Azure Front Door Error

Question

We have implemented Front Door for our two app services, one in the active region and the other in the standby region. We have also configured a custom domain for the Front Door. However, when we hit the URL, it always directs the traffic to the standby region app service, and sometimes it displays an error message "Our services aren't available right now We're working to restore all services as soon as possible. Please check back soon." Can someone suggest a suitable solution for this issue? We want the Front Door to direct the traffic to the active region app service and avoid the error message.

Answer 1

Posting this answer for community benefit.

When such issues occur when Azure Front Door is not routing the issue to the correct backend. You can follow the steps mentioned below to get rid of this issue.

• Validate the health probe set-up for afd. Here you can check how Front Door determines backend health an only 200 response is considered as healthy.
• Enable diagnostic logging for your Front Door service and see if there are any issues with the health probes by running the query below in the log analytics workspace.

AzureDiagnostics |
where Category == "FrontDoorHealthProbeLog"

• Check if you have added your custom domain properly which destination as frontend host name.
• Check if you have set the interval to 5 (small value) so the front door knows if backend is down and that it shouldn’t routes traffic to that backend anymore.
• Make sure that you have checked all your frontends/domains in routing rules.

Thank you!