Cloud Fundamentals
/Intermediate
IaaS vs PaaS vs SaaS
Definition
The three primary service models of cloud computing, representing different levels of management responsibility. Infrastructure (IaaS), Platform (PaaS), and Software (SaaS) as a Service.
Explain Like I'm New
The Pizza Analogy. IaaS: Buying dough, cheese, and an oven, but baking it yourself. PaaS: Getting a frozen pizza delivered and just baking it. SaaS: Going to a restaurant and having the pizza handed to you fully cooked.
Real World Example
IaaS: AWS EC2 (Raw virtual server, you install the OS). PaaS: Heroku or AWS Elastic Beanstalk (You just upload your code, they handle the servers). SaaS: Gmail or Salesforce (You just log in and use the app).
Common Use Cases
- •Choosing architectures
- •Budgeting IT resources
Cloud Service Models Comparison
| Model | You Manage | Cloud Provider Manages | Analogy |
|---|---|---|---|
| On-Premises | Everything (Networking, Storage, Servers, OS, App) | Nothing | Building a car from scratch in your garage. |
| IaaS (Infrastructure) | OS, Runtime, Data, App | Networking, Storage, Servers, Virtualization | Leasing a car. You drive it and put gas in it. |
| PaaS (Platform) | Data, App | Everything else (OS, servers, runtime) | Taking a taxi. You just tell them where to go. |
| SaaS (Software) | Nothing (Just configuration) | Everything | Riding a bus. Pre-set route, you just sit down. |
Interview Questions
basic
- Is Google Docs an example of IaaS, PaaS, or SaaS?
intermediate
- If you use a PaaS, do you need to worry about installing monthly Linux security patches on the underlying servers?