A user recently submitted the following question. What is the correct answer?"A quiz question in the CCSK self-paced course specifically asks which of the 5 boxes below are used to help build SaaS on top of IaaS and points you (when you hit the Review Question button) to the architecture description below as to where the answer should be. Personally I found the description to be fairly jumbled and non specific, so it's not clear (to me at least) what the specific answer is. All the boxes/options in the question except Notification services, are listed as components of IaaS and PaaS in the description, none are explicitly described as SaaS components.
Listed as PaaS in the description
Listed as IaaS in the description
So it's not clear what is eliminated and what is included so the answer is not clear."
In principle and in most cloud environments, you wouldn't be able to build a functional SaaS application without any of the 5 components listed in the question (in the screenshot). They are all important and you would use all of them.To answer that question, you need to look at the Cloud Reference Architecture Model in the Guidance document (Guidance v4, page 13). You want to select the SaaS components that are built on IaaS and can be mapped to the SaaS section of that Model.The guidance defines Relational Databases as PaaS components and Notification Services as PaaS features (but you could argue these 2 can also be IaaS components). Although they are essential in building a functional SaaS application , they are not SaaS components in the Model.The Web Server Auto Scale Group, the Application Server Auto Scale Group, and the Container Cluster are components you use to present your SaaS application to your SaaS users, and run and execute your SaaS application code in your IaaS environment. They are the SaaS components that you build on IaaS and can be mapped to the SaaS section of the Cloud Reference Architecture Model.