Azure Load Balancer to Check if HTTP Response Has No Status Code

Question

Hi, is it possible for Azure Load Balancer to check if an HTTP response does not have a status code?

We have an application that is deployed in two Azure VMs (let's call it VM1 and VM2) using IIS. An Azure Load Balancer is created to route requests to one of these two. There is also an automated process created in them which restarts the application pools at a specified time of the day.

Recently we encountered a problem wherein an HTTP request was sent to VM1 while the automated process was running. Since our application was in an unresponsive state during this time it returned an HTTP response of Canceled. Because the VM itself is up and running, the load balancer assumed that it can route the requests there.

Is there a way for us to solve this problem? Can we force the load balancer to route all requests to VM2 at a specified time?

Answer 1

Hello @Josh Monreal

Welcome to Microsoft Q&A Platform,

Azure Load Balancer works at layer 4 hence won't check that at application layer:

https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-overview

If you want to to check to check that you may want yo use an Application Gateway which works at layer 7:

https://learn.microsoft.com/en-us/azure/application-gateway/overview

I hope this helps!

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