Which AWS purchasing option fits a partial serverless migration?

CLF-C02 By islever Editorial Last updated

Compare AWS pricing models. Identify AWS compute services.

Short answer

D Compute Savings Plans discount EC2, Lambda, and Fargate usage under one upfront commitment, covering the partial serverless migration.

Question

A company's application is running on Amazon EC2 instances. The company is planning a partial migration to a serverless architecture in the next year and wants to pay for resources up front. Which AWS purchasing option will optimize the company's costs?
  1. Convertible Reserved Instances
  2. Spot Instances
  3. EC2 Instance Savings Plans
  4. Compute Savings Plan Correct Answer

Key Takeaways

The question tests whether you know which AWS discount model spans both EC2 and serverless compute — the trap is assuming Convertible Reserved Instances offer equivalent flexibility, when they only ever apply to EC2.

A company running on EC2 that plans a partial move to serverless within a year and wants to pay up front should choose Compute Savings Plans, because they discount EC2, Lambda, and Fargate under a single commitment. This page explains why Compute Savings Plans (D) beat Convertible Reserved Instances and EC2 Instance Savings Plans for a workload that will shift toward serverless.

Common mistake: Picking A (Convertible Reserved Instances) because "convertible" sounds flexible; that flexibility only lets you swap EC2 instance family, OS, or tenancy, so it cannot discount future Lambda or Fargate usage at all.

Expert Analysis

Why the Answer Is Correct

Compute Savings Plans (D) are the only option here that discounts the whole compute footprint the company is heading toward: they apply to EC2, AWS Lambda, and AWS Fargate usage, regardless of instance family, region, tenancy, or operating system. The company wants to pay up front, and Compute Savings Plans explicitly support an All Upfront payment option in exchange for a 1- or 3-year commitment, which maximizes the discount. Because the migration is only partial and spread over the next year, the plan's service-agnostic scope means the same commitment keeps saving money as EC2 usage shrinks and Lambda/Fargate usage grows. That directly satisfies the scenario's two constraints: upfront payment and a workload that becomes partly serverless.

Why the Other Options Are Wrong

A (Convertible Reserved Instances) is EC2-only — you can exchange them for a different instance family, OS, or tenancy, but they will never cover Lambda or Fargate, so the serverless portion of the migration earns no discount. C (EC2 Instance Savings Plans) locks the discount to a single instance family in a single region, so they are even narrower than Convertible RIs for a workload in transition. B (Spot Instances) offer deep discounts but are spare capacity that can be reclaimed with a two-minute interruption notice, and they have nothing to do with paying up front for a predictable commitment. In short, A and C are EC2-scoped and B is not a commitment-based upfront purchase at all.

Community Comment Notes

Supercell argued that Compute Savings Plans are the best fit here, and several voters agreed with "SERVERLESS = Compute Saving Plans" reasoning, echoing that the plan spans Lambda and Fargate. Dissent came mainly from ahadh7621, who posted that C is correct because the migration is only "a PARTIAL migration to serverless architecture" — but partial migrations still generate some serverless spend that EC2 Instance Savings Plans simply cannot discount. CharmaineBowman and f964633 backed A, describing how Convertible RIs let you "change instance families, operating systems, or tenancies," which is true but irrelevant to Lambda. chalaka summarized the winning rationale well: Compute Savings Plans "apply to a wide range of compute usage across Amazon EC2, AWS Lambda, and AWS Fargate."

Verdict

D is the correct choice: it is the only upfront-paid, commitment-based discount that follows the workload into serverless.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

When a stem mentions serverless, Lambda, or Fargate alongside EC2, treat "spanning services" as the deciding keyword and eliminate any EC2-only discount (Standard RIs, Convertible RIs, EC2 Instance Savings Plans). Only Compute Savings Plans cross the boundary from EC2 to serverless. Also note any "pay up front" phrasing — it points to a commitment-based plan, not Spot capacity.

Frequently Asked Questions

Do Compute Savings Plans cover Lambda and Fargate, not just EC2?

