- A
Software as a Service (SaaS)
Why wrong: SaaS does not provide control over OS.
- B
Infrastructure as a Service (IaaS)
IaaS provides virtual machines with full control over OS and applications.
- C
Platform as a Service (PaaS)
Why wrong: PaaS does not provide control over the underlying OS.
- D
Function as a Service (FaaS)
Why wrong: FaaS is event-driven and abstracts infrastructure completely.
Question 500 of 985
Infrastructure as a Service (IaaS): Full Control Over Operating System and Applications
This MS-900 practice question tests your understanding of describe cloud concepts. 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 company is evaluating cloud service models for running custom line-of-business applications. They need full control over the operating system and applications, but want to avoid managing physical hardware. Which cloud service model should they choose?
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
✓
Infrastructure as a Service (IaaS)
Infrastructure as a Service (IaaS) is the correct model because it provides virtualized computing resources over the internet, giving the customer full control over the operating system and applications while eliminating the need to manage physical hardware. Software as a Service (SaaS) offers pre-built applications with no control over the underlying OS. Platform as a Service (PaaS) abstracts the OS and runtime, offering a managed platform for applications, thus limiting OS control. Function as a Service (FaaS) runs individual functions in a serverless environment, abstracting servers entirely and providing no OS control.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Software as a Service (SaaS)
Why it's wrong here
SaaS does not provide control over OS.
- ✓
Infrastructure as a Service (IaaS)
Why this is correct
IaaS provides virtual machines with full control over OS and applications.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Platform as a Service (PaaS)
Why it's wrong here
PaaS does not provide control over the underlying OS.
- ✗
Function as a Service (FaaS)
Why it's wrong here
FaaS is event-driven and abstracts infrastructure completely.
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
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
What to study next
Got this wrong? Here's your next step.
Identify which MS-900 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Questions learners often ask
What does this MS-900 question test?
Describe cloud concepts — This question tests Describe cloud concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Infrastructure as a Service (IaaS) — Infrastructure as a Service (IaaS) is the correct model because it provides virtualized computing resources over the internet, giving the customer full control over the operating system and applications while eliminating the need to manage physical hardware. Software as a Service (SaaS) offers pre-built applications with no control over the underlying OS. Platform as a Service (PaaS) abstracts the OS and runtime, offering a managed platform for applications, thus limiting OS control. Function as a Service (FaaS) runs individual functions in a serverless environment, abstracting servers entirely and providing no OS control.
What should I do if I get this MS-900 question wrong?
Identify which MS-900 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
3 more ways this is tested on MS-900
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company uses a cloud provider that offers compute power as a service. The provider manages the physical servers, storage, and networking, but the company has full control over the operating system, applications, and configurations. Which cloud service model is being used?
easy- A.Software as a Service (SaaS)
- B.Platform as a Service (PaaS)
- ✓ C.Infrastructure as a Service (IaaS)
- D.Function as a Service (FaaS)
Why C: The scenario describes Infrastructure as a Service (IaaS), where the cloud provider manages the underlying physical infrastructure (servers, storage, networking), but the customer retains full control over the operating system, applications, and configurations. This aligns with the IaaS model as defined by NIST SP 800-145, which provides virtualized computing resources over the internet.
Variation 2. A company wants to reduce hardware maintenance costs by moving to the cloud. They need to maintain full control over the operating system, applications, and security configurations, but do not want to manage physical servers or data center facilities. Which cloud service model should they choose?
easy- A.Software as a Service (SaaS)
- B.Platform as a Service (PaaS)
- ✓ C.Infrastructure as a Service (IaaS)
- D.On-premises
Why C: Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet, allowing the company to deploy and manage their own operating systems, applications, and security configurations while offloading the physical hardware and data center management to the cloud provider. This model gives the highest level of control over the software stack without the burden of maintaining physical servers, aligning perfectly with the requirement to reduce hardware maintenance costs while retaining full administrative access.
Variation 3. A company wants to deploy a cloud solution where they have the maximum control over the operating system, installed software, and security configurations, but they do not want to manage physical servers or data center facilities. Which cloud service model best meets this requirement?
medium- ✓ A.Infrastructure as a Service (IaaS)
- B.Platform as a Service (PaaS)
- C.Software as a Service (SaaS)
- D.Hybrid cloud
Why A: Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet, giving the customer full administrative control over the operating system, installed software, and security configurations (e.g., firewall rules, patch management) while the cloud provider manages the physical servers, storage, and networking hardware. This model aligns with the requirement for maximum control without managing physical infrastructure.
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Last reviewed: Jun 21, 2026
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