How Scale-out Works in Azure App Services

Question

I am trying to disguise the concept of Azure App Service and Azure App Services with no luck.

I understand that the application service plan determines the capacity and price, all applications assigned to a specific App Service plan will use the same resources, right?

If this is correct, then what is the advantage of scaling? If the scale will create more instances of the same application, which at the end will be placed on the same application service plan (sharing the same resources)?

I read almost all the official and unofficial documentation about Azure App Service and App Services plans, but could not find an answer to this question, they all say that scaling works at the application level (and not at the plan application service) and at the same time stating that the applications assigned to the same application service plan actually use the same resources, so what are the benefits of the scaling feature?

Hi,

Answer 1

My understanding is that the Application Service Plan defines the capabilities and pricing, all applications assigned to a particular application service plan will share the same resources, right?

Yes.

If this is correct, then what is the advantage of scaling? If the scale will create more instances of the same application, which at the end will be placed on the same application service plan (resources)?

No one forces you to put all your applications in the same application maintenance plan. When you create an application, you put it in some kind of application maintenance plan. All applications on this (and only that) application plan will share resources, but you can create many Application Service Plans.
In addition, when you zoom out, you create more PaaS instances of the virtual machine hosting your application, so when you scale, you do not get another application pool in the same IIS, you get another application pool on another IIS on another virtual the car.

edit: to clarify the comment, the Application Service Plan is a collection of Windows virtual machines with IIS installed on them. All applications assigned to this Application Services Plan are hosted in ALL copies of these virtual machines, when you scale or zoom in, you change the number or capacity of these virtual machines.
There is no temporary application maintenance plan. You pay for the service plan, not the application. Applications cost nothing , they just consume resources in terms of service, its service plan, which "eats" money. You receive an invoice according to the level and scope of the service plan .
Pricing is based on the size and number of VM instances you run.

Answer 2

As I know, scale will create multiple copies of your web application and add load balancing to automatically distribute requests between them. And you do not need to adjust the load balance separately.

Assuming that you are creating a website (a Windows server with IIS), your website will have an application pool that defines the available resources for your website. Each instance can handle a limited number of requests in order to reduce response time, you could scale your website in several instances, then each web server could share the workload. For more information, you can refer to Scaling and Scaling on Windows Azure Websites and a tutorial for a better understanding of Azure Web App auto-scale.

Answer 3

As @ 4c74356b41 said that when scaling, you will get more physical resources (for example, a VM with a lot of computing, memory and storage). In addition, one scalable Azure documentation adjustment will affect all applications in terms of application service. see the link below, and also note that

“The scale settings take only a few seconds to apply and affect all applications in your App Service plan. They do not require code changes or redeployment of your application” - https://azure.microsoft.com/en-us/documentation/articles/ web-sites-scale /