The answer is to use Amazon CloudWatch Events to trigger an AWS Lambda function when the EMR cluster reaches the 'TERMINATED' state, then check the job duration and alert if it exceeded three hours. This is correct because it provides event-driven emr job failure and timeout monitoring without polling, making it both cost-effective and operationally efficient—Lambda runs only when the cluster terminates, and you can compare the actual runtime against the threshold to detect both failures and timeouts. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your ability to decouple monitoring from job logic using native AWS services; a common trap is choosing a solution that modifies the EMR job code or uses continuous polling with CloudWatch alarms, which adds cost and complexity. Remember the key principle: let the state change itself trigger the check, not a scheduled poll. Memory tip: “Terminate triggers the Lambda—no polling, no panic.”
DOP-C02 Monitoring and Logging Practice Question
This DOP-C02 practice question tests your understanding of monitoring and logging. 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 running a batch processing job on Amazon EMR that writes results to an Amazon S3 bucket. The job runs daily and takes about 2 hours. The DevOps team wants to be alerted if the job fails or takes longer than 3 hours. Which solution is the MOST cost-effective and operationally efficient?
Configure Amazon Simple Notification Service (SNS) directly from the EMR job to send notifications on completion.
Why wrong: Not built-in; requires custom code.
B
Use Amazon CloudWatch Events to trigger an AWS Lambda function when the EMR cluster changes to 'TERMINATED' state, then check the job duration and send an alert if it exceeded 3 hours.
Cost-effective and event-driven.
C
Create a CloudWatch alarm on the EMR cluster's EC2 instance CPUUtilization metric to detect abnormal runtime.
Why wrong: CPUUtilization does not indicate job duration.
D
Use Amazon CloudWatch Logs to monitor the job's log stream and create a metric filter for 'FAILED' messages.
Why wrong: Requires logs to be in CloudWatch Logs and does not measure duration.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use Amazon CloudWatch Events to trigger an AWS Lambda function when the EMR cluster changes to 'TERMINATED' state, then check the job duration and send an alert if it exceeded 3 hours.
Option B is correct because it uses CloudWatch Events to detect the EMR cluster's 'TERMINATED' state, which triggers a Lambda function that can check the job duration against the 3-hour threshold and send an alert via SNS if needed. This approach is cost-effective (no polling, event-driven) and operationally efficient, as it decouples monitoring from the job itself and handles both failure and timeout scenarios without modifying the EMR job code.
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 Amazon Simple Notification Service (SNS) directly from the EMR job to send notifications on completion.
Why it's wrong here
Not built-in; requires custom code.
✓
Use Amazon CloudWatch Events to trigger an AWS Lambda function when the EMR cluster changes to 'TERMINATED' state, then check the job duration and send an alert if it exceeded 3 hours.
Why this is correct
Cost-effective and event-driven.
Related concept
Read the scenario before looking for a memorised answer.
✗
Create a CloudWatch alarm on the EMR cluster's EC2 instance CPUUtilization metric to detect abnormal runtime.
Why it's wrong here
CPUUtilization does not indicate job duration.
✗
Use Amazon CloudWatch Logs to monitor the job's log stream and create a metric filter for 'FAILED' messages.
Why it's wrong here
Requires logs to be in CloudWatch Logs and does not measure duration.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume CloudWatch Logs metric filters (Option D) are the simplest way to detect failures, but they miss the timeout requirement and require log-based failure patterns, whereas event-driven state monitoring (Option B) inherently captures both failure and duration scenarios without custom logging.
Detailed technical explanation
How to think about this question
Under the hood, CloudWatch Events (now part of Amazon EventBridge) can match EMR cluster state changes via the 'EMR Cluster State Change' event pattern, which includes fields like 'state' (e.g., 'TERMINATED') and 'stateChangeReason'. The Lambda function can parse the event's 'startTime' and 'endTime' to compute duration, then compare it to the 3-hour threshold. A subtle behavior: if the job fails early (e.g., after 10 minutes), the cluster still transitions to 'TERMINATED', so the Lambda must also check the 'stateChangeReason' for failure codes (e.g., 'STEPS_FAILURE') to alert on failures, not just timeouts.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
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.
Monitoring and Logging — This question tests Monitoring and Logging — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use Amazon CloudWatch Events to trigger an AWS Lambda function when the EMR cluster changes to 'TERMINATED' state, then check the job duration and send an alert if it exceeded 3 hours. — Option B is correct because it uses CloudWatch Events to detect the EMR cluster's 'TERMINATED' state, which triggers a Lambda function that can check the job duration against the 3-hour threshold and send an alert via SNS if needed. This approach is cost-effective (no polling, event-driven) and operationally efficient, as it decouples monitoring from the job itself and handles both failure and timeout scenarios without modifying the EMR job code.
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.
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.