Use Target Tracking Scaling Policy for Sudden Traffic Spikes
A company runs a web application on EC2 instances in an Auto Scaling group behind an Application Load Balancer. The application experiences sudden traffic spikes. What is the most effective way to ensure the application can handle the spikes without manual intervention?
Quick Answer
The answer is to use a target tracking scaling policy based on average CPU utilization. This is the most effective approach because a target tracking policy acts as a control system, automatically adjusting the Auto Scaling group’s desired capacity to maintain a predefined metric target—such as 50% CPU—even during sudden traffic spikes, without any manual intervention. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this concept tests your ability to distinguish between reactive and predictive scaling mechanisms; a common trap is choosing scheduled scaling, which only works for known, predictable patterns, not the sudden, unplanned spikes described here. Remember that target tracking is ideal for dynamic, real-time demand, while step scaling offers more granular control but requires manual threshold configuration. Memory tip: think of target tracking as a thermostat—it constantly measures the temperature (CPU) and adjusts the AC (instances) to keep the room comfortable, no matter how quickly the weather changes outside.
⚠ Common exam trap
It's easy for candidates to confuse scheduled scaling (which works only for predictable patterns) with dynamic scaling (which reacts to real-time metrics), leading them to choose D instead of A for handling sudden, unplanned traffic spikes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use a target tracking scaling policy based on average CPU utilization.
A target tracking scaling policy based on average CPU utilization is the most effective approach because it automatically adjusts the Auto Scaling group's desired capacity in real-time to maintain a target CPU metric (e.g., 50%). This dynamic scaling method responds directly to sudden traffic spikes without any manual intervention, ensuring the application can handle increased load while optimizing cost.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use a target tracking scaling policy based on average CPU utilization.
Why this is correct
Target tracking automatically adjusts capacity to maintain a target metric, handling spikes.
- ✗
Increase the instance size to handle more load per instance.
Why it's wrong here
Larger instances may still be overwhelmed; horizontal scaling is more effective.
- ✗
Manually increase the desired capacity when traffic spikes.
Why it's wrong here
Manual intervention is not automated and may not react quickly enough.
- ✗
Use scheduled scaling to add instances at expected peak times.
Why it's wrong here
Scheduled scaling is for predictable patterns, not sudden spikes.
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Variation 1. A company is deploying a web application on AWS that must scale automatically based on CPU utilization. The application runs on Amazon EC2 instances in an Auto Scaling group. Which configuration is required for the Auto Scaling group to scale based on CPU?
easy- A.Create a scheduled scaling action to add instances at peak times.
- B.Create a simple scaling policy that adds one instance when CPU exceeds 50%.
- ✓ C.Create a step scaling policy based on a CloudWatch alarm for CPU utilization.
- D.Configure the ALB health check to mark instances unhealthy if CPU is high.
Why C: A step scaling policy allows the Auto Scaling group to adjust capacity in increments based on the severity of a CloudWatch alarm, such as one monitoring CPU utilization. This provides more granular and responsive scaling than simple policies, as it can add or remove instances in steps (e.g., add 2 instances when CPU > 70%, add 1 when CPU > 50%) and supports cooldown and warm-up logic to avoid thrashing.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAP-C02 exam.