- A
Configure the Auto Scaling group to send a signal to CloudFormation using cfn-signal.
cfn-signal is used to notify CloudFormation of success or failure.
- B
Associate the Auto Scaling group with an ALB target group.
The target group defines health checks for the instances.
- C
Add a CreationPolicy to the Auto Scaling group.
CreationPolicy waits for a specified number of success signals.
- D
Add an UpdatePolicy to the Auto Scaling group with a rolling update configuration.
Why wrong: UpdatePolicy controls how updates are rolled out, not health check failure signaling.
- E
Use the AWS::CloudFormation::Init metadata to run a health check script.
Why wrong: This is used for configuration management, not for signaling CloudFormation.
Question 1,142 of 1,616
CloudFormation Stack Update Failure: cfn-signal and CreationPolicy
This DVA-C02 practice question tests your understanding of development with aws services. 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 company is using AWS CloudFormation to deploy a web application. The template creates an Auto Scaling group, an Application Load Balancer, and a security group. The developer wants to ensure that the stack update fails if the new Auto Scaling group instances fail health checks. Which THREE steps should the developer take? (Choose THREE.)
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
✓
Configure the Auto Scaling group to send a signal to CloudFormation using cfn-signal.
Option A is correct because `cfn-signal` sends a success or failure signal to CloudFormation, allowing the stack update to wait for the Auto Scaling group instances to pass health checks before proceeding. By combining `cfn-signal` with a `CreationPolicy`, CloudFormation can pause the stack creation or update until the signal is received, failing the operation if the signal indicates failure. This ensures that the stack update fails if the new instances do not pass health checks.
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.
- ✓
Configure the Auto Scaling group to send a signal to CloudFormation using cfn-signal.
Why this is correct
cfn-signal is used to notify CloudFormation of success or failure.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Associate the Auto Scaling group with an ALB target group.
Why this is correct
The target group defines health checks for the instances.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Add a CreationPolicy to the Auto Scaling group.
Why this is correct
CreationPolicy waits for a specified number of success signals.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Add an UpdatePolicy to the Auto Scaling group with a rolling update configuration.
Why it's wrong here
UpdatePolicy controls how updates are rolled out, not health check failure signaling.
- ✗
Use the AWS::CloudFormation::Init metadata to run a health check script.
Why it's wrong here
This is used for configuration management, not for signaling CloudFormation.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse `UpdatePolicy` with health check failure handling, but `UpdatePolicy` only manages the order of instance replacement, not the signaling of health check results to CloudFormation.
Detailed technical explanation
How to think about this question
The `cfn-signal` utility sends a signal to a CloudFormation wait condition, which is tied to a `CreationPolicy` or `UpdatePolicy`. The signal can include a unique ID and a status (SUCCESS or FAILURE), and CloudFormation waits for the specified number of signals before proceeding. If the signal indicates failure or times out, the stack operation rolls back, ensuring that only healthy instances are deployed. This mechanism is critical for blue/green deployments or canary testing where health checks must pass before traffic is routed.
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 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.
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FAQ
Questions learners often ask
What does this DVA-C02 question test?
Development with AWS Services — This question tests Development with AWS Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Configure the Auto Scaling group to send a signal to CloudFormation using cfn-signal. — Option A is correct because `cfn-signal` sends a success or failure signal to CloudFormation, allowing the stack update to wait for the Auto Scaling group instances to pass health checks before proceeding. By combining `cfn-signal` with a `CreationPolicy`, CloudFormation can pause the stack creation or update until the signal is received, failing the operation if the signal indicates failure. This ensures that the stack update fails if the new instances do not pass health checks.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This DVA-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 DVA-C02 exam.
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