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Tayyab Suhail's avatar
Tayyab Suhail
Copper Contributor
Apr 21, 2020
Solved

Azure Application Gateway with App Service

Hi Community,   Can someone help me in understanding that how scalability  is handled by APG on app service level. Let's take an example, we have an app service deployed and running with auto-scale...
App Services
application gateway
virtual network
  • hspinto's avatar
    hspinto
    Apr 21, 2020

    Tayyab Suhail, when you configure App Service as a backend for AppGW, you are providing its URL, not the actual references to the App Service Plan instances. AppGW only knows a Web App URL, as much as any other HTTP client. Therefore, App Service scaling operations are transparent to AppGW, no matter you have 1 or 10 instances.

hspinto's avatar
hspinto
Icon for Microsoft rankMicrosoft
Apr 21, 2020

Tayyab Suhail, Azure App Service honors ARRAffinity, so, even with AppGW in front of it, App Service "load balancer" should keep sending session-affinity-based requests to the same backend instance. However, take into account that App Service may be responding to requests with a different "Location" header, which will break session affinity. Read this article for a description of the problem and possible solutions.

Tayyab Suhail's avatar
Tayyab Suhail
Copper Contributor
Apr 21, 2020
Thank you very much hspinto, i will go through this link and get back to you in case of any questions. Appreciate your help!