How to move custom domain from App Service to Front Door?

Question

We are going to configure/setup an additional Front Door between enduser and App Service. Right now a custom domain is configured to the App Service directly (and validated with TXT record). In future this domain should point to the Front Door endpoint directly. A downtime for this change must be avoided.

I assume it does not matter if Standard or Premium tier of FD is used. Is that correct?

What are the supported migration steps for a seemless switch of the config?

Answer 1

Hello @Kay Werner

Greetings!

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

Here are the steps you need to follow to achieve this:

1. You can achieve this, but you will experience some downtime. First, select the domain you want to move, then open the Front Door and choose the custom domain.
2. Next, add the custom domain and validate it with a TXT record. Once the validation process is complete, remove the CNAME or A record mapping for the existing app service record.
3. Finally, re-add the CNAME record mapping with the Azure Front Door endpoint name.
4. Before switching DNS records, test the Front Door endpoint to ensure it correctly routes traffic to the App Service.
5. Gradually update your DNS records to point to the Front Door endpoint.
6. Monitor traffic and ensure that users are being routed correctly without downtime.
7. Once the DNS changes have propagated and you confirm that traffic is flowing through Front Door, you can remove the direct App Service custom domain configuration.

NOTE: Both Standard and Premium tiers support custom domains, so you can choose based on your feature needs.

How to add Configure a custom domain on Azure Front Door

Refer: https://learn.microsoft.com/en-us/azure/frontdoor/standard-premium/how-to-add-custom-domain

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I hope this has been helpful!

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