Examkin

Question

Difficulty: EasyAuto Scaling and Elasticity

A SysOps administrator notices that an Auto Scaling group is launching excessive, redundant EC2 instances shortly after a scale-out event begins. This behavior occurs because new instances are still bootstrapping and have not yet begun reporting metrics, causing the CloudWatch alarm to remain in the ALARM state. Which Auto Scaling configuration setting should the administrator adjust to prevent these redundant scaling actions?

  1. A
    Configure detailed monitoring on the launch template to increase the frequency of EC2 instance metrics.
  2. Increase the default instance warmup or scaling cooldown setting.Answer
  3. C
    Attach an IAM policy with the iam:PassRole permission to the Auto Scaling group's service-linked role.
  4. D
    Create an Amazon EventBridge rule that triggers an AWS Systems Manager Automation document to delete duplicate scaling requests.

Answer

Increase the default instance warmup or scaling cooldown setting.
Increasing the default instance warmup or scaling cooldown setting prevents the Auto Scaling group from launching additional instances while the existing ones are still bootstrapping. This gives the newly launched instances enough time to start reporting metrics and potentially bring the metric back to normal levels, resolving the alarm state.

Step-by-Step Solution

1
Analyze the root cause of the redundant instance launches, which is that the Auto Scaling group triggers new scale-out actions before previously launched instances are fully operational and reporting metrics.
Identify that the Auto Scaling group is acting too quickly on historical alarm data.
Understanding the timing of scaling actions is essential to resolving resource over-provisioning.
2
Identify the parameters that control the pause or grace period after a scaling action, specifically the instance warmup and scaling cooldown settings.
Recognize that increasing these parameters forces the Auto Scaling group to wait.
This allows newly launched instances enough time to finish bootstrapping and start reporting metrics to CloudWatch.
3
Select the option that recommends increasing the default instance warmup or scaling cooldown settings.
Determine the correct configuration change to prevent redundant launches.
This directly mitigates the issue without introducing unnecessary architectural complexity or permission changes.

Key Concept

Auto Scaling cooldown and warmup periods
Rate this question

Topics

Auto Scaling and Elasticity

More questions from this topic