A lot Concurrent requests on Application Gateway and Function App

Question

Hi

We have an application gateway with HTTPS listener (with entries for the public IP in the domain provider). The Application Gateway has a private function App in the back-end. The domain of the application gateway is same as the domain of an another function app that is unrelated to application gateway. But there is no A record for that in the public domain provider and the function app itself is private with entries in the Internal DNS servers (there are no private DNS zones).

We just realized that there were thousands of request on the Function App with x-forwarded-for ip as the Application Gateway subnet's IP. And the client IP were random IPs on the internet (some of them were IPv6 as well from random locations like Sweden, India etc). The url in the requests was

Answer 1

Hi @Rajat Srivastava , I understand you want to know what requests come to /warmup/admin path of your Function App hosted on App Service Plan.

It's warmup trigger. A warmup trigger is invoked when an instance is added to scale a running function app. The warmup trigger is only called during scale-out operations, not during restarts or other nonscaling startups.

As it's called during scale-out operations, it should not be in the thousand's magnitude, unless your function app scales that much.