- A
Infrastructure as a Service (IaaS)
Why wrong: Incorrect. IaaS provides virtual machines but the customer must manage the operating system and applications.
- B
Platform as a Service (PaaS)
Correct. PaaS abstracts the underlying infrastructure, allowing developers to focus on code while the provider manages server, OS, and scaling.
- C
Software as a Service (SaaS)
Why wrong: Incorrect. SaaS provides fully managed applications (e.g., email, Office apps) and is not suitable for deploying custom code.
- D
On-premises deployment
Why wrong: Incorrect. On-premises requires the organization to manage all hardware and software, which contradicts the requirement to avoid infrastructure management.
Question 52 of 985
PaaS: Custom Web Apps with Auto-Scaling and Managed Infrastructure
This MS-900 practice question tests your understanding of describe cloud concepts. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 development team wants to deploy a custom web application to the cloud. They want to upload their code and let the cloud provider handle server infrastructure, operating system updates, and automatic scaling. Which cloud service model best fits this requirement?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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
✓
Platform as a Service (PaaS)
Platform as a Service (PaaS) is the correct choice because it provides a managed hosting environment where the development team can upload their custom web application code without managing the underlying server infrastructure, operating system updates, or scaling. Azure App Service, a PaaS offering, automatically handles OS patching, load balancing, and auto-scaling based on demand, aligning perfectly with the requirement to let the cloud provider handle these tasks.
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.
- ✗
Infrastructure as a Service (IaaS)
Why it's wrong here
Incorrect. IaaS provides virtual machines but the customer must manage the operating system and applications.
- ✓
Platform as a Service (PaaS)
Why this is correct
Correct. PaaS abstracts the underlying infrastructure, allowing developers to focus on code while the provider manages server, OS, and scaling.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Software as a Service (SaaS)
Why it's wrong here
Incorrect. SaaS provides fully managed applications (e.g., email, Office apps) and is not suitable for deploying custom code.
- ✗
On-premises deployment
Why it's wrong here
Incorrect. On-premises requires the organization to manage all hardware and software, which contradicts the requirement to avoid infrastructure management.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse IaaS with PaaS, mistakenly thinking that IaaS also abstracts OS updates and scaling, but IaaS still requires the user to manage the OS and configure scaling manually, unlike PaaS which fully automates these responsibilities.
Detailed technical explanation
How to think about this question
PaaS abstracts the runtime environment, typically using containers or sandboxed processes (e.g., Azure App Service runs on a managed Windows or Linux container with IIS or Nginx). Auto-scaling in PaaS relies on metrics like CPU usage or request queue depth, triggering horizontal scaling by adding more instances behind a load balancer, while the platform automatically applies OS patches during predefined maintenance windows without user intervention.
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.
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
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.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Describe cloud concepts — study guide chapter
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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: Platform as a Service (PaaS) — Platform as a Service (PaaS) is the correct choice because it provides a managed hosting environment where the development team can upload their custom web application code without managing the underlying server infrastructure, operating system updates, or scaling. Azure App Service, a PaaS offering, automatically handles OS patching, load balancing, and auto-scaling based on demand, aligning perfectly with the requirement to let the cloud provider handle these tasks.
What should I do if I get this MS-900 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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
6 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 development team wants to build a custom web application. They choose a cloud service that provides the runtime environment, operating system, and middleware, but the team is responsible for writing and deploying their own code. The provider automatically applies patches to the underlying infrastructure. Which cloud service model best describes this approach?
medium- A.Infrastructure as a Service (IaaS)
- ✓ B.Platform as a Service (PaaS)
- C.Software as a Service (SaaS)
- D.Function as a Service (FaaS)
Why B: Platform as a Service (PaaS) provides the runtime environment, operating system, and middleware, allowing developers to focus on writing and deploying their own code while the cloud provider manages the underlying infrastructure, including automatic patching. This model abstracts the hardware and OS layer, giving the team full control over application code but not the platform stack.
Variation 2. A startup wants to build a custom application with minimal infrastructure management and only pay for the resources consumed. Which cloud service model should they choose?
hard- A.Functions as a Service (FaaS)
- B.Software as a Service (SaaS)
- C.Infrastructure as a Service (IaaS)
- ✓ D.Platform as a Service (PaaS)
Why D: Option D (Platform as a Service, PaaS) is correct because it allows you to build and deploy custom applications without managing the underlying infrastructure, and you only pay for the resources you consume. Option A (Functions as a Service, FaaS) is a subset of PaaS focused on event-driven functions and is less suitable for a full custom application. Option B (Software as a Service, SaaS) provides ready-to-use applications, not a platform for custom development. Option C (Infrastructure as a Service, IaaS) requires you to manage virtual machines and pay for allocated resources regardless of actual usage.
Variation 3. A development team wants to deploy a custom web application. They choose a cloud service that provides the operating system, web server, and database management system. The team is responsible only for uploading and managing their application code. Which cloud service model does this represent?
medium- A.Infrastructure as a Service (IaaS)
- ✓ B.Platform as a Service (PaaS)
- C.Software as a Service (SaaS)
- D.Function as a Service (FaaS)
Why B: This scenario describes Platform as a Service (PaaS) because the cloud provider manages the underlying infrastructure—operating system, web server, and database management system—while the development team is responsible only for deploying and managing their custom application code. PaaS abstracts the platform layer, allowing developers to focus on code without worrying about OS patches, web server configuration, or database administration.
Variation 4. A startup wants to focus only on developing and deploying its application code without managing underlying servers or operating systems. Which cloud service model best fits this need?
easy- A.Infrastructure as a Service (IaaS)
- ✓ B.Platform as a Service (PaaS)
- C.Software as a Service (SaaS)
- D.On-premises deployment
Why B: Platform as a Service (PaaS) is the correct choice because it abstracts the underlying infrastructure, including servers, operating systems, and runtime environments, allowing the startup to focus solely on developing and deploying application code. With PaaS, the cloud provider manages the OS patching, hardware scaling, and middleware, while the customer only manages the application and data. This directly matches the requirement of not managing servers or operating systems.
Variation 5. A company wants to use a cloud service where they can develop and run applications without managing the underlying infrastructure, including servers, operating systems, or storage. They only need to upload their code and the provider handles scaling and availability. Which cloud service model best describes this approach?
easy- A.Infrastructure as a Service (IaaS)
- ✓ B.Platform as a Service (PaaS)
- C.Software as a Service (SaaS)
- D.On-premises deployment
Why B: Platform as a Service (PaaS) provides a managed hosting environment where developers can deploy applications without worrying about the underlying infrastructure. The provider automatically handles server provisioning, OS patching, storage management, and scaling based on demand. In this scenario, the company only needs to upload code, which is the defining characteristic of PaaS.
Variation 6. A development team uses a cloud service to run applications where the provider manages the runtime environment, operating system, and middleware. The team only writes and uploads code. Which service model are they using?
medium- A.IaaS (Infrastructure as a Service)
- ✓ B.PaaS (Platform as a Service)
- C.SaaS (Software as a Service)
- D.FaaS (Function as a Service)
Why B: The scenario describes the team writing and uploading code while the provider manages the runtime environment, operating system, and middleware. This is the defining characteristic of Platform as a Service (PaaS), where the cloud provider abstracts the underlying infrastructure and platform layers, allowing developers to focus solely on application code. In PaaS, the provider handles OS patching, runtime updates, and middleware configuration, which matches the description exactly.
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Last reviewed: Jun 11, 2026
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