> For the complete documentation index, see [llms.txt](https://docs.arkannis.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arkannis.net/cloud/azure/courses/az900-course/cloud-models-and-cloud-types/iaas-paas-saas.md).

# IaaS, PaaS, SaaS

## "Something" as a Service

* The idea is that you don't own that thing
* Someone lese owns it and you benefit from it - "as a service"
* You're not in control of how it's delivered (for the most part)
* Pay as you go; no upfront costs

**Example**: Cooking at home --> Cooking as a Service (Restaurant) Driving your own car --> Driving as a Service (Taxi)

## Software as a Service (SaaS)

* You `don't control` the servers (or even know what they are)
* You `don't control` the software (or even know what version number is running)
* You `control` the data and settings only

**It stands alone as a useful product; does not require something else to be useful**

**Example**: Microsoft Office 365 - SaaS Sharepoint, Outlook, Word, Excel, etc...

## Platform as a Service (PaaS)

* You `don't control` the servers (but you might be able to pay more for performance)
* You `control` the data and settings
* Often it's programmable and you can upload your own code
* Provides useful features above the raw storage or compute underneath

**It's a platform that you need to build upon to be useful**

**Example**: App Service - PaaS Azure SQL Database - PaaS

## Infrastructure as a Service (IaaS)

* You `do control` the VM
* It's a virtual imitation of a real piece of a network
* Falls into 3 categories:
  * Compute
  * Networking
  * Storage

**Completely "dumb" unless you control it**

**Example**: Virtual Machines - IaaS Azure Storage - IaaS Load Balancer - IaaS

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