CLF-C02 Cloud Concepts Practice Question
A company runs a critical database on a single Amazon EC2 instance in a single Availability Zone. To increase fault tolerance and minimize downtime, the architecture team decides to deploy the database across multiple Availability Zones using a primary/standby configuration. This design pattern of distributing resources across isolated locations to ensure continuous operation even if an entire data center fails best demonstrates which fundamental concept of cloud computing?
⚠ Common exam trap
AWS often tests the distinction between high availability (fault tolerance across AZs) and scalability (handling increased load), so the trap here is confusing the ability to survive failures with the ability to grow capacity.
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
✓
High availability
Deploying a critical database across multiple Availability Zones in a primary/standby configuration ensures that if one data center (AZ) fails, the standby instance can take over with minimal downtime. This design directly implements high availability (HA), which is the ability of a system to remain operational despite component failures. The scenario specifically describes fault tolerance through geographic redundancy, which is the core of HA in cloud computing.
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 it's wrong here
Elasticity is the ability to automatically add or remove compute resources to match changing demand, such as through Amazon EC2 Auto Scaling based on CPU or memory utilization. The database scenario is not about fluctuating workload or running out of capacity—it is about surviving a single point of failure where one instance crash or Availability Zone outage takes the database offline. Even a highly elastic fleet cannot maintain availability if the only database instance fails, because elasticity does not create redundancy, replicas, or automatic failover. Therefore, the correct architectural pattern is high availability, not elasticity.
When this WOULD be correct
A question describing a workload that automatically adds or removes EC2 instances in response to traffic spikes, such as an e-commerce site during a flash sale, would make elasticity the correct answer.
- ✓
High availability
Why this is correct
Correct. Deploying resources across multiple Availability Zones to withstand the failure of an entire data center is the definition of high availability in cloud computing. It ensures that the application remains accessible despite infrastructure failures.
- ✗
Scalability
Why it's wrong here
Scalability is the capacity of a system to handle increased workload by expanding resources, either by scaling up to larger instance types or scaling out with more instances to distribute the load. A single EC2 instance can be scaled vertically to a larger instance type, but that still leaves the database as a single point of failure—if that one instance or its Availability Zone becomes unavailable, the database is unreachable regardless of how powerful the instance is. The business concern in this question is continuous operation during component failure, not accommodating increasing numbers of users or transactions. Consequently, scalability addresses performance growth and demand spikes, whereas high availability addresses fault tolerance and uptime.
When this WOULD be correct
A question that asks: 'A company's e-commerce application experiences sudden spikes in traffic during flash sales. The architecture team wants to automatically add EC2 instances during peak times and remove them when demand drops. Which cloud computing concept does this best demonstrate?' Here, scalability would be correct because it focuses on adjusting capacity to meet demand.
- ✗
Security
Why it's wrong here
Security in AWS refers to protecting the confidentiality, integrity, and availability of data through controls such as IAM policies, encryption, security groups, and network access control lists. The scenario of a single EC2 instance running a critical database may certainly raise security concerns, but the question asks about resilience to infrastructure failure, not about defending against malicious activity. Deploying a second instance in another Availability Zone to achieve high availability does not, by itself, prevent unauthorized access, data leaks, or misconfigurations. Thus, security is not the concept that describes surviving an entire data-center failure, even though security and availability are both pillars of the AWS Well-Architected Framework.
When this WOULD be correct
A question asking which cloud computing concept is demonstrated by encrypting data at rest and in transit, implementing IAM policies, and configuring network ACLs to protect a multi-tier application.
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.
✓High availabilityCorrect answer▾
Why this is correct
Correct. Deploying resources across multiple Availability Zones to withstand the failure of an entire data center is the definition of high availability in cloud computing. It ensures that the application remains accessible despite infrastructure failures.
✗ElasticityWrong answer — click to see why▾
Why this is wrong here
Elasticity refers to the ability to automatically scale resources up or down based on demand, not to distributing resources across isolated locations for fault tolerance.
★ When this WOULD be the correct answer
A question describing a workload that automatically adds or removes EC2 instances in response to traffic spikes, such as an e-commerce site during a flash sale, would make elasticity the correct answer.
Why candidates choose this
Candidates may confuse the concept of adding more resources (scaling) with distributing resources for redundancy, or they might think that deploying across multiple AZs involves 'elastic' resource allocation.
✗ScalabilityWrong answer — click to see why▾
Why this is wrong here
Scalability refers to the ability to increase or decrease resources to handle varying load, not to distributing resources across isolated locations for fault tolerance. The question describes a primary/standby configuration across Availability Zones to ensure continuous operation during a data center failure, which is a high availability pattern, not scalability.
★ When this WOULD be the correct answer
A question that asks: 'A company's e-commerce application experiences sudden spikes in traffic during flash sales. The architecture team wants to automatically add EC2 instances during peak times and remove them when demand drops. Which cloud computing concept does this best demonstrate?' Here, scalability would be correct because it focuses on adjusting capacity to meet demand.
Why candidates choose this
Candidates may confuse scalability with high availability because both involve multiple resources, but scalability is about handling load changes, not ensuring uptime during failures. The term 'distributing resources' can mistakenly be associated with scaling out.
✗SecurityWrong answer — click to see why▾
Why this is wrong here
The question describes distributing resources across multiple Availability Zones to ensure continuous operation, which is a high availability pattern. Security is about protecting data and systems from threats, not about fault tolerance or minimizing downtime from infrastructure failures.
★ When this WOULD be the correct answer
A question asking which cloud computing concept is demonstrated by encrypting data at rest and in transit, implementing IAM policies, and configuring network ACLs to protect a multi-tier application.
Why candidates choose this
Candidates may confuse high availability with security because both involve redundancy and protection, but security focuses on access control and data protection rather than uptime and fault tolerance.
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.