MS-900 Describe cloud concepts Practice Question
A company wants to use a cloud service where they can deploy their own custom applications without managing the underlying operating system or hardware. The cloud provider handles the runtime, middleware, and infrastructure. Which cloud service model best fits this requirement?
⚠ Common exam trap
Many candidates confuse PaaS with IaaS because both allow custom application deployment, but IaaS requires managing the OS and middleware, whereas PaaS abstracts those layers entirely.
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 model because it provides a managed environment where the company can deploy custom applications without managing the underlying OS, hardware, runtime, or middleware. The cloud provider handles all infrastructure and platform layers, allowing developers to focus solely on code and application logic.
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
Infrastructure as a Service (IaaS) supplies raw compute, storage, and networking as virtualized resources, but you remain responsible for installing and maintaining the operating system, runtime, and middleware. While you could deploy a custom application by managing those components yourself, it does not provide the managed runtime and service integration needed for a pure deployment-focused cloud platform. Therefore, IaaS is not the service model that lets you bypass OS administration.
- ✓
Platform as a Service (PaaS)
Why this is correct
Platform as a Service (PaaS) provides a fully managed application-hosting environment, including the runtime, programming model, data services, and scaling facilities. You deploy your own custom application code, while the provider handles the underlying OS, patching, and capacity; this directly matches the need to deploy custom apps without infrastructure management. This is why PaaS is the correct choice.
- ✗
Software as a Service (SaaS)
Why it's wrong here
Software as a Service (SaaS) delivers a ready-to-use, multi-tenant application through the browser or a client, with no capability for you to upload and run custom code in the provider's hosted environment. The provider owns the complete application stack from hardware to the application logic, so end users merely consume features rather than deploy their own software. Because the requirement is to deploy custom code, SaaS does not apply.
- ✗
Desktop as a Service (DaaS)
Why it's wrong here
Desktop as a Service (DaaS) hosts virtual desktop sessions—full operating system environments with user interfaces—rather than an application runtime for developers. It is meant for end-user remote work, not for deploying custom applications that execute behind a service interface. Since the goal is custom app deployment rather than delivering desktops, DaaS fails the requirement.
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