Azure Data Factory (ADF) dataflow seems to pick the wrong endpoint when Data Preview

Question

I have created a storage account/blob storage StorageV2 in Azure. Inside it I have created a container. Storage account automatically creates endpoints for all the provided services

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Then in ADF I have created a linked service (user assigned managed identity/ private endpoint) which is pointing to azure blob storage/ file.csv

The connection is tested and works fine.

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Later on, I create a dataset using this linked service and I capable of previewing the data just fine

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Finally, inside a new dataflow I create a source activity when I specify the above mentioned dataset.

When I hit the Data Preview tab I get the below error

This happens only inside a dataflow

From the error message I realize that ADF send the request to the wrong endpoint (data lake instead of blob service).

Why does this happen? How can I change it?

Answer 1

Add Storage Account Contributor with Storage Blob Data Contributor.

Answer 2

Operation failed: "This request is not authorized to perform this operation.", 403, HEAD, https://xxxx/.dfs.core.windows.net/?upn=false&action=getAccessControl&timeout=90When using Managed Identity(MI)/Service Principal(SP) authentication

First of all, as per the error It seems like permission issue you need to grant proper permissions to access the Blob Storage using User Assigned managed identity and also check the firewall is not causing any issue.

Regarding the ADF taking .dfs(Data Lake) endpoint while previewing the data is as per this document in dataflow Azure Blob Storage events, soft delete or automatic snapshot isn't supported if the Azure Blob Storage linked service is created with service principal or managed identity authentication. this is the reason you are seeing .dfs endpoint while previewing data in data flow.

So, if you want to use service principal or managed identity authentication while creating linked service for blob storage you need to disable Azure Blob Storage events, soft delete or automatic snapshot as shown in below image or you can use Account key to authenticate.