AWS Certified SysOps Administrator – Associate (legacy) — Question 69

An application is running on Amazon EC2 instances behind a Classic Load Balancer. The instances run in an Auto Scaling group across multiple Availability
Zones. Occasionally multiple incoming requests will receive a 5xx HTTP response when making a request to the Classic Load Balancer. From the Amazon
CloudWatch metrics, a SysOps Administrator observes the Elastic Load Balancing (ELB) SpillOverCount metric to be greater than zero during these occasions.
These errors can be avoided by triggering scaling actions on which ELB metric?

Answer options

• A. HealthyHostCount
• B. BackendConnectionErrors
• C. SurgeQueueLength
• D. UnHealthyHostCount

Correct answer: C

Explanation

The SurgeQueueLength metric indicates the number of requests queued for processing when the load balancer is unable to direct them to the available instances due to high traffic. When this metric is high, it suggests that scaling actions are needed to accommodate increased demand. The other metrics, while relevant, do not directly correlate with the need for scaling in response to high incoming traffic.