Is there a way to know which backend is serving the traffic?

Question

We have 3 backend linux servers where nodejs application is installed. Azure application gateway is configured to route the requests to these 3 backend nodes. However, we would like to setup a custom header in Application Gateway to understand at any point in time which backend is currently serving the traffic? Is there a way to achieve this in Application Gateway?

Answer 1

Hello,

Welcome to Microsoft Q&A,

To configure Azure Application Gateway to add a custom header to responses, you can utilize its header rewrite capability. This feature allows you to insert, remove, or modify HTTP headers in both request and response messages.

https://learn.microsoft.com/en-us/azure/application-gateway/rewrite-http-headers-portal

You can create and set the custom header "X-Backend-Server". If you want to dynamically insert the backend server's IP address or hostname, you can use server variables like {server_name} or {server_ip}.

After defining the rule, associate the rewrite set with the appropriate listener or routing rule.

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