Exam AWS Certified SysOps Administrator - Associate topic 1 question 182 discussion

I have to vote "B" because if you continue to read the whole quote, AWS recommends step scaling over target tracking in this instance, e.g.: "We strongly recommend that you use a target tracking scaling policy to scale on a metric like average CPU utilization or the RequestCountPerTarget metric from the Application Load Balancer. Metrics that decrease when capacity increases and increase when capacity decreases can be used to proportionally scale out or in the number of instances using target tracking. This helps ensure that Amazon EC2 Auto Scaling follows the demand curve for your applications closely." ... "You still have the option to use step scaling as an additional policy for a more advanced configuration. For example, you can configure a more aggressive response when demand reaches a certain level." https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-scaling-simple-step.html

C AWS recommend use "target tracking scaling". "We strongly recommend that you use a target tracking scaling policy to scale on a metric like average CPU utilization or the RequestCountPerTarget metric from the Application Load Balancer. " https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-scaling-simple-step.html

B is the correct choice: B. Create a step scaling policy with settings to make larger adjustments in capacity when the system is under heavy load: ------ Step scaling policies allow you to configure different scaling adjustments for different breach levels. In this case, you can set larger adjustments for larger increases in traffic. This helps the Auto Scaling group add more capacity quickly during periods of rapid traffic increases.

B is the correct one!

B, the question says "During periods of rapid traffic increases" meaning more than one increase. "In contrast, with step scaling the policy can continue to respond to additional alarms, even while a scaling activity or health check replacement is in progress. Therefore, all alarms that are breached are evaluated by Amazon EC2 Auto Scaling as it receives the alarm messages." https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-scaling-simple-step.html#as-step-scaling-warmup

"The main difference between the policy types is the step adjustments that you get with step scaling policies. When step adjustments are applied, and they increase or decrease the current capacity of your Auto Scaling group, the adjustments vary based on the size of the alarm breach." -- C

B for me, "You still have the option to use step scaling as an additional policy for a more advanced configuration. For example, you can configure a more aggressive response when demand reaches a certain level."

C for me, https://docs.aws.amazon.com/autoscaling/application/userguide/application-auto-scaling-tutorial.html

why not C: Target Scaling must wait for additional alarms (cause delay) why B: Step Scaling handle multiple alrams.

The correct answer is B. Create a step scaling policy with settings to make larger adjustments in capacity when the system is under heavy load. Step scaling policies are suitable for scenarios where you want to add more capacity to the Auto Scaling group as the traffic increases. With step scaling policies, you can define specific thresholds for different levels of traffic and configure the scaling adjustments accordingly. This allows you to add more capacity during larger traffic increases while minimizing costs during smaller traffic increases. Option A (Create a simple scaling policy) might not be the best choice as it does not provide the granularity needed to handle larger traffic increases differently from smaller ones.

C is answer

BBB is the right answer and not C In contrast, with step scaling the policy can continue to respond to additional alarms, even while a scaling activity or health check replacement is in progress. Therefore, all alarms that are breached are evaluated by Amazon EC2 Auto Scaling as it receives the alarm messages. https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-scaling-simple-step.html#SimpleScaling

When step adjustments are applied, and they increase or decrease the current capacity of your Auto Scaling group, the adjustments vary based on the size of the alarm breach. https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-scaling-simple-step.html

With a target tracking scaling policy, the SysOps administrator can define a target value for a specific metric that the Auto Scaling group will try to maintain. When the metric exceeds the target value, the policy will automatically add more instances to the Auto Scaling group. By configuring the scaling policy to make larger adjustments in capacity when the system is under heavy load, the Auto Scaling group will add more capacity for larger traffic increases. This will help to improve the user experience during periods of rapid traffic increases, without incurring unnecessary costs during normal traffic periods.

Answer is "B" - you need to identify a specific metric to use "C" and there's no indication that is a "known quantity." Both answers are very close, but I have to go with "B" for this reason.

Looks like B

https://docs.aws.amazon.com/autoscaling/ec2/userguide/as-scaling-simple-step.html