CLF-C02 Cloud Concepts Practice Question
A company runs a stateless web application on a single Amazon EC2 instance in the us-east-1a Availability Zone. The application stores session data in an external Amazon ElastiCache cluster. Due to a power failure in the data center hosting us-east-1a, the EC2 instance becomes unavailable. The company wants to redesign the architecture so that the application recovers automatically in minutes if a single Availability Zone fails. Which design principle should the company implement?
⚠ Common exam trap
Candidates often confuse high-availability designs (multi-AZ Auto Scaling) with disaster recovery designs (multi-Region), or mistakenly think that instance-level protections like termination protection or larger instance types can mitigate an Availability Zone failure.
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
✓
Place the EC2 instance in an Auto Scaling group with a minimum capacity of 1, and configure the Auto Scaling group to span multiple Availability Zones.
Placing the EC2 instance in an Auto Scaling group with a minimum capacity of 1 and spanning multiple Availability Zones ensures that if us-east-1a fails, the Auto Scaling group automatically launches a new instance in a healthy Availability Zone (e.g., us-east-1b). Since the application is stateless and session data is stored externally in ElastiCache, the new instance can immediately serve traffic without data loss, achieving recovery within minutes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy the application across multiple AWS Regions and use Amazon Route 53 latency-based routing to failover.
Why it's wrong here
Multi-Region deployment with Route 53 latency-based routing addresses region-wide outages, which is disproportionate to the scenario of a single-AZ failure. Latency-based routing is only a routing policy that selects the endpoint with the lowest network latency; it does not automatically fail over unless combined with health checks and a separate failover routing policy. This solution adds significant cost, operational complexity, and cross-region data replication considerations when the appropriate correction is simply to deploy across multiple Availability Zones within the same Region.
When this WOULD be correct
This option would be correct if the question required the application to remain available during a regional outage (e.g., failure of an entire AWS Region) and needed to minimize latency for global users. For example: 'A company needs its application to be highly available across geographic regions and automatically route users to the nearest healthy endpoint.'
- ✓
Place the EC2 instance in an Auto Scaling group with a minimum capacity of 1, and configure the Auto Scaling group to span multiple Availability Zones.
Why this is correct
This is correct because an Auto Scaling group that spans multiple Availability Zones will automatically replace a failed instance in a healthy Availability Zone, ensuring the application remains available even if one AZ goes down.
- ✗
Use a larger EC2 instance type with dedicated tenancy to reduce the risk of hardware failure.
Why it's wrong here
Choosing a larger EC2 instance type or dedicated tenancy only changes the compute capacity or the physical isolation of the host; it does not alter the fundamental fact that the instance still resides in a single Availability Zone. If that AZ experiences an infrastructure failure, the instance becomes unavailable regardless of size or tenancy. Dedicated tenancy is a compliance and host-level isolation feature, not a high-availability mechanism, and a larger instance can even increase the blast radius of a single point of failure.
- ✗
Enable termination protection on the EC2 instance to prevent accidental stopping.
Why it's wrong here
Termination protection only prevents an instance from being terminated through the AWS console or API. It does not help if the instance becomes unavailable due to an underlying power or infrastructure failure in the Availability Zone.
When this WOULD be correct
A company wants to prevent a critical EC2 instance from being terminated by a script or user error, but does not need automatic failover across AZs. The question would specify that high availability is not required, only protection against accidental termination.
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.
✓Place the EC2 instance in an Auto Scaling group with a minimum capacity of 1, and configure the Auto Scaling group to span multiple Availability Zones.Correct answer▾
Why this is correct
This is correct because an Auto Scaling group that spans multiple Availability Zones will automatically replace a failed instance in a healthy Availability Zone, ensuring the application remains available even if one AZ goes down.
✗Deploy the application across multiple AWS Regions and use Amazon Route 53 latency-based routing to failover.Wrong answer — click to see why▾
Why this is wrong here
This option suggests deploying across multiple AWS Regions and using latency-based routing, which is overkill for recovering from a single Availability Zone failure. The question only requires recovery within minutes from a single AZ failure, not a regional disaster, making multi-Region deployment unnecessarily complex and costly.
★ When this WOULD be the correct answer
This option would be correct if the question required the application to remain available during a regional outage (e.g., failure of an entire AWS Region) and needed to minimize latency for global users. For example: 'A company needs its application to be highly available across geographic regions and automatically route users to the nearest healthy endpoint.'
Why candidates choose this
Candidates may think that using multiple Regions provides the highest level of availability and failover, but they overlook the specific requirement of recovering from a single Availability Zone failure, which can be achieved more simply and cost-effectively within a single Region.
✗Enable termination protection on the EC2 instance to prevent accidental stopping.Wrong answer — click to see why▾
Why this is wrong here
Termination protection prevents accidental deletion of an EC2 instance but does not provide automatic recovery from an Availability Zone failure. The instance remains in the failed AZ and cannot be restarted elsewhere.
★ When this WOULD be the correct answer
A company wants to prevent a critical EC2 instance from being terminated by a script or user error, but does not need automatic failover across AZs. The question would specify that high availability is not required, only protection against accidental termination.
Why candidates choose this
Candidates may confuse termination protection with high availability, thinking that preventing termination ensures the instance stays running, but it does not address the underlying failure of the AZ.
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.