Unit 3 of 3
Cloud Service Types (IaaS, PaaS, SaaS)
Learning objectives
When you finish this unit, you will be able to:
- Describe infrastructure as a service (IaaS).
- Describe platform as a service (PaaS).
- Describe software as a service (SaaS).
- Identify appropriate use cases for each cloud service (IaaS, PaaS, SaaS).
Cloud service models
Each service model defines a different level of control and responsibility for the customer.
Infrastructure as a Service (IaaS)
Provides virtualized compute, storage, and networking. You manage the OS, middleware, and applications. Example: Azure Virtual Machines.
Platform as a Service (PaaS)
Provides a managed platform for developing, running, and managing applications without managing underlying infrastructure. Example: Azure App Service.
Software as a Service (SaaS)
Delivers fully managed applications over the internet. The provider manages everything from infrastructure to the application itself. Example: Microsoft 365.
Choosing the right model
Match the service type to the scenario:
- Need full control over the OS? → IaaS
- Want to deploy code without managing servers? → PaaS
- Need a ready-to-use application? → SaaS
Exam focus: identify which service model fits a given use case and understand the shared responsibility shift across IaaS, PaaS, and SaaS.