Question 1,507 of 1,546
Cost and Performance OptimizationhardMultiple ChoiceObjective-mapped

SOA-C02 Spot Instances Practice Question

This SOA-C02 practice question tests your understanding of cost and performance optimization. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. A key principle to apply: spot Instances. 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 has a data processing job that runs on Amazon EMR. The job takes 2 hours to complete and runs once per day. The SysOps administrator wants to reduce costs without affecting the completion time. Which strategy is MOST effective?

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

Use Spot Instances for the task nodes in the EMR cluster.

The most cost-effective strategy is to use Spot Instances for the task nodes in the EMR cluster. Task nodes are fault-tolerant because they only process data and do not store persistent data. Spot Instances offer significant discounts (up to 90%) compared to On-Demand instances. Since the job runs for 2 hours, it is short enough that the risk of interruption is manageable, and EMR can automatically relaunch tasks if interrupted. Option B (smaller number of larger instances) may reduce parallelism and could increase runtime, potentially not meeting the 2-hour requirement. Option C (reducing core nodes) would affect HDFS storage and may increase job duration. Option D (Compute Savings Plans) would require a 1- or 3-year commitment and may not be optimal for a single daily job; Spot Instances provide greater savings without commitment.

Key principle: Spot Instances

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Use Spot Instances for the task nodes in the EMR cluster.

    Why this is correct

    Correct. Spot Instances for task nodes reduce costs significantly because they are cheaper and fault-tolerant. The job can tolerate interruptions.

    Related concept

    Spot Instances

  • Use a smaller number of larger EC2 instances.

    Why it's wrong here

    Incorrect. Using larger instances may reduce per-instance cost but may decrease parallelism and increase job duration, possibly exceeding 2 hours.

  • Reduce the number of core nodes.

    Why it's wrong here

    Incorrect. Reducing core nodes affects HDFS storage and may slow down the job due to reduced data locality and compute capacity.

  • Purchase Compute Savings Plans for the EMR cluster.

    Why it's wrong here

    Incorrect. While Savings Plans can reduce costs, they require a long-term commitment and offer less savings than Spot Instances for short, fault-tolerant workloads.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.

Detailed technical explanation

How to think about this question

Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.

KKey Concepts to Remember

  • Spot Instances
  • EMR task nodes
  • Fault tolerance

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

Spot Instances

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.

Review spot Instances, then practise related SOA-C02 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this SOA-C02 question test?

Cost and Performance Optimization — This question tests Cost and Performance Optimization — Spot Instances.

What is the correct answer to this question?

The correct answer is: Use Spot Instances for the task nodes in the EMR cluster. — The most cost-effective strategy is to use Spot Instances for the task nodes in the EMR cluster. Task nodes are fault-tolerant because they only process data and do not store persistent data. Spot Instances offer significant discounts (up to 90%) compared to On-Demand instances. Since the job runs for 2 hours, it is short enough that the risk of interruption is manageable, and EMR can automatically relaunch tasks if interrupted. Option B (smaller number of larger instances) may reduce parallelism and could increase runtime, potentially not meeting the 2-hour requirement. Option C (reducing core nodes) would affect HDFS storage and may increase job duration. Option D (Compute Savings Plans) would require a 1- or 3-year commitment and may not be optimal for a single daily job; Spot Instances provide greater savings without commitment.

What should I do if I get this SOA-C02 question wrong?

Review spot Instances, then practise related SOA-C02 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

Spot Instances

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Last reviewed: Jun 20, 2026

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This SOA-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 SOA-C02 exam.