In this post we will talk about App Service Plan that exists for Azure App Service. The main scope of this post is not to cover all the details, but to put on the table the small things that can make a difference. Do we have a service plan for Web/Worker Roles? No, App Service Plan exists only for Azure App Services like Web Apps, API Apps, Logical Apps, Mobile Apps and so on. Why when I increase the number of instances of a specific Web App I increase automatically the size of the rest of the Web Apps from the same service plan? All resources are shared between all the applications from the same App Service Plan. This means that when you increase the number of instances, you will see this change on all Apps from the same App Service Plan. When I use the same App Service Plan does multiple apps share the same physical resources? Yes. All Azure Apps under the same App Service Plan are using the same resources. For example if you have 3 Web Apps under the same App Service Plan, all of them will use and shared the resources. In the above example we have 5 Web Apps that are running under the same App Service Plan. This plan has one instance of a Standard 2 (S2) machine. This means that all our Web App (all 5) are running on the same physical machine S2. Can I have the same App Service Plan across multiple datacenters (regions)? No, you can't. Each App Service Plan is for a specific datacenter. This is normal in the context of sharing the physical resources between different applications (apps). Can I optimize costs? Yes, using App Service Plan you can share the same resource between different apps. This means that you can allocate the same resource for app with a small load. When I should use a dedicated App Service Plan for one App? This should be done when you want to have dedicated resources for this app. For example if you have an App that is hitted by many clients or when you need to offer the same quality attributes (response time for example) regardless on what is happening on another sub-systems. Can I move an App from one App Service Plan to another? Yes. You can move in any moment an App from one service plan to another.
