The answer is that the account has reached the EC2 instance limit for the selected instance type in the region. This error occurs because AWS enforces service quotas that cap the number of running instances per instance family, and Auto Scaling groups cannot launch instances beyond that hard limit, even when the desired capacity demands more. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of how service quotas interact with Auto Scaling lifecycle actions, often appearing as a trap where candidates mistakenly blame the launch template, AMI, or subnet configuration. The key distinction is that the error message explicitly cites a quota issue, not a resource or configuration failure. A common memory tip is to think of quotas as a regional ceiling: no matter how high your desired capacity, you cannot exceed the instance family limit without requesting a quota increase.
DOP-C02 Incident and Event Response Practice Question
This DOP-C02 practice question tests your understanding of incident and event response. 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 DevOps engineer is troubleshooting an Auto Scaling group (ASG) that is not launching instances as expected. The ASG is configured with a launch template that uses an Amazon Linux 2 AMI. The engineer checks the EC2 Auto Scaling console and sees that the group's desired capacity is set to 2, but only 1 instance is running. The last scaling activity shows 'Failed to launch instance. Error: Your quota allows for 0 more running instance(s).' 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 account has reached the EC2 instance limit for the selected instance type in the region.
The error message 'Your quota allows for 0 more running instance(s)' directly indicates that the AWS account has reached its EC2 instance limit for the specific instance type in the region. Auto Scaling groups cannot launch instances beyond the service quota, regardless of the desired capacity. This is a common issue when the default limit (e.g., 5 or 20 instances per instance family) has been exhausted.
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 launch template has insufficient IAM permissions to create instances.
Why it's wrong here
A is wrong because insufficient permissions result in an 'Unauthorized' error, not a quota error.
✓
The account has reached the EC2 instance limit for the selected instance type in the region.
Why this is correct
B is correct because the error explicitly states quota for running instances is exceeded.
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 VPC subnet does not have enough available IP addresses.
Why it's wrong here
C is wrong because insufficient IP addresses would show a different error.
✗
There is an instance that is not passing health checks, preventing new instances.
Why it's wrong here
D is wrong because health check failures cause termination and replacement, not a quota error.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse IAM permissions with service quotas, or assume a VPC subnet IP shortage is the cause, when the explicit quota error message is the definitive clue.
Trap categories for this question
Command / output trap
C is wrong because insufficient IP addresses would show a different error.
Detailed technical explanation
How to think about this question
EC2 instance limits are per-region, per-instance-family (e.g., t3, m5), and can be increased via Service Quotas console or API. The Auto Scaling group's scaling activity records the exact AWS API error from the EC2 RunInstances call, which includes the quota violation code 'MaxInstanceCountExceeded'. In practice, this often occurs when using burstable instance types (e.g., t3.micro) that share a default limit of 20 across all Availability Zones in a region.
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.
Incident and Event Response — This question tests Incident and Event Response — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The account has reached the EC2 instance limit for the selected instance type in the region. — The error message 'Your quota allows for 0 more running instance(s)' directly indicates that the AWS account has reached its EC2 instance limit for the specific instance type in the region. Auto Scaling groups cannot launch instances beyond the service quota, regardless of the desired capacity. This is a common issue when the default limit (e.g., 5 or 20 instances per instance family) has been exhausted.
What should I do if I get this DOP-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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.