check failure occurs.

Correct answer B

B for sure

This explains Lambda promoting backup read replica in other region - https://medium.com/ankercloud-engineering/aws-lambda-promoting-rds-read-replica-on-cross-region-using-aws-lambda-113db758869

why we need Lambda Function ? Is it enough a Route 53 failover policy ?

The problem is not detecting the right answer, but reading quickly enough trough all the words in the question!

B satisfies all the requirements.

Health check is a metric, hence alarms can be executed, and alarms are integrated with SNS, SNS integrated with lambda. This sounds weird, but it will work.

B. Create an AWS Lambda function in the backup Region to promote the read replica and modify the Auto Scaling group values. Configure Route 53 with a health check that monitors the web application and sends an Amazon Simple Notification Service (Amazon SNS) notification to the Lambda function when the health check status is unhealthy. Update the application’s Route 53 record with a failover policy that routes traffic to the ALB in the backup Region when a health check failure occurs.

Health check+SNS. This does not need to have active-active which satisfy the rquirement.

it's a B again