App Gateway Azure diagnostics logs and App Services

Question

We have a sitecore application hosted on azure app services. The applications requests will be hitting cloud fare, which will route it to the application gateway which in turn route the traffic to individual app services.

We have hosted in two regions(UK south and UK West) to support the failure cases with azure in case of any events with UK south being the primary and UK north being the secondary. The request will be routed to UK West by cloudflare only when app services on UK south flags unhealthy or They fail the condition of responding to health request by cloudflare.

The conditions are time taken to respond (not more than 5 secs and retries for 3 times)
and whether the health check is 200 or not.

We could see that the Cloudflare is alerting multiple times even when the above conditions are not met.

Now my million dollar question...

Does the app gateway and the app services records all the requests even if

1. the requests that got timed out
2. The request's that were never served response.

Before blaming the cloudfare, I would like to make sure that the above always logs all the requests.

Can you help me and provide, is there any chance that few requests get missed being logged??
Pls let me know if more information is required.

Answer 1

@saimurali makala ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you would like to know if Application Gateway diagnostic logs and App Service HTTP Logs logs every HTTP request it receives.

For Application Gateway, yes, every HTTP request is logged.

To answer your question,

1.the requests that got timed out

• Yes
• If there is a timeout from backend or if the backend closed the connection abruptly, the Application Gateway will give you a 5XX Error and it is logged as well

2.The request's that were never served response

• There will never be such a case
• App gateway will always give a response
• As mentioned in #1 - if the backend took more time than the Request timeout configured in HTTP Settings, App gateway will send a 5XX and log it.

The same logic should apply for Azure App Service logs as well, I shall check internally and confirm as soon as possible.

Cheers,

Kapil