What Is Infrastructure as a Service (IaaS)?
A company wants to deploy a custom web application in the cloud. They need full control over the operating system and software stack, including the ability to install and configure the web server, database, and security patches. They do not want to manage the underlying physical hardware or hypervisor. Which cloud service model best meets their requirements?
Quick Answer
The answer is Infrastructure as a Service (IaaS). IaaS is the correct choice because it delivers virtualized computing resources over the internet, granting you full control over the operating system, middleware, and applications—exactly what is needed for custom software stacks—while the cloud provider handles the underlying physical hardware and hypervisor. On the CompTIA A+ Core 1 220-1101 exam, this scenario tests your ability to distinguish cloud service models by their level of management responsibility; a common trap is confusing IaaS with Platform as a Service (PaaS), which restricts OS control. Remember the memory tip: IaaS gives you the keys to the virtual machine, so you own the OS and software, but the provider owns the physical rack.
⚠ Common exam trap
Watch out — candidates often confuse PaaS with IaaS because both involve cloud deployment, but PaaS removes OS-level control, which is the critical differentiator in this scenario.
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) provides virtualized computing resources over the internet, giving the customer full control over the operating system, middleware, and applications while the cloud provider manages the underlying physical hardware and hypervisor. This matches the requirement for full OS and software stack control without managing physical infrastructure.
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 this is correct
IaaS provides virtual machines with full control of the operating system, web server, database and patch management, while the provider handles physical hardware and hypervisor. This matches the stated requirement for OS-level control without managing underlying infrastructure.
- ✗
Platform as a Service (PaaS)
Why it's wrong here
PaaS manages the operating system and runtime, so the customer cannot install or configure the web server, database or security patches themselves. It fits developers who deploy code only and want the provider to handle patching and scaling of the platform beneath.
- ✗
Software as a Service (SaaS)
Why it's wrong here
SaaS delivers a finished application managed entirely by the provider, so the customer cannot install a web server, database or patches. It suits scenarios where an organisation simply consumes ready-made software such as email or CRM and wants no control over the stack.
- ✗
Desktop as a Service (DaaS)
Why it's wrong here
DaaS streams a virtual desktop to end users, providing no server-side runtime for hosting a custom web application. It is tempting because it also removes hardware and hypervisor management, but it is designed for delivering user desktops, not application workloads.
Go deeper
Related to this question
Learn chapter
Mobile Operating Systems: iOS and Android
Key term
Anything As A Service
A model where you rent any IT resource or service over the internet instead of owning it.
Key term
Operating system
An operating system (OS) is the core software that manages a computer's hardware and software resources, providing common services for computer programs.
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Same concept, more angles
2 more ways this is tested on 220-1101
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 wants to migrate a custom-developed web application to the cloud. The IT team needs full control over the operating system, middleware, and runtime environment but does not want to manage physical hardware or the underlying virtualization layer. Which cloud service model should the organization choose?
medium- A.Software as a Service (SaaS)
- B.Platform as a Service (PaaS)
- ✓ C.Infrastructure as a Service (IaaS)
- D.Desktop as a Service (DaaS)
Why C: Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet, giving the customer full control over the operating system, middleware, and runtime environment while abstracting away the physical hardware and underlying virtualization layer. This matches the requirement for complete control without managing the physical infrastructure.
Variation 2. A company wants to migrate its custom web application to the cloud. The development team needs full administrative access to the operating system, the ability to install custom middleware, and control over security configurations. They want to avoid managing the physical servers, hypervisors, and data center infrastructure. Which cloud service model should the company choose?
medium- ✓ A.Infrastructure as a Service (IaaS)
- B.Platform as a Service (PaaS)
- C.Software as a Service (SaaS)
- D.Desktop as a Service (DaaS)
Why A: Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet, giving the development team full administrative access to the operating system, the ability to install custom middleware, and control over security configurations. The cloud provider manages the physical servers, hypervisors, and data center infrastructure, while the customer retains control over the OS, storage, and deployed applications. This matches the requirement for full OS-level access without managing the underlying hardware.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 practice question is part of Courseiva's free CompTIA 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 220-1101 exam.