Cloud Service Models Explained

The Pizza Analogy

The three cloud service models are easiest to understand through a simple analogy: pizza.

Make it yourself (On-premise): You buy ingredients, make the dough, build a brick oven, and cook everything from scratch. Maximum control, maximum effort.

IaaS (Infrastructure as a Service): You rent a commercial kitchen. The oven, countertop, and refrigerator are provided. You bring your own ingredients and recipes. You control what you cook and how — but you don’t maintain the building.

PaaS (Platform as a Service): You use a meal kit delivery service. The ingredients arrive pre-measured, the recipe is provided, and you just cook. You focus on the cooking (your code), not the shopping or kitchen setup.

SaaS (Software as a Service): You order delivery. The pizza arrives ready to eat. You didn’t cook, didn’t shop, didn’t maintain any equipment. You just eat.

Each model trades control for convenience. More control means more responsibility. More convenience means less customization.

The Three Models in Detail

IaaS: Infrastructure as a Service

What you get: Virtual machines, storage, and networking — the building blocks of computing.

What you manage: Operating system, applications, data, runtime, middleware.

What the provider manages: Physical hardware, virtualization, data center.

Real examples: AWS EC2, Azure Virtual Machines, Google Compute Engine

Explain this cloud computing concept to me like I'm
a non-technical professional:

I have a virtual machine on AWS EC2. Help me understand:
1. What is this actually giving me?
2. What do I need to manage myself?
3. What does AWS handle for me?
4. When would this be the right choice vs. simpler options?

Use a real-world analogy to make it clear.

Best for: Teams that need full control — specific OS versions, custom software stacks, GPU computing, or regulatory requirements that demand configuration control.

PaaS: Platform as a Service

What you get: A complete development and deployment environment.

What you manage: Your application code and data.

What the provider manages: Everything else — servers, OS, runtime, scaling, patches.

Real examples: Heroku, Google App Engine, AWS Elastic Beanstalk, Azure App Service

Best for: Developers who want to ship code fast without managing infrastructure. Startups, small teams, and anyone who’d rather write features than configure servers.

SaaS: Software as a Service

What you get: Complete, ready-to-use applications.

What you manage: Your data and settings.

What the provider manages: Everything — infrastructure, platform, application, updates, security.

Real examples: Gmail, Slack, Salesforce, Zoom, Dropbox, Microsoft 365

Best for: End users who need software tools without technical overhead. This is what most non-technical professionals mean when they “use the cloud.”

✅ Quick Check: If you use Google Docs to write a document, which cloud service model are you using? SaaS. Google manages the servers, the application code, the updates, and the security. You just open a browser and type. Over 53% of all cloud revenue comes from SaaS — it’s the most common way people interact with cloud computing.

The Shared Responsibility Model

Each service model shifts the dividing line between what you manage and what the provider manages:

Component	On-Premise	IaaS	PaaS	SaaS
Data	You	You	You	You
Applications	You	You	You	Provider
Runtime	You	You	Provider	Provider
Operating System	You	You	Provider	Provider
Networking	You	Provider	Provider	Provider
Storage	You	Provider	Provider	Provider
Servers	You	Provider	Provider	Provider
Data Center	You	Provider	Provider	Provider

Notice that you always manage your data regardless of the model. This is critical for security and compliance — even if the provider manages everything else, your data is your responsibility.

✅ Quick Check: In the shared responsibility model, who is responsible for data security in all three service models? You are. Even in SaaS, where the provider manages the entire application and infrastructure, data security remains a shared responsibility. You need to manage access controls, user permissions, and data classification. The provider secures the platform; you secure what you put on it.

Deployment Models

Beyond service models, cloud computing has four deployment approaches:

Model	What It Means	Best For
Public Cloud	Resources shared across many customers (AWS, Azure, GCP)	Most workloads — cost-effective, scalable
Private Cloud	Dedicated infrastructure for one organization	Regulated industries (healthcare, finance, government)
Hybrid Cloud	Mix of public and private cloud	Organizations transitioning to cloud or with mixed requirements
Multi-Cloud	Using multiple public cloud providers	Avoiding vendor lock-in, leveraging best-of-breed services

Public cloud holds 55.88% of the market because it offers the best cost-to-flexibility ratio for most workloads.

Key Takeaways

The three cloud service models (IaaS, PaaS, SaaS) trade control for convenience — IaaS gives maximum control with maximum responsibility, SaaS gives maximum convenience with minimum customization
IaaS provides virtual infrastructure (servers, storage, networking) for teams needing full control over their computing environment
PaaS provides a development platform so developers can focus on code without managing servers, OS patches, or scaling
SaaS provides ready-to-use applications (Gmail, Slack, Salesforce) that 53% of cloud revenue comes from — it’s the model most people use daily
You always manage your own data regardless of the model — even in SaaS, access controls and data security are your responsibility

Up Next: You’ll compare AWS, Azure, and Google Cloud — the three major platforms that dominate 67% of the cloud market — to understand their strengths, pricing approaches, and which one to start learning first.