📘 07-01: Cloud Service Models¶
📌 The Three Core Models¶
Cloud services differ by how much the provider manages vs. you.
| Model | Provider manages | You manage | Example |
|---|---|---|---|
| IaaS | Hardware, virtualization, network | OS, apps, data | AWS EC2, Azure VMs |
| PaaS | + OS, runtime, middleware | Just your code/data | Azure App Service, Heroku |
| SaaS | Everything | Just your usage/config | Microsoft 365, Salesforce |
More letters "as-a-Service" you offload upward = less you manage. IaaS = most control; SaaS = least effort.
📌 The "Pizza as a Service" Analogy¶
- IaaS — they give you the kitchen; you cook.
- PaaS — they give you the oven and dough; you add toppings.
- SaaS — pizza delivered, ready to eat.
📌 Other "as-a-Service" Terms¶
| Term | Delivers |
|---|---|
| DaaS | Virtual desktops (VDI in the cloud) |
| DBaaS | Managed databases |
| XaaS | "Anything" as a service |
📌 Shared Responsibility¶
The provider secures the layers they manage; you secure your OS/apps/data/access according to the model. Responsibility shifts more to the provider as you move IaaS → PaaS → SaaS.
Tip
Key idea — IaaS = VMs/infra, PaaS = dev platform, SaaS = finished apps. The higher the service, the less you manage — but you always secure your data and access.
See also: Cloud Deployment Models & Characteristics, Virtualization
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