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AZ-900 starter: the three cloud service types

A short course on IaaS, PaaS and SaaS for the Azure Fundamentals exam: who manages what, and which type fits which situation.

Written by DataStudyGuides test account. Not reviewed by DataStudyGuides.

Microsoft · AZ-900 · Microsoft Azure Fundamentals · 3 cards · 9 questions

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Cloud service types

Infrastructure as a service

IaaS rents you the hardware in a cloud datacenter: the most control, and the most to manage yourself.

  1. YouApplications and data
  2. YouOperating system, patching, configuration
  3. YouNetwork, database and storage configuration
  4. ProviderHardware, internet connectivity, physical security
Who manages what in IaaS

Infrastructure as a service (IaaS) is the most flexible cloud service type. You rent the hardware in a cloud datacenter, and what you do with it is up to you. The provider keeps the hardware running, connected and physically secure. Everything above that is yours.

Pick IaaS to move an existing server to the cloud as it is (lift and shift), or to start and stop test environments quickly while keeping full control.

On the exam, full control of the operating system points to IaaS.

Key points

  • Provider: hardware, network connectivity to the internet, physical security
  • You: operating system, network configuration, database and storage configuration
  • Control: the most flexible of the three service types
  • Good fit: lift-and-shift migration, test and development environments

Exam trap

Most control also means most responsibility: with IaaS you still install, patch and maintain the operating system yourself.

Platform as a service

PaaS gives you a managed platform to build on: the provider also runs the operating system, middleware and development tools.

  1. YouApplication code, data, access controls
  2. ProviderOperating systems, middleware, development tools
  3. ProviderHardware, internet connectivity, physical security
Who manages what in PaaS

Platform as a service (PaaS) sits between renting hardware (IaaS) and using a finished application (SaaS). The provider maintains the physical infrastructure and also the operating systems, middleware and development tools. You do not have to license or patch operating systems and databases.

Pick PaaS when a team wants a complete environment to develop and run an application without maintaining the infrastructure under it.

On the exam, focus on the application, not on servers points to PaaS.

Key points

  • Provider: infrastructure plus operating systems, middleware, development tools
  • You: your application code, your data and access controls
  • No patching: operating systems and databases are licensed and patched for you
  • Good fit: a development framework, analytics or business intelligence

Exam trap

PaaS is the middle ground. You no longer patch the operating system, but you are still responsible for your own application and data.

Software as a service

SaaS is a finished application that you rent: the least to manage and the least flexibility.

  • You need full control of the operating systemIaaS
  • You want to build an application without managing serversPaaS
  • You want a finished application to use right awaySaaS
Which service type fits

Software as a service (SaaS) is the most complete service type: you rent or use a fully developed application. The provider manages the infrastructure, the platform and the application. You manage your data, who may sign in, and which devices connect.

It is the least flexible type and the easiest to start with.

On the exam, a ready-made application such as email points to SaaS.

Key points

  • Provider: almost the whole stack, including the application itself
  • You: your data, identity and access settings, the devices that connect
  • Easiest: needs the least technical knowledge to start using
  • Examples: email, messaging, productivity and finance applications

Exam trap

Least to manage does not mean nothing to manage: with SaaS you still decide who gets access and you remain responsible for your data.