IaaS, PaaS, SaaS

IaaS = Infrastructure as a Service

Typically provides a HW (+ OS) platform for its users (eg I need a 2 CPU CentOS7 machine with 2G memory)

• Scope: Infrastructure (virtual machines and images, storage, network elements)
• Advantages: unified / standard virtualization on strong host machines; rapid machine demand handling and creation (even runtime scaling)
• Target group: operators, DevOps
• Examples: Amazon EC2, Rackspace, Google Compute Engine, OpenStack. At this lab, the IaaS solution is provided by OpenStack!

PaaS = Platform as a Service

Typically, application servers, middleware, application runtime environment for users (eg I need a JBoss JEE server or a NodeJs running environment)

• Scope: Application Runtime Environments (middleware, application platforms)
• Advantages: uniform / standard application development and deployment environment; rapid platform request and creation (even runtime scaling)
• Target group: application developers
• Examples: OpenShift, Heroku, Google App Engine. At this lab, the PaaS solution is provided by OpenShift!

SaaS = Software as a Service

Typical ready-to-use applications for their users (eg I need a mail system, CRM application, Webshop, etc.)

• Scope: Applications, services
• Advantages: I have an immediately available, usable service; no development costs; instead of a one-time investment, regular pay
• Target group: end users
• Examples: Office Cloud, Google Apps (Forms, Calendar, …)

Maturity levels of cloud technologies

https://container-solutions.com/cloud-native-maturity-matrix/