SAP-C02 · Question #173
A large company has a business-critical application that runs in a single AWS Region. The application consists of multiple Amazon EC2 instances and an Amazon RDS Multi-AZ DB instance. The EC2 instance
The correct answer is D. Publish an application availability metric to Amazon CloudWatch in the DR Region from the. To automate failover for a pilot light DR environment, application availability in the primary region should trigger actions in the DR region.
Question
A large company has a business-critical application that runs in a single AWS Region. The application consists of multiple Amazon EC2 instances and an Amazon RDS Multi-AZ DB instance. The EC2 instances run in an Amazon EC2 Auto Scaling group across multiple Availability Zones. A solutions architect is implementing a disaster recovery (DR) plan for the application. The solutions architect has created a pilot light application deployment in a new Region, which is referred to as the DR Region. The DR environment has an Auto Scaling group with a single EC2 instance and a read replica of the RDS DB instance. The solutions architect must automate a failover from the primary application environment to the pilot light environment in the DR Region. Which solution meets these requirements with the MOST operational efficiency?
Options
- APublish an application availability metric to Amazon CloudWatch in the DR Region from the
- BCreate a cron task that runs every 5 minutes by using one of the application's EC2 instances in
- CCreate a cron task that runs every 5 minutes by using one of the application's EC2 instances in
- DPublish an application availability metric to Amazon CloudWatch in the DR Region from the
How the community answered
(44 responses)- A5% (2)
- B9% (4)
- C2% (1)
- D84% (37)
Why each option
To automate failover for a pilot light DR environment, application availability in the primary region should trigger actions in the DR region.
This option is identical to D, indicating a potential issue with the question's choices, but D is designated as the correct answer in this context.
Creating a cron task on an application EC2 instance in the primary region for monitoring and failover is not a robust or highly available solution, as the monitoring instance itself could fail.
Similar to B, a cron task on a single EC2 instance is an unreliable mechanism for automating business-critical DR failover because the instance could become unavailable.
Publishing an application availability metric to Amazon CloudWatch in the primary region (implied by typical DR patterns, even though the text mentions 'DR Region') and creating an alarm can trigger automated actions, such as a Lambda function, which can promote the RDS read replica and scale out the Auto Scaling group in the DR region for failover.
Concept tested: Automated disaster recovery failover using CloudWatch alarms
Source: https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/UsingAlarmActions.html
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