Quick Answer
The answer is on-demand instances for SageMaker preprocessing to avoid failure. This is correct because on-demand instances provide a guaranteed, uninterrupted compute environment, which is essential for computationally intensive preprocessing jobs that cannot tolerate the risk of instance termination. Spot instances, while cost-effective, can be reclaimed by AWS with a two-minute warning, leading to job failures and data loss during preprocessing. On the AWS Certified Machine Learning Specialty MLS-C01 exam, this question tests your understanding of trade-offs between cost and reliability in SageMaker pipelines; a common trap is choosing spot instances for cost savings without considering the non-fault-tolerant nature of preprocessing tasks. Remember the memory tip: "Preprocessing is precious, so pay on-demand; spot is for spotty, restartable training."
This MLS-C01 practice question tests your understanding of machine learning implementation and operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 machine learning engineer is building a pipeline to preprocess data and train a model using Amazon SageMaker. The data is stored in Amazon S3 and the preprocessing step is computationally intensive. The engineer wants to minimize costs while ensuring that the preprocessing step does not fail due to instance termination. Which instance type should be used for the preprocessing step?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Reserved instances
Why wrong: Reserved instances require a 1- or 3-year commitment.
On-demand instances
On-demand instances are reliable and not terminated, ensuring the step completes.
A larger instance type to speed up processing
Why wrong: Larger instances cost more and do not address the reliability issue.
Spot instances
Why wrong: Spot instances can be terminated, causing the preprocessing step to fail.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
On-demand instances
Option C is correct because using on-demand instances guarantees that the instance will not be terminated during the preprocessing step. Option A is wrong because spot instances can be terminated, causing failures. Option B is wrong because reserved instances require a long-term commitment. Option D is wrong because a larger instance type increases costs unnecessarily.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Reserved instances
Why it's wrong here
Reserved instances require a 1- or 3-year commitment.
On-demand instances
Why this is correct
On-demand instances are reliable and not terminated, ensuring the step completes.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
A larger instance type to speed up processing
Why it's wrong here
Larger instances cost more and do not address the reliability issue.
Spot instances
Why it's wrong here
Spot instances can be terminated, causing the preprocessing step to fail.
Common exam traps
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
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
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related MLS-C01 NAT questions on configuration and troubleshooting.
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FAQ
Machine Learning Implementation and Operations — This question tests Machine Learning Implementation and Operations — Static NAT maps one inside address to one outside address..
The correct answer is: On-demand instances — Option C is correct because using on-demand instances guarantees that the instance will not be terminated during the preprocessing step. Option A is wrong because spot instances can be terminated, causing failures. Option B is wrong because reserved instances require a long-term commitment. Option D is wrong because a larger instance type increases costs unnecessarily.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related MLS-C01 NAT questions on configuration and troubleshooting.
Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Static NAT maps one inside address to one outside address.
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Last reviewed: Jun 20, 2026
This MLS-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 MLS-C01 exam.
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