Microsoft SaaS, IaaS, and PaaS concepts and use cases
5 minutes
5 Questions
Microsoft offers three primary cloud service models through Azure and Microsoft 365: Software as a Service (SaaS), Infrastructure as a Service (IaaS), and Platform as a Service (PaaS). Each model provides different levels of control and management responsibilities.
SaaS (Software as a Service) del…Microsoft offers three primary cloud service models through Azure and Microsoft 365: Software as a Service (SaaS), Infrastructure as a Service (IaaS), and Platform as a Service (PaaS). Each model provides different levels of control and management responsibilities.
SaaS (Software as a Service) delivers complete applications over the internet. Users access software through a web browser, and Microsoft handles all infrastructure, maintenance, and updates. Microsoft 365 is a prime example, offering applications like Outlook, Teams, SharePoint, and OneDrive. Organizations pay subscription fees and receive ready-to-use productivity tools. SaaS is ideal for email solutions, collaboration platforms, and customer relationship management systems.
IaaS (Infrastructure as a Service) provides virtualized computing resources over the cloud. Microsoft Azure offers virtual machines, storage, and networking components. Organizations rent these resources and maintain control over operating systems, applications, and data. Azure Virtual Machines exemplify this model. IaaS suits scenarios requiring custom server configurations, development and testing environments, and migrating existing workloads to the cloud. Organizations handle patching and security while Microsoft manages physical hardware.
PaaS (Platform as a Service) offers a development and deployment environment in the cloud. Azure App Service and Azure SQL Database represent PaaS offerings. Developers focus on building applications while Microsoft manages the underlying infrastructure, operating systems, and runtime environments. PaaS accelerates application development, supports web and mobile app hosting, and provides database management solutions.
The shared responsibility model varies across these services. With SaaS, Microsoft assumes most management tasks. IaaS places more responsibility on customers for configuration and maintenance. PaaS falls between, allowing developers to concentrate on code while the platform handles infrastructure concerns.
Organizations often combine these models to create comprehensive cloud solutions that balance control, flexibility, and operational efficiency based on their specific business requirements and technical capabilities.
Microsoft SaaS, IaaS, and PaaS Concepts and Use Cases
Why This Is Important
Understanding the three main cloud service models—Software as a Service (SaaS), Infrastructure as a Service (IaaS), and Platform as a Service (PaaS)—is fundamental to the MS-900 exam. These concepts form the foundation of how Microsoft 365 and Azure services are delivered and consumed by organizations worldwide.
What Are SaaS, IaaS, and PaaS?
Software as a Service (SaaS) SaaS provides complete applications over the internet. Users access software through a web browser, and the provider manages everything from infrastructure to application updates. Microsoft 365 apps like Outlook, Teams, and SharePoint Online are prime examples of SaaS.
Infrastructure as a Service (IaaS) IaaS provides virtualized computing resources over the internet. You rent IT infrastructure—servers, virtual machines, storage, and networks—from a cloud provider. Azure Virtual Machines and Azure Storage are examples of IaaS. You manage the operating system, middleware, and applications.
Platform as a Service (PaaS) PaaS provides a platform for developers to build, deploy, and manage applications. The provider manages the underlying infrastructure while you focus on development. Azure App Service and Azure SQL Database are examples of PaaS.
How It Works - The Shared Responsibility Model
Each service model has different levels of management responsibility:
• SaaS: Microsoft manages almost everything. You manage user access, data, and device configuration. • PaaS: Microsoft manages infrastructure and platform. You manage applications and data. • IaaS: Microsoft manages physical hardware and virtualization. You manage OS, applications, data, and security configurations.
Common Use Cases
SaaS Use Cases: • Email and collaboration (Microsoft 365) • Customer relationship management • Enterprise resource planning
IaaS Use Cases: • Migrating existing on-premises workloads to the cloud • Development and testing environments • High-performance computing • Disaster recovery solutions
PaaS Use Cases: • Building custom web applications • Database management • Business analytics and intelligence • API development and management
Exam Tips: Answering Questions on Microsoft SaaS, IaaS, and PaaS
1. Remember the responsibility levels: When a question asks about who manages what, recall that SaaS has the least customer responsibility, IaaS has the most, and PaaS falls in between.
2. Focus on flexibility vs. convenience: IaaS offers the most control and flexibility, while SaaS offers the most convenience with the least management overhead.
3. Match scenarios to service models: If a question describes a company wanting to run legacy applications with full OS control, think IaaS. If they want to develop custom apps with managed infrastructure, think PaaS. If they need ready-to-use productivity tools, think SaaS.
4. Know Microsoft examples: Be familiar with which Microsoft products fall into each category—Microsoft 365 is SaaS, Azure VMs are IaaS, Azure App Service is PaaS.
5. Consider cost implications: SaaS typically uses subscription-based pricing, IaaS uses pay-as-you-go for resources consumed, and PaaS charges based on platform usage.
6. Think about scalability: All three models offer scalability, but the implementation differs. Understand that cloud services allow organizations to scale resources based on demand.