1.3.4. 💡 First Principle: Azure Service Types (IaaS, PaaS, SaaS)
First Principle: Azure offers three fundamental service types (IaaS, PaaS, SaaS), each abstracting different levels of infrastructure management. Understanding these types is crucial for choosing the most appropriate model to balance control, development speed, and operational overhead.
What It Is: "IaaS, PaaS, and SaaS" are the main categories of cloud computing services, defining the level of control and responsibility shared between the cloud provider (Microsoft) and the customer.
Visual: "Cloud Service Models" (IaaS, PaaS, SaaS)
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Key Service Types:
| Service Type | Description | Example Azure Services | Example Use Case |
|---|---|---|---|
| "IaaS" | "Infrastructure as a Service": Provides fundamental computing resources (virtual machines, networking, storage). You manage the OS, applications, and data. Microsoft manages virtualization, servers, storage, and networking hardware. | Azure Virtual Machines (VMs), Azure Virtual Network (VNet), Azure Storage (Disks). | Full control over OS and runtime (e.g., migrating legacy apps, hosting custom software that requires specific OS configurations). |
| "PaaS" | "Platform as a Service": Provides a managed environment for app development and deployment. Azure manages the OS, runtime, and middleware. You manage your application code and data. | Azure App Service, Azure Functions, Azure SQL Database, Azure Cosmos DB. | Deploying web apps, APIs, or serverless functions without managing servers; using managed databases. |
| "SaaS" | "Software as a Service": Ready-to-use applications delivered over the internet, managed entirely by the provider. You only use the software. | Microsoft 365, Dynamics 365, Azure DevOps. | Productivity tools, CRM, project management software delivered as a service. |
Scenario: You need to migrate a legacy application that requires a very specific operating system configuration and custom drivers. Separately, you want to build a new web API that needs to scale automatically without you managing servers.
Reflection Question: How does understanding the different levels of abstraction in Azure service types (IaaS, PaaS, SaaS) fundamentally guide your choice of compute and database solutions, balancing control, development speed, and operational overhead for diverse application needs?