App Service Slot Deployed with Wrong Hostname

App service slot keeps getting deployed with a hostname different than requested. Azure is adding random characters to the slot hostname.
For example, xxx-xx-xx-xx-stgb8e7.azurewebsites.net, the expected hostname is xxx-xx-xx-xx-stg.azurewebsites.net. The characyters "b8e7" are added by Azure.
This started happening after the slot was deleted and re-created.

brtrach-MSFT 15,176 Reputation points Microsoft Employee

2022-03-02T05:24:05.97+00:00

We have reached out to @Kamoji, Koichiro J (KKAMOJI) as we believe this warrants a technical review by support. If the community has any inputs or suggestions, please share them here.
Kamoji, Koichiro J (KKAMOJI) 6 Reputation points

2022-03-02T19:01:13.797+00:00

Hi @brtrach-MSFT I verified that the DNS xxx-xx-xx-xx-stg.azurewebsites.net is available. This hostname was used by the exact app service before it was deleted. Upon deployment, Azure should register a custom domain for the deployment slot with the name http://xxx-xx-xx-xx-stg.azurewebsites.net/ and not http://xxx-xx-xx-xx-stgb8e7.azurewebsites.net/
This is happening on a couple of different app services. Other users also reported the issue in the past: https://stackoverflow.com/questions/51791665/deleted-an-azure-app-service-slot-and-now-i-cant-get-the-original-hostname-back
brtrach-MSFT 15,176 Reputation points Microsoft Employee

2022-03-07T03:41:15.767+00:00

@Kamoji, Koichiro J (KKAMOJI) Thank you for the update. Can you please follow the steps we sent in the above private message to reach out to us via email?

Thank you.
arwin 0 Reputation points

2023-01-31T15:08:02.5666667+00:00

Any update on this issue?

1 answer

Alistair Ross 7,101 Reputation points Microsoft Employee

2023-01-31T15:22:03.34+00:00

Hello

This behaviour is expected as per our documentation

"The slot's URL will be of the format http://sitename-slotname.azurewebsites.net. To keep the URL length within necessary DNS limits, the site name will be truncated at 40 characters, the slot name will be truncated at 19 characters, and an additional 4 random characters will be appended to ensure the resulting domain name is unique."

https://learn.microsoft.com/en-us/azure/app-service/deploy-staging-slots#add-a-slot

I hope this helps provide you with the information you need. If it does, please make sure to mark the question as answered so it helps other people in future.

Kind regards

Alistair
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arwin 0 Reputation points

2023-02-01T01:34:42.26+00:00

Hi @Alistair Ross

I verified that previous slot's URL seems available using www.digwebinterface.com.

azurewebsites.net. 60 IN SOA ns1-224.azure-dns.com. msnhst.microsoft.com. 2029458736 900 300 604800 60

We have been using the same script to recreate slot for the past 3 years. Is there any chance or time limit to reuse the URL?
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