Gateway Timeouts on scaled out Azure App Services?

Urs Enzler 41 Reputation points

Our scenario: We have a simple client-server architecture where a PWA is using our Azure Web Service (Windows hosted) as the backend. The backend has scaling out enabled (min 2 instances). We have this setup for years and it worked well.

However, for about 1-2 weeks, the client has been receiving Gateway Timeouts from our backend. Although we cannot say this with absolute certainty, Gateway Timeouts seem to occur when a call to the backend is being made while an app service instance is shut down.

For us, it looks like the standard load balancer in front of our app service instances redirects the call to an already shut-down instance. This is a behavior we didn't see in the last years.

Can someone confirm this behavior and/or our hypothesis? And is there a way to avoid this?

Azure App Service
Azure App Service
Azure App Service is a service used to create and deploy scalable, mission-critical web apps.
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