This DVA-C02 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 company uses AWS CodeDeploy to deploy an application to an Auto Scaling group. The deployment fails with the error 'The overall deployment failed because too many individual instances failed deployment, too few healthy instances are available for deployment, or some instances in your deployment group are experiencing problems.' Which of the following 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 new application version fails the configured health checks on the instances.
The error message indicates that instances failed deployment, which is most commonly caused by the new application version failing the health checks configured in the deployment group. CodeDeploy uses these health checks (e.g., ELB health checks or custom scripts) to determine if an instance is healthy after deployment; if the application crashes or returns non-200 status codes, CodeDeploy marks the instance as failed and aborts the deployment.
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 new application version fails the configured health checks on the instances.
Why this is correct
Health check failures cause the deployment to roll back.
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 deployment group does not exist.
Why it's wrong here
The deployment group must exist for deployment to start.
✗
The IAM role for CodeDeploy does not have sufficient permissions.
Why it's wrong here
IAM issues cause different error messages.
✗
The CodeDeploy agent is not installed on the instances.
Why it's wrong here
Agent issues cause instance failures but not necessarily the overall error.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse deployment failures caused by health check failures with infrastructure issues like missing IAM roles or agents, but the specific error message about 'too many individual instances failed deployment' directly points to application-level health check failures, not permission or agent problems.
Detailed technical explanation
How to think about this question
CodeDeploy performs health checks by default using the target group's health check settings (e.g., HTTP 200 on a specific path) or via a custom script defined in the AppSpec file's 'Hooks' section. The deployment fails when the number of healthy instances drops below the configured 'minimumHealthyHosts' threshold (e.g., 75% or 1 instance), which is calculated using either 'hostCount' or 'fleetPercent' values. In Auto Scaling groups, CodeDeploy also integrates with lifecycle hooks to ensure instances are properly registered 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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Deployment — This question tests Deployment — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The new application version fails the configured health checks on the instances. — The error message indicates that instances failed deployment, which is most commonly caused by the new application version failing the health checks configured in the deployment group. CodeDeploy uses these health checks (e.g., ELB health checks or custom scripts) to determine if an instance is healthy after deployment; if the application crashes or returns non-200 status codes, CodeDeploy marks the instance as failed and aborts the deployment.
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.
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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