DOP-C02 Resilient Cloud Solutions Practice Question
A company runs a stateless web application on EC2 instances behind an Application Load Balancer. To improve resilience, which configuration should be used for the EC2 instances?
⚠ Common exam trap
Candidates often think scaling vertically (larger instance) or using multiple instances in a single AZ is sufficient, but the DOP-C02 exam specifically tests the requirement for multi-AZ deployment to achieve resilience against AZ failures.
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 multiple EC2 instances across two or more Availability Zones
D is correct because deploying multiple EC2 instances across two or more Availability Zones (AZs) ensures high availability and fault tolerance. If one AZ fails, the Application Load Balancer (ALB) automatically routes traffic to healthy instances in other AZs, maintaining service continuity. This aligns with the AWS Well-Architected Framework's resilience best practices for stateless applications.
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 one EC2 instance with a larger instance type
Why it's wrong here
Does not improve availability.
- ✗
Use a single, large EC2 instance in one Availability Zone
Why it's wrong here
Single AZ is a single point of failure.
- ✗
Use multiple EC2 instances in one Availability Zone with health checks disabled
Why it's wrong here
Disabling health checks can route traffic to unhealthy instances.
- ✓
Use multiple EC2 instances across two or more Availability Zones
Why this is correct
Provides fault tolerance across AZs.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DOP-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 DOP-C02 exam.