The answer is that errors in the appspec.yml file or its lifecycle event scripts are the most likely cause. When CodeDeploy triggers lifecycle hooks like BeforeBlockTraffic, AfterInstall, or ValidateService, each script must exit with a zero code to signal success; a non-zero exit code immediately marks that instance as failed, and if too many instances fail, the entire deployment halts with the “too many instances failed” error. This scenario directly tests your understanding of the CodeDeploy agent’s behavior during a deployment to an Auto Scaling group, a common trap on the DOP-C02 exam where candidates mistakenly blame network connectivity or instance health—but the question explicitly states instances are healthy and can reach CodeDeploy, ruling out those causes. Remember the memory tip: “Zero to hero, non-zero to zero”—a script must exit zero for the instance to succeed, or the deployment goes to zero.
DOP-C02 SDLC Automation Practice Question
This DOP-C02 practice question tests your understanding of sdlc automation. 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 team 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.' The instances are healthy and can connect to the CodeDeploy service. 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 appspec.yml file or lifecycle event scripts have errors.
The appspec.yml file defines hooks like BeforeBlockTraffic, AfterInstall, etc. If these scripts exit with a non-zero code, the deployment fails.
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 Auto Scaling group launch configuration is incorrect.
Why it's wrong here
The instances are healthy, so launch config is probably correct.
✗
The deployment group is not configured with the correct service role.
Why it's wrong here
Role issues would cause connectivity errors, not script failures.
✓
The appspec.yml file or lifecycle event scripts have errors.
Why this is correct
Lifecycle event scripts must succeed; otherwise the deployment fails per instance.
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 target revision is not accessible from the instances.
Why it's wrong here
If not accessible, the error would be different (e.g., 'cannot download revision').
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.
SDLC Automation — This question tests SDLC Automation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The appspec.yml file or lifecycle event scripts have errors. — The appspec.yml file defines hooks like BeforeBlockTraffic, AfterInstall, etc. If these scripts exit with a non-zero code, the deployment fails.
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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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
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