The answer is that the EC2 key pair 'myKeyPair' does not exist in the region where the stack is being created. This is the most likely cause of the CloudFormation key pair validation error because CloudFormation performs a real-time existence check on the specified key pair name against the target region’s EC2 resources at stack creation time; if the key pair is missing, the service immediately fails the resource with a CREATE_FAILED status reason clearly indicating the key pair was not found. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of CloudFormation’s dependency validation and regional resource scoping—a common trap is assuming the key pair name is globally unique or that CloudFormation will create it automatically. Remember that key pairs are region-specific and must be pre-created or imported before referencing them in a template. Memory tip: “Key pairs are regional, not global—if it’s missing, the stack will fall.”
DOP-C02 Configuration Management and IaC Practice Question
This DOP-C02 practice question tests your understanding of configuration management and iac. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Network Topology
A DevOps engineer attempted to create a CloudFormation stack and it failed. The engineer runs the 'describe-stack-events' command and sees the output above. What is the most likely cause of the failure?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The EC2 key pair 'myKeyPair' does not exist in the region where the stack is being created.
The 'describe-stack-events' output shows a 'CREATE_FAILED' event for the EC2 instance resource with the status reason indicating that the key pair 'myKeyPair' was not found. CloudFormation validates the existence of the specified EC2 key pair in the target region at creation time; if the key pair does not exist, the stack creation fails immediately. This is a common validation error when the key pair name is misspelled, belongs to a different region, or has not been created beforehand.
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.
✓
The EC2 key pair 'myKeyPair' does not exist in the region where the stack is being created.
Why this is correct
The error message clearly states the key name is invalid.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The AMI ID specified in the template is not available in the region.
Why it's wrong here
The error is about key name, not AMI.
✗
The CloudFormation template has a syntax error in the EC2 instance definition.
Why it's wrong here
The error is a runtime validation error, not a syntax error.
✗
The security group specified for the EC2 instance does not exist.
Why it's wrong here
The error is about key name, not security group.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse a missing key pair with other common EC2 launch failures like AMI unavailability or security group issues, but the specific error message in the stack events directly points to the key pair name as the root cause.
Detailed technical explanation
How to think about this question
CloudFormation performs resource creation in dependency order, and for EC2 instances, it checks the existence of the specified key pair in the target region by calling the EC2 DescribeKeyPairs API. If the key pair is not found, the API returns an 'InvalidKeyPair.NotFound' error, which CloudFormation surfaces as a CREATE_FAILED event. This behavior is region-specific because key pairs are scoped to a single AWS region and cannot be shared across regions without manual export/import.
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.
TExam Day Tips
→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
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Configuration Management and IaC — This question tests Configuration Management and IaC — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The EC2 key pair 'myKeyPair' does not exist in the region where the stack is being created. — The 'describe-stack-events' output shows a 'CREATE_FAILED' event for the EC2 instance resource with the status reason indicating that the key pair 'myKeyPair' was not found. CloudFormation validates the existence of the specified EC2 key pair in the target region at creation time; if the key pair does not exist, the stack creation fails immediately. This is a common validation error when the key pair name is misspelled, belongs to a different region, or has not been created beforehand.
What should I do if I get this DOP-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.