Yes. Compute Savings Plans apply to EC2, AWS Lambda, and AWS Fargate usage regardless of instance family, region, OS, or tenancy, which is why they suit a workload moving partly to serverless.

Why isn't the EC2 Instance Savings Plan (C) the answer for a partial migration?

It cuts costs only for a chosen EC2 instance family in a specific region, so any serverless usage from the migration — Lambda or Fargate — receives no discount at all.

More CLF-C02 FAQ →

Community Votes

D
69%
A
31%

69% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 11 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 11

  1. Supercell 👍 8 Answered D
    For a company that is planning a partial migration to a serverless architecture in the next year and wants to pay for resources up front to optimize costs, the best AWS purchasing option is: D. Compute Savings Plan The other options are less suitable for this scenario: A. Convertible Reserved Instances are a billing discount applied to specific EC2 instances and do not provide flexibility for serverless workloads. B. Spot Instances are suitable for fault-tolerant and flexible workloads but do not offer the ability to pay upfront for a commitment period. C. EC2 Instance Savings Plans provide discounts on EC2 instances only and do not extend to serverless services like Lambda or Fargate. By choosing a Compute Savings Plan and paying upfront, the company can optimize costs for their current EC2 usage and seamlessly transition to serverless services as their migration progresses, without losing the committed savings. This flexibility aligns well with their planned partial migration to a serverless architecture.
  2. ahadh7621 👍 3 Answered C
    C is correct and not D because its only a PARTIAL migration to serverless architecture
  3. CharmaineBowman 👍 2 Answered A
    Convertible Reserved Instances (RIs) allow customers to purchase EC2 capacity at a discounted rate compared to On-Demand pricing while providing the flexibility to change instance families, operating systems, or tenancies during the term of the reservation. This flexibility makes it ideal for a company that plans to migrate partially to serverless architecture, as it can adjust its RIs to match changing requirements over time. The upfront payment option can further optimize costs. Compute Savings Plans provide discounts on compute services, offering the flexibility to switch between EC2, AWS Lambda, and Fargate. However, they are better suited for fully serverless or containerized migrations rather than for managing upfront costs or EC2-focused workloads in a transitional phase.
  4. f964633 👍 2 Answered A
    The Convertible Reserved Instances option is the best choice because it allows the company to pay for resources up front, while also providing the flexibility to adjust their Reserved Instance purchases as they migrate to a serverless architecture. This flexibility is crucial as the company plans a partial migration, and Convertible Reserved Instances can help optimize their costs during this transition period.
  5. JoeTromundo 👍 2 Answered D
    SERVERLESS = Compute Saving Plans
Show 6 more comments
  1. chalaka 👍 1 Answered D
    D. Compute Savings Plans : provide the most flexibility because they apply to a wide range of compute usage across Amazon EC2, AWS Lambda, and AWS Fargate. This is especially beneficial for a company transitioning to a serverless architecture, as it allows them to benefit from cost savings across different AWS services, not just EC2. It also allows the company to commit to a consistent amount of usage (measured in dollars per hour) for a one- or three-year term, optimizing their costs.
  2. FMORADELL 👍 1 Answered A
    Convertible Reserved Instances provide flexibility for a company that is planning a partial migration to a serverless architecture. They allow the company to change the instance type, operating system, or tenancy during the term, offering more flexibility compared to Standard Reserved Instances
  3. Bajogi 👍 1 Answered D
    D. Compute Savings Plan Compute Savings Plans offer discounts on a variety of AWS compute services, including: Amazon EC2 AWS Fargate AWS Lambda Amazon ECS This makes them a flexible option for companies transitioning to a serverless architecture while still optimizing costs.
  4. AravindrajG 👍 1
    Compute Savings Plans offer discounts on a variety of AWS compute services, including: Amazon EC2 AWS Fargate AWS Lambda Amazon ECS Answer is D. Compute Savings Plan
  5. ShaiTay 👍 1 Answered D
    D. Compute Savings Plan - most flexible
  6. 91ad89c 👍 1 Answered A
    A. Convertible Reserved Instances

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