The answer is an incorrect or deregistered AMI ID. This is the most likely cause of a CloudFormation update failure because the stack update process validates resource properties against the current state of your AWS account; when the template references an AMI that no longer exists or has been deregistered in the target region, the update operation cannot launch or replace the EC2 instance, triggering the specific invalid AMI error. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of how CloudFormation handles immutable resource updates and the importance of verifying AMI IDs before stack operations—a common trap is confusing this with instance type mismatches or IAM permission errors, which produce different error messages. Remember the memory tip: "AMI must be alive to survive the update"—always confirm the AMI ID is current and available in the region before initiating a stack update.
DOP-C02 Configuration Management and IaC Practice Question
This DOP-C02 practice question tests your understanding of configuration management and iac. 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.
Network Topology
A CloudFormation stack update failed with the error shown. What is the most likely cause?
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 AMI ID specified in the template is incorrect or has been deregistered.
Option B is correct. The error message indicates that the AMI ID specified in the resource properties is invalid. This typically happens when the AMI ID does not exist in the region or has been deregistered. The stack update is trying to update the EC2 instance with a new AMI, but the AMI ID is incorrect. Option A is incorrect because the error is about the AMI ID, not the instance type. Option C is incorrect because the error is not about permissions. Option D is incorrect because the error is not about the stack name.
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 instance type t2.micro is not available in the region.
Why it's wrong here
The error specifically mentions imageId, not instanceType.
✗
The IAM role used by CloudFormation lacks ec2:RunInstances permissions.
Why it's wrong here
The error is about invalid AMI ID, not permissions.
✓
The AMI ID specified in the template is incorrect or has been deregistered.
Why this is correct
The error clearly states the imageId 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 stack name does not match the existing stack.
Why it's wrong here
The stack name is correct; the update failed on a resource.
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
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
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.
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 AMI ID specified in the template is incorrect or has been deregistered. — Option B is correct. The error message indicates that the AMI ID specified in the resource properties is invalid. This typically happens when the AMI ID does not exist in the region or has been deregistered. The stack update is trying to update the EC2 instance with a new AMI, but the AMI ID is incorrect. Option A is incorrect because the error is about the AMI ID, not the instance type. Option C is incorrect because the error is not about permissions. Option D is incorrect because the error is not about the stack name.
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.
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.
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Question Discussion
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