Exam AWS Certified SysOps Administrator - Associate topic 1 question 325 discussion

"all target instances" means zero Healthy, not one Healthy. "<= 0" means less than or equal to zero

The question states: The administrator wants to set an alarm for when all target instances associated with the ALB are unhealthy. A. AWS/ApplicationELB HealthyHostCount <= 0 would trigger the Alarm because all the host are unhealthy. Option B: would trigger if one or more is unhealthy but you would still could have healthy host!

A is not correct: This would trigger an alarm only if none of the target instances are healthy, but it may not capture cases where some instances are unhealthy.

Option B, "AWS/ApplicationELB UnhealthyHostCount >= 1," is the correct condition for triggering an alarm when at least one target instance associated with the ALB is unhealthy. This condition ensures that the alarm is triggered when the count of unhealthy instances is greater than or equal to 1. -- Options A and C are incorrect because they are checking for healthy instances: Option A, "AWS/ApplicationELB HealthyHostCount <= 0," would trigger the alarm when the count of healthy instances is zero or less, which is the opposite of the requirement.

healthy <= 0 means all are unhealthy

Some of these answers really show how badly people fail at reading comprehension or are waaay to reliant on Chat AI as their justifications for their answers completely contradict what the question asks for...

B is correct The "UnhealthyHostCount" metric of the Application Load Balancer (ALB) represents the number of registered instances that are reported as unhealthy. By setting the alarm condition to "UnhealthyHostCount >= 1," the alarm will be triggered when at least one target instance associated with the ALB is reported as unhealthy.

To set an alarm for when all target instances associated with the ALB are unhealthy, the SysOps administrator should use the HealthyHostCount metric of the AWS/ApplicationELB namespace and set the condition to <= 0. This means that when the number of healthy hosts is less than or equal to 0, the alarm will be triggered 1. So, the correct answer would be A. AWS/ApplicationELB HealthyHostCount <= 0.

Option A will trigger the alarm when there are no healthy target instances. Option B will trigger the alarm when there is at least one unhealthy target instance registered with the ALB.

B. AWS/ApplicationELB UnhealthyHostCount >= 1 By using this condition, the alarm will be triggered when there is at least one unhealthy target instance associated with the Application Load Balancer (ALB).