Under the App Service hosting plan, the auto-scaling is available, although it is not as dynamic. As will be discussed in Chapter 13, Designing Cost Effective Services, the App Service allocates dedicated VMs to your App Service when you are running in the Basic, Standard, or Premium tier.
The App Service plan is good for long running functions, as there is no limit on the function execution time. It is also good for functions that require fast start-up time after a period of inactivity, since the App Service plan has at least one dedicated instance always allocated to the Function App. You can also enable the Always On setting on the App Service to prevent the instance from going idle.
App Service plan is also required for ...
