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Summary
This article helps troubleshoot the 'Something went wrong' error message when trying to browse through folders within a new Azure Data Lake (Azure Storage) source in Dremio.
Relevant Versions
All versions of Dremio and deployment types.
Reported Issue
After creating a new Azure Data Lake (Azure Storage) source in Dremio using the 'Azure Active Directory' Authentication option, browsing the source folders causes a 'Something went wrong' error message banner to pop-up on the Dremio UI.
The below java.lang.NullPointerException and related error will be seen in the server.log
of the coordinator node.
2023-03-30 10:27:01,207 [qtp800943608-440015] ERROR c.d.d.server.GenericExceptionMapper - Unexpected exception when processing GET http://<dremio host>/apiv2/source/<ADLS source name>/folder/files/?nocache=1680172021164 : java.lang.NullPointerException
java.lang.NullPointerException: null
... (stack trace omitted for brevity) ...
Cause
This occurs due to Azure AD configuration issues with a likely incorrect OAuth 2.0 Token Endpoint being specified in the original source settings when connecting to Azure storage through the Dremio UI.
To further prove an incorrect OAuth 2.0 Token Endpoint was specified in the ADLS source settings, it is possible to test and temporarily change the Authentication type to use the Shared Access Key method instead, which should yield a successful connection and allow browsing of source ADLS files and folders in Dremio without error.
Steps to Resolve
Ensure that the OAuth 2.0 Token Endpoint specified in the source settings is in the below format.
https://login.microsoftonline.com/<tenant_id>/oauth2/v2.0/token
Troubleshooting Steps
1. Verify that you are getting java.lang.NullPointerException: null
in the coordinator/master pod server.log.
2. Right-click on the Azure Storage source and while in the 'General' tab, then go to down to the 'Authentication' section.
3. Check the string value entered for the 'OAuth 2.0 Token Endpoint' field.
4. If OAuth Token Endpoint value does not conform to the above format, correct it.
Tips & Tricks
Any front-end network inspect network activity tests for example with Chrome Developer tools (F12), will also show HTTP 500
- Internal Server Error for one or more GET calls against the ADLS folders.
Additional Resources
Dremio documentation on Configuring Azure Storage as a Source: https://docs.dremio.com/current/sonar/data-sources/object/azure-storage/#configuring-azure-storage-as-a-source