The answer is to launch EC2 instances in a second Availability Zone and register them with the NLB target group. This is correct because NLB cross-zone high availability is achieved by distributing traffic across healthy targets in multiple zones; the NLB inherently balances load across all registered targets regardless of zone, so simply adding instances in a new zone eliminates the single point of failure without requiring any application rearchitecture. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this question tests your understanding that NLBs are zone-aware but not zone-dependent—a common trap is thinking you need an Application Load Balancer or instance scaling, but the core concept is that high availability requires geographic redundancy at the target level, not the load balancer type. Remember the memory tip: "NLB doesn't care about zones, only healthy targets"—so to survive a zone outage, you must have targets in more than one zone.
DOP-C02 Resilient Cloud Solutions Practice Question
This DOP-C02 practice question tests your understanding of resilient cloud solutions. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company uses an NLB to distribute traffic to a fleet of EC2 instances in a single Availability Zone. During a recent AWS outage in that zone, the application became completely unavailable. The company wants to achieve high availability without rearchitecting the application. Which change is MOST appropriate?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Launch EC2 instances in a second Availability Zone and register them with the NLB target group
Option D is correct because NLB automatically routes traffic to healthy targets across Availability Zones when targets are registered. Option A is wrong because ALB is not required; NLB can handle multi-AZ. Option B is wrong because instance type does not affect availability. Option C is wrong because it does not address zone failure.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 a larger instance type and enable detailed CloudWatch monitoring
Why it's wrong here
Does not provide fault tolerance across zones.
✗
Replace the NLB with an Application Load Balancer and enable cross-zone load balancing
Why it's wrong here
NLB also supports cross-zone; replacing is unnecessary.
✗
Create an Auto Scaling group with a scheduled scaling policy to add instances during peak hours
Why it's wrong here
Does not address zone failure.
✓
Launch EC2 instances in a second Availability Zone and register them with the NLB target group
Why this is correct
Distributes traffic across zones, providing high availability.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
Identify which DOP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Resilient Cloud Solutions — This question tests Resilient Cloud Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Launch EC2 instances in a second Availability Zone and register them with the NLB target group — Option D is correct because NLB automatically routes traffic to healthy targets across Availability Zones when targets are registered. Option A is wrong because ALB is not required; NLB can handle multi-AZ. Option B is wrong because instance type does not affect availability. Option C is wrong because it does not address zone failure.
What should I do if I get this DOP-C02 question wrong?
Identify which DOP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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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.
Question Discussion
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