SOA-C03 · Question #28
A company's ecommerce application is running on Amazon EC2 instances that are behind an Application Load Balancer (ALB). The instances are in an Auto Scaling group. Customers report that the website…
The correct answer is B. Add Elastic Load Balancing (ELB) health checks to the Auto Scaling group. In this scenario, the EC2 instances pass their EC2 status checks, indicating that the operating system is responsive. However, the application hosted on the instance is failing intermittently, returning HTTP 500 errors. This demonstrates a discrepancy between the instance-level…
Question
A company's ecommerce application is running on Amazon EC2 instances that are behind an Application Load Balancer (ALB). The instances are in an Auto Scaling group. Customers report that the website is occasionally down. When the website is down, it returns an HTTP 500 (server error) status code to customer browsers. The Auto Scaling group's health check is configured for EC2 status checks, and the instances appear healthy. Which solution will resolve the problem?
Options
- AReplace the ALB with a Network Load Balancer.
- BAdd Elastic Load Balancing (ELB) health checks to the Auto Scaling group.
- CUpdate the target group configuration on the ALB. Enable session affinity (sticky sessions).
- DInstall the Amazon CloudWatch agent on all instances. Configure the agent to reboot the
How the community answered
(56 responses)- A4% (2)
- B79% (44)
- C5% (3)
- D13% (7)
Explanation
In this scenario, the EC2 instances pass their EC2 status checks, indicating that the operating system is responsive. However, the application hosted on the instance is failing intermittently, returning HTTP 500 errors. This demonstrates a discrepancy between the instance-level health and the application-level health. Auto Scaling groups should incorporate Elastic Load Balancing (ELB) health checks instead of relying solely on EC2 status checks. The ELB health check probes the application endpoint (for example, HTTP or HTTPS target group health checks), ensuring that the application itself is functioning correctly. When an instance fails an ELB health check, Amazon EC2 Auto Scaling will automatically mark the instance as unhealthy and replace it with a new one, ensuring continuous availability and performance optimization. "Implement monitoring and health checks using ALB and EC2 Auto Scaling integration. Application Load Balancer health checks allow Auto Scaling to terminate and replace instances that fail application-level health checks, ensuring consistent application performance." "When you enable the ELB health check type for your Auto Scaling group, Amazon EC2 Auto Scaling considers both EC2 status checks and Elastic Load Balancing health checks to determine instance health. If an instance fails the ELB health check, it is automatically replaced." Therefore, the correct answer is B, as it ensures proper application-level monitoring and remediation using ALB-integrated ELB health checks--a core CloudOps operational practice for proactive incident response and availability assurance.
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