DEA-C01 Data Operations and Support Practice Question
A company runs a data pipeline on Amazon EMR that processes terabytes of data daily. The pipeline reads from Amazon S3, performs transformations using Spark, and writes results back to S3. Recently, the data engineer noticed that the EMR cluster's spot instances are frequently reclaimed, causing job failures and delays. The cluster uses a mix of On-Demand and Spot instances. The engineer wants to minimize job interruptions while keeping costs low. The current configuration uses a single EMR cluster with a core node group of 10 On-Demand instances and a task node group of 20 Spot instances. The job failures occur during the shuffle phase when tasks on Spot instances are lost. The engineer has no control over when spot instances are reclaimed. Which action will MOST effectively reduce job failures while maintaining cost efficiency?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable EMR managed scaling to automatically add On-Demand instances when Spot instances are reclaimed.
Enabling EMR managed scaling allows the cluster to automatically add On-Demand instances when Spot instances are reclaimed, providing dynamic capacity to prevent job failures during the shuffle phase without significantly increasing costs. Option A is incorrect because increasing On-Demand instances in the core node group does not directly address the loss of Spot task nodes and can increase costs. Option B is incorrect because increasing the bid price to the On-Demand price does not guarantee avoidance of reclaims and still relies on Spot instances. Option C is incorrect because using only On-Demand instances would eliminate Spot savings and increase costs significantly.
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 number of On-Demand instances in the core node group to 20.
Why it's wrong here
This may help but does not dynamically replace lost Spot instances; also increases cost.
- ✗
Configure the task node group to use only Spot instances and increase the bid price to the On-Demand price.
Why it's wrong here
Increasing bid price to On-Demand price defeats cost savings and does not prevent reclamation.
- ✗
Change the task node group to use only On-Demand instances.
Why it's wrong here
Using only On-Demand would increase costs significantly.
- ✓
Enable EMR managed scaling to automatically add On-Demand instances when Spot instances are reclaimed.
Why this is correct
Managed scaling dynamically adjusts the cluster capacity, adding On-Demand instances to maintain cluster stability during Spot interruptions.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-C01 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 DEA-C01 exam.