Why is a Microsoft.Web/serverfarms resource required for hosting a website?

Question

I'm tutoring myself on Azure Resource Manager and Azure Resource Group template files. I'm using the Azure SDK v2.6. I'm intrigued to know why, when I pick a WebSite template, it contains a Microsoft.Web/serverFarms resource. Given that Azure Web Sites is a PaaS offering why do I need to care about the notion of a server farm?

Just interested to know that's all.

Answer 1

That's just the resource provider name for the Web Hosting Plan, now called App Service Plan.

Answer 2

The App Service plan defines the virtual machines that run the Web Site.

You can have a number of applications running within an App Service Plan, Web apps, Logic apps, API apps. Every app running will take a share of the performance that is available to the Service Plan.

You can consider the Web Site to be a single site under IIS, before you can deploy a site to IIS you need a server to host IIS on. That is what the App Service plan / serverfarm provides.