This CV0-004 practice question tests your understanding of deployment. 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.
A cloud administrator is debugging a failed CloudFormation stack creation. The exhibit shows the stack events. 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.
The instance type is not supported in the region.
Why wrong: No error about instance type.
The stack name already exists.
Why wrong: Stack creation in progress, not duplicate.
The AMI ID is incorrect.
Why wrong: No AMI error.
The referenced security group does not exist in the chosen VPC.
The error explicitly mentions invalid groupId.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The referenced security group does not exist in the chosen VPC.
The stack creation fails with a 'CREATE_FAILED' status on the security group resource, and the error message indicates that the security group does not exist in the specified VPC. This is a common issue when a CloudFormation template references a security group by ID or name that is not present in the target VPC, causing the resource creation to fail. The stack events show the security group resource as the point of failure, confirming that the referenced security group is missing.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The instance type is not supported in the region.
Why it's wrong here
No error about instance type.
The stack name already exists.
Why it's wrong here
Stack creation in progress, not duplicate.
The AMI ID is incorrect.
Why it's wrong here
No AMI error.
The referenced security group does not exist in the chosen VPC.
Why this is correct
The error explicitly mentions invalid groupId.
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.
Common exam traps
CompTIA often tests the ability to read CloudFormation stack events and correlate the failing resource with the specific error message, rather than assuming a generic failure like an incorrect AMI or instance type.
Detailed technical explanation
In AWS CloudFormation, when a template references a security group by its logical ID or physical ID, the stack creation will attempt to validate that the security group exists in the specified VPC before creating dependent resources. If the security group is missing, the resource creation fails with a 'dependency violation' or 'resource not found' error. This is often encountered when using cross-stack references or when the security group is deleted or created in a different VPC than the one specified in the template's VPC configuration.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the CV0-004 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Deployment — This question tests Deployment — Read the scenario before looking for a memorised answer..
The correct answer is: The referenced security group does not exist in the chosen VPC. — The stack creation fails with a 'CREATE_FAILED' status on the security group resource, and the error message indicates that the security group does not exist in the specified VPC. This is a common issue when a CloudFormation template references a security group by ID or name that is not present in the target VPC, causing the resource creation to fail. The stack events show the security group resource as the point of failure, confirming that the referenced security group is missing.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This CV0-004 practice question is part of Courseiva's free CompTIA 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 CV0-004 exam.
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