Hi @NielsMH ,

I think there is small issue with your template. You missed variables mapping at the top level.

According to the documentation: 

"The bundles settings file can contain one top-level variables mapping to specify variable settings to use."

Add env variable to the root level. Then the error that is saying that you didn't define variable should vanished. 

And you can override top level variables with target mapping, as in your example 😉

https://learn.microsoft.com/en-us/azure/databricks/dev-tools/bundles/settings#targets