CLF-C02 Cloud Concepts Practice Question
A company runs an e-commerce application on a fleet of Amazon EC2 instances. The application experiences unpredictable traffic spikes during flash sales. To handle this, the company configures an Amazon EC2 Auto Scaling group to automatically add instances when CPU utilization exceeds 70% and remove instances when utilization drops below 30%. The company only pays for the instances that are running. This ability to dynamically add and remove compute capacity based on real-time demand best demonstrates which essential characteristic of cloud computing?
⚠ Common exam trap
A common mix-up: candidates confuse elasticity with on-demand self-service, but on-demand self-service is about provisioning resources without manual intervention, whereas elasticity is specifically about scaling resources up and down to match demand.
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
✓
Elasticity
The scenario describes an Auto Scaling group that adds EC2 instances when CPU exceeds 70% and removes them when it drops below 30%, paying only for running instances. This ability to automatically scale compute capacity up and down in response to real-time demand is the defining characteristic of elasticity in cloud computing, which allows resources to be provisioned and de-provisioned dynamically to match workload fluctuations.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Elasticity
Why this is correct
Elasticity is the cloud characteristic that allows infrastructure to automatically expand and contract in response to real-time demand. An Auto Scaling group continuously monitors load metrics and adds or removes EC2 instances via scaling policies, directly demonstrating the dynamic provisioning and deprovisioning that defines elasticity. This is distinct from static scalability because it also handles demand decreases, ensuring resources match current needs and minimizing cost.
- ✗
On-demand self-service
Why it's wrong here
Incorrect. On-demand self-service means a consumer can provision resources without requiring human interaction from the provider. While Auto Scaling uses this capability, the primary characteristic demonstrated here is the dynamic scaling itself, not the self-service provisioning.
- ✗
Measured service
Why it's wrong here
Incorrect. Measured service means cloud resources are metered and usage can be monitored, controlled, and reported. While the company pays only for running instances (a result of metering), the core behavior described is the automatic scaling, not the metering.
When this WOULD be correct
A company uses a cloud provider that charges per hour of EC2 instance usage and provides detailed billing reports showing CPU utilization and network I/O. The question asks which characteristic allows the provider to charge only for actual usage, making measured service correct.
- ✗
Resource pooling
Why it's wrong here
Resource pooling refers to the provider's use of shared, multi-tenant infrastructure where physical and virtual resources are dynamically assigned to many customers. In this scenario, the Auto Scaling group operates within a single company's account, automatically adjusting its own instance count, which does not illustrate the provider-side aggregation of resources across customers. While public clouds inherently rely on resource pooling, the described behavior is an example of elasticity, not pooling.
When this WOULD be correct
A question asks: 'Which cloud characteristic allows multiple customers to share the same physical infrastructure while maintaining isolation?' Resource pooling would be the correct answer because it describes the multi-tenant model where resources are pooled and allocated on demand.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The CLF-C02 exam frequently reuses these exact scenarios with slightly different constraints.
✓ElasticityCorrect answer▾
Why this is correct
Elasticity is the cloud characteristic that allows infrastructure to automatically expand and contract in response to real-time demand. An Auto Scaling group continuously monitors load metrics and adds or removes EC2 instances via scaling policies, directly demonstrating the dynamic provisioning and deprovisioning that defines elasticity. This is distinct from static scalability because it also handles demand decreases, ensuring resources match current needs and minimizing cost.
✗Measured serviceWrong answer — click to see why▾
Why this is wrong here
Measured service refers to the metering and billing of cloud resource usage, not the dynamic scaling of resources. The question focuses on adding/removing instances based on demand, which is elasticity.
★ When this WOULD be the correct answer
A company uses a cloud provider that charges per hour of EC2 instance usage and provides detailed billing reports showing CPU utilization and network I/O. The question asks which characteristic allows the provider to charge only for actual usage, making measured service correct.
Why candidates choose this
Candidates may confuse 'measured service' with the ability to monitor and respond to metrics like CPU utilization, but measured service is about metering and billing, not automatic scaling.
✗Resource poolingWrong answer — click to see why▾
Why this is wrong here
Resource pooling refers to the provider's computing resources being pooled to serve multiple customers, with physical and virtual resources dynamically assigned according to customer demand. This question specifically highlights the ability to scale capacity up and down based on demand, which is elasticity, not resource pooling.
★ When this WOULD be the correct answer
A question asks: 'Which cloud characteristic allows multiple customers to share the same physical infrastructure while maintaining isolation?' Resource pooling would be the correct answer because it describes the multi-tenant model where resources are pooled and allocated on demand.
Why candidates choose this
Candidates might confuse resource pooling with elasticity because both involve dynamic allocation of resources, but resource pooling focuses on multi-tenancy and shared infrastructure, not automatic scaling based on demand.
Analysis generated from the official CLF-C02blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CLF-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 CLF-C02 exam.