Which combination of scaling policies should you use?
hard📝 Application Q15 of 15
AWS - Auto Scaling
You want to keep your application's CPU usage at 50% using AWS Auto Scaling. You also want to add 2 instances if CPU usage goes above 70%, and remove 1 instance if it drops below 30%. Which combination of scaling policies should you use?
AUse a target tracking policy for 50% CPU and step scaling for adding/removing instances at 70% and 30%
BUse only a simple scaling policy with fixed adjustments
CUse only a target tracking policy with target 50%
DUse scheduled scaling to add and remove instances at fixed times
Step-by-Step Solution
Solution:
Step 1: Understand target tracking role
Target tracking keeps CPU near 50% automatically adjusting capacity.
Step 2: Understand step scaling role
Step scaling defines specific actions when CPU crosses 70% (add 2) or 30% (remove 1).
Step 3: Combine policies
Use target tracking for steady state and step scaling for aggressive changes beyond thresholds.
Final Answer:
Use a target tracking policy for 50% CPU and step scaling for adding/removing instances at 70% and 30% -> Option A
Quick Check:
Target tracking + step scaling = precise control [OK]
Quick Trick:Combine target tracking for steady and step scaling for thresholds [OK]
Common Mistakes:
MISTAKES
Using only one policy type for all needs
Confusing scheduled scaling with metric-based scaling
Ignoring removal scaling actions
Master "Auto Scaling" in AWS
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