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 company runs a critical application on Amazon ECS with Fargate launch type. The application uses an Application Load Balancer (ALB) in front. During a load test, the team notices a sudden increase in 5xx errors from the ALB, and some tasks become unhealthy. The task logs show occasional 'OutOfMemoryError' exceptions. The task definition currently has 512 CPU units and 1024 MiB memory. What should the team do to mitigate the issue while maintaining a cost-effective approach?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the task definition memory to 2048 MiB while keeping CPU at 512 units.
Option B is correct because the application is experiencing OutOfMemoryError, indicating the current 1024 MiB memory allocation is insufficient. Increasing memory to 2048 MiB while keeping CPU at 512 units directly resolves the memory constraint without unnecessary CPU cost. ECS Fargate allows independent scaling of CPU and memory within valid combinations, and this change maintains a cost-effective approach by only increasing the resource that is actually constrained.
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.
✗
Increase the task definition CPU to 1024 units and memory to 2048 MiB.
Why it's wrong here
More CPU is unnecessary if the issue is memory, and cost increases more.
✓
Increase the task definition memory to 2048 MiB while keeping CPU at 512 units.
Why this is correct
This directly addresses the memory error without wasting resources on extra CPU.
Related concept
Read the scenario before looking for a memorised answer.
✗
Configure the ECS service to use a rolling update with a longer health check grace period.
Why it's wrong here
This does not fix the underlying memory issue.
✗
Decrease the task definition memory to 512 MiB to force garbage collection more frequently.
Why it's wrong here
Reducing memory would likely increase OutOfMemoryErrors.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may assume both CPU and memory must be increased together (Option A) or that a deployment strategy change (Option C) can mitigate resource exhaustion, when in fact the root cause is a memory limit that must be raised independently.
Detailed technical explanation
How to think about this question
In ECS Fargate, the task-level memory is a hard limit; when the container exceeds it, the kernel's OOM killer terminates the process, leading to OutOfMemoryError and unhealthy tasks. The ALB 5xx errors occur because the target group health checks fail when tasks become unhealthy or crash. Fargate supports specific CPU/memory combinations (e.g., 512 CPU with 1024, 2048, or 4096 MiB memory), so increasing memory to 2048 MiB is a valid and cost-effective fix that stays within the same CPU tier.
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.
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: Increase the task definition memory to 2048 MiB while keeping CPU at 512 units. — Option B is correct because the application is experiencing OutOfMemoryError, indicating the current 1024 MiB memory allocation is insufficient. Increasing memory to 2048 MiB while keeping CPU at 512 units directly resolves the memory constraint without unnecessary CPU cost. ECS Fargate allows independent scaling of CPU and memory within valid combinations, and this change maintains a cost-effective approach by only increasing the resource that is actually constrained.
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.
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Question Discussion
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