Do Not Delete Your Azure Function Storage Account

We saw several storage accounts that hadn’t been updated since 2020 and thought we could delete them to save about $15 per month. We didn’t see anywhere it was used. So on a Monday, we deleted those storage accounts and noticed some Azure Functions stopped working.

A different team member:

Why isn’t our development Function not working? Oh no, our production function is down as well 💣😢

What are the exceptions? (No such host is known. (storageaccount{id}.blob.core.windows.net:443)) hmmm.

Asked in a Teams Channel, and “I deleted the blob storage”, “welp, here are the results of the scream test”.

How do we fix this?

We can recover the storage accounts with a few button clicks!

After that, the function started working and Metrics started showing executions again. Phew, back in business.

All in all, we lost about an hour, but the impact was minimal. We wrote up our incident review and I decided to share this with you.

How do we stop this from happening?

We added some Azure Management locks manually on the function and the storage accounts.

Other people had this same problem and it is documented

https://github.com/MicrosoftDocs/azure-docs/blob/main/articles/azure-functions/functions-recover-storage-account.md

I think that Azure should automatically protect the storage account for a function or at least make it obvious that it is for the storage account.

You can find if it is used in “either AzureWebJobsStorage or WEBSITE_CONTENTAZUREFILECONNECTIONSTRING contains the name of your storage account as part of a connection string”

via GIPHY