SAP-C02 Continuous Improvement for Existing Solutions Practice Question
A company runs a stateless web application on EC2 instances in an Auto Scaling group. The application is deployed across multiple Availability Zones. The team notices that during a recent traffic spike, some instances were terminated and replaced, causing a temporary drop in performance. How can the team improve the resilience of the application?
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
✓
Configure a warm pool for the Auto Scaling group.
A warm pool pre-initializes instances, reducing the time needed for new instances to become ready during scale-out events. Option A is wrong because Reserved Instances guarantee capacity but do not reduce the initialization delay. Option B is wrong because lifecycle hooks can delay termination but do not accelerate instance readiness. Option C is wrong because larger instance size does not prevent the temporary drop in performance caused by instance replacement delays.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Purchase Reserved Instances to ensure capacity.
Why it's wrong here
Reserved Instances are a billing discount applied to on-demand usage; they reserve no physical capacity and do not prevent instances being terminated during scale-in or replacement. They are tempting for cost predictability on steady-state workloads, but this scenario needs a scaling policy that adds capacity before demand spikes, such as target tracking.
- ✗
Use lifecycle hooks to wait for instance termination.
Why it's wrong here
Lifecycle hooks pause an instance in a wait state during launch or termination, but they do not delay or prevent the termination itself, so capacity still drops. They are tempting for running cleanup scripts before an instance dies, yet resilience here requires scaling out earlier via a target tracking policy.
- ✗
Increase the instance size to handle more traffic.
Why it's wrong here
A larger instance size raises the ceiling for a single instance but does not change how many instances the Auto Scaling group launches, so replacements still cause a capacity dip. It is tempting because vertical scaling is simple, but the correct fix is horizontal: a target tracking policy that provisions capacity ahead of the spike.
- ✓
Configure a warm pool for the Auto Scaling group.
Why this is correct
A warm pool maintains pre-initialised instances in a stopped or running state, ready to enter service immediately. This directly addresses the performance drop caused by cold-start bootstrapping during scale-out, since replacement instances bypass lengthy application initialisation. It satisfies the resilience constraint by reducing the time the Auto Scaling group operates below desired capacity during traffic spikes.
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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.