Explain Shared Responsibility models

Question

Explain me the difference between Infrastruature as a service,Platform as a service, and Software as a Service.Like what has controll over things?

This question is related to the following Learning Module

Answer 1

The differences between Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) revolve around the level of control and responsibility the user has over the IT infrastructure and application stack. Here's a detailed explanation of each model:

Infrastructure as a Service (IaaS)

Description:

• IaaS provides virtualized computing resources over the internet.
• It allows users to rent virtual machines (VMs), storage, networks, and other fundamental computing resources.

Control:

• Users have control over the operating systems, storage, deployed applications, and often network configurations.
• Users are responsible for managing and maintaining the operating system, middleware, runtime, data, and applications.

Azure Example Services:

• Azure Virtual Machines
• Azure VNet (Virtual Network)
• Azure Storage
• Azure Load Balancer

Responsibility:

• User: Application, Data, Runtime, Middleware, OS
• Provider: Virtualization, Servers, Storage, Networking

Platform as a Service (PaaS)

Description:

• PaaS provides a platform allowing customers to develop, run, and manage applications without dealing with the infrastructure.
• It includes middleware, development tools, database management systems, business analytics, and more.

Control:

• Users have control over the applications and data.
• The underlying infrastructure, operating systems, and middleware are managed by the service provider.

Azure Example Services:

• Azure App Services (Web Apps, Mobile Apps, API Apps)
• Azure SQL Database
• Azure Logic Apps
• Azure Functions

Responsibility:

• User: Application, Data
• Provider: Runtime, Middleware, OS, Virtualization, Servers, Storage, Networking

Software as a Service (SaaS)

Description:

• SaaS delivers software applications over the internet, on a subscription basis.
• It is a complete software solution that you purchase on a pay-as-you-go basis from a cloud service provider.

Control:

• Users have limited control, typically confined to configuration settings within the application.
• The underlying infrastructure, operating systems, middleware, and application software are managed by the service provider.

Azure Example Services:

• Microsoft 365 (Office 365)
• Dynamics 365
• Azure DevOps
• Azure Active Directory

Responsibility:

• User: Data (sometimes configuration settings)
• Provider: Application, Runtime, Middleware, OS, Virtualization, Servers, Storage, Networking

Summary Table of Responsibilities

Responsibility	SaaS	PaaS	IaaS
Applications	Provider	User	User
Applications	Provider	User	User
Data	User	User	User
Runtime	Provider	Provider	User
Middleware	Provider	Provider	User
OS	Provider	Provider	User
Virtualization	Provider	Provider	Provider
Servers	Provider	Provider	Provider
Storage	Provider	Provider	Provider
Networking	Provider	Provider	Provider

Key Points:

• IaaS provides the most flexibility and control but requires more management from the user.
• PaaS offers a balance by providing managed infrastructure and middleware, allowing users to focus on application development.
• SaaS provides the least amount of control but the most ease of use, as everything is managed by the service provider.

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hth

Marcin