CLF-C02 Billing, Pricing, and Support Practice Question
A company is migrating a steady-state web server to AWS. The server is expected to run continuously (24 hours a day, 7 days a week) for the next three years. The workload has predictable CPU and memory usage and does not experience significant spikes. The company wants to minimize the total cost of running this server over the three-year period. Which AWS EC2 pricing model should the company choose?
⚠ Common exam trap
AWS often tests the misconception that Spot Instances are always cheaper and can be used for any workload, but the trap here is that Spot Instances are interruptible and thus unsuitable for continuous, steady-state production servers.
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
✓
Standard Reserved Instances with a 3-year term and all upfront payment
Standard Reserved Instances with a 3-year term and all upfront payment provide the highest discount (up to 72% compared to On-Demand) for workloads that run continuously and predictably. Since this server will run 24/7 for three years with no significant spikes, a 3-year all upfront Reserved Instance minimizes total cost by locking in the lowest effective hourly rate.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
On-Demand Instances
Why it's wrong here
On-Demand Instances are billed per second (or per hour) with no upfront commitment, offering maximum flexibility for spiky or unknown workloads. However, for a predictable steady-state web server running continuously for 3 years, the cumulative On-Demand cost is substantially higher than any committed-use pricing model. Unlike Reserved Instances, which can reduce compute costs by up to 72% (with all upfront), On-Demand gives zero discount, making it the least cost-effective choice for this use case. The flexibility is irrelevant when the workload demand is constant.
When this WOULD be correct
For a short-term or unpredictable workload, such as a development server that will be used for only a few months or a batch processing job with variable demand, On-Demand Instances provide flexibility without long-term commitment.
- ✗
Spot Instances
Why it's wrong here
Spot Instances offer spare EC2 capacity at up to a 90% discount, but AWS can reclaim them with only a 2-minute warning when capacity is needed elsewhere. A steady-state web server requires 24/7 availability and cannot tolerate sudden interruptions without affecting users or requiring complex failover architecture. While you could design with Spot for a fault-tolerant stateless workload, this scenario describes a single steady-state server, so Spot's interruptibility makes it unsuitable. The risk of termination outweighs the cost savings for a continuously running, non-recoverable service.
When this WOULD be correct
For a fault-tolerant, stateless workload (e.g., batch processing, data analysis) that can handle interruptions and is flexible about start/end times, Spot Instances offer significant cost savings.
- ✓
Standard Reserved Instances with a 3-year term and all upfront payment
Why this is correct
Standard Reserved Instances provide a substantial discount over On-Demand pricing when you commit to a 1- or 3-year term. Paying all upfront gives the highest discount, making this the most cost-effective option for a predictable, long-running workload.
- ✗
Dedicated Hosts
Why it's wrong here
Dedicated Hosts provide physical servers dedicated to the customer, which is useful for software licensing or compliance requirements. However, they are more expensive than Reserved Instances and are not needed for a standard web server workload.
When this WOULD be correct
A company must run a workload that requires a specific physical server configuration for licensing or compliance reasons (e.g., per-socket or per-core licensing), and the workload runs continuously for several years. In that case, Dedicated Hosts would be the correct choice.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The CLF-C02 exam frequently reuses these exact scenarios with slightly different constraints.
✓Standard Reserved Instances with a 3-year term and all upfront paymentCorrect answer▾
Why this is correct
Standard Reserved Instances provide a substantial discount over On-Demand pricing when you commit to a 1- or 3-year term. Paying all upfront gives the highest discount, making this the most cost-effective option for a predictable, long-running workload.
✗On-Demand InstancesWrong answer — click to see why▾
Why this is wrong here
On-Demand Instances have no upfront commitment and are billed per hour, making them more expensive than Reserved Instances for a steady-state workload running continuously for three years.
★ When this WOULD be the correct answer
For a short-term or unpredictable workload, such as a development server that will be used for only a few months or a batch processing job with variable demand, On-Demand Instances provide flexibility without long-term commitment.
Why candidates choose this
Candidates may choose On-Demand because they are familiar with it and think it offers simplicity, without considering the significant cost savings of Reserved Instances for a predictable, long-term workload.
✗Spot InstancesWrong answer — click to see why▾
Why this is wrong here
Spot Instances can be interrupted with little notice, making them unsuitable for a steady-state web server that must run continuously for three years.
★ When this WOULD be the correct answer
For a fault-tolerant, stateless workload (e.g., batch processing, data analysis) that can handle interruptions and is flexible about start/end times, Spot Instances offer significant cost savings.
Why candidates choose this
Candidates may focus solely on the low cost of Spot Instances without considering the risk of interruption and the requirement for continuous, predictable uptime.
✗Dedicated HostsWrong answer — click to see why▾
Why this is wrong here
Dedicated Hosts provide physical servers dedicated for your use, which is unnecessary for a steady-state web server with predictable usage and no compliance requirements for physical isolation, leading to higher costs compared to Reserved Instances.
★ When this WOULD be the correct answer
A company must run a workload that requires a specific physical server configuration for licensing or compliance reasons (e.g., per-socket or per-core licensing), and the workload runs continuously for several years. In that case, Dedicated Hosts would be the correct choice.
Why candidates choose this
Candidates may think Dedicated Hosts offer better cost savings or performance for long-term workloads, but they overlook that Reserved Instances provide similar savings without the overhead of dedicated hardware.
Analysis generated from the official CLF-C02blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CLF-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 CLF-C02 exam.