AWS - CloudWatch
You configured a CloudWatch alarm to trigger an Auto Scaling policy, but the instances are not scaling when the alarm state changes. What is the most likely cause?
You configured a CloudWatch alarm to trigger an Auto Scaling policy, but the instances are not scaling when the alarm state changes. What is the most likely cause?
medium📝 Debug Q14 of 15
Step-by-Step Solution
Solution:
Step 1: Check AlarmActions configuration
If the Auto Scaling policy ARN is missing or incorrect, the alarm cannot trigger scaling.Step 2: Rule out other options
SNS subscription missing affects notifications, not scaling. Threshold too low triggers alarm but no scaling if policy missing. Stopped instances do not scale but alarm triggers still need correct action.Final Answer:
The alarm's AlarmActions does not include the correct Auto Scaling policy ARN -> Option DQuick Check:
Correct Auto Scaling ARN needed in AlarmActions [OK]
Quick Trick: Auto Scaling needs correct policy ARN in AlarmActions [OK]
Common Mistakes:
- Confusing SNS subscription with scaling trigger
- Ignoring ARN correctness
- Assuming stopped instances auto scale
Master "CloudWatch" in AWS
Want More Practice?
15+ quiz questions · All difficulty levels · Free
Free Signup - Practice All QuestionsMore AWS Quizzes