Cloud Service Models

The "Shared Responsibility Model". Moving to the cloud is about trade-offs: How much control do you want to keep vs. how much work do you want to offload?

IaaS

Infrastructure as a Service. You rent the raw hardware (Virtual Machines). You install the OS, patch it, and run your app. Maximum flexibility, maximum work.

Ex: AWS EC2, Google Compute Engine

PaaS

Platform as a Service. You bring the code; they run it. They handle the OS, patching, and scaling. You just focus on the app logic.

Ex: AWS Lambda, Heroku, Google App Engine

SaaS

Software as a Service. You just use the software. You don't care about servers, code, or updates. It just works in your browser.

Ex: Gmail, Dropbox, Salesforce

🍕 The "Pizza as a Service" Analogy

🏠

On-Premises

Made at Home.
You buy dough, cheese, oven, gas, and soda. You cook and clean.

🛒

IaaS

Take-and-Bake.
You buy a pre-made pizza (VM), but you still need your own oven (OS) to cook it.

🛵

PaaS

Pizza Delivery.
They cook it and bring it to your door. You just need a table (Data) to eat.

🍽️

SaaS

Dining Out.
You go to a restaurant. They do everything. You just show up and eat.

🕹️ Responsibility Simulator

Visualizing the Stack: Click the buttons to see which layers turn Green (Provider Managed) vs Blue (You Managed).

On-Premises: You own the data center. You replace failed hard drives. You patch the OS. You are responsible for everything from the concrete floor up to the application code.

You Manage

Provider Manages

Data & Access

Applications

Runtime

Middleware

Operating System

Virtualization

Servers

Storage

Networking