Connect to a DBFS root external location (legacy)

This page describes how to connect to a Databricks File System (DBFS) root storage external location. After you connect, you can to govern access to objects in DBFS root storage using Unity Catalog.

Although Databricks recommends against storing data in DBFS root storage, your workspace might do so because of legacy practices. For example, your workspace-local, legacy Databricks Hive metastore might have stored data in the DBFS root. Follow this guide to connect to the DBFS root by first creating a storage credential object that allows access to the DBFS root, then an external location object that defines the path to the DBFS root. These objects allow you to connect to your legacy Hive metastore so that your team can work with your Hive metastore tables using Unity Catalog. See Hive metastore federation: enable Unity Catalog to govern tables registered in a Hive metastore and Enable Hive metastore federation for a legacy workspace Hive metastore.

Before you begin

To create an external location for the DBFS root, you must have a storage credential defined in Unity Catalog that gives access to the DBFS root’s cloud storage location. If you don't already have one, the system can create one for you during the process of creating the external location.

Permissions requirements:

• You must have the CREATE STORAGE CREDENTIAL and CREATE EXTERNAL LOCATION privileges on the metastore. Metastore admins have these privileges by default.

  note

  If a storage credential for the DBFS root's storage location already exists, then the user who creates the external location does not need CREATE STORAGE CREDENTIAL, but does need CREATE EXTERNAL LOCATION on both the storage credential and the metastore.

• You must be a workspace admin to have the system create the storage credential for you during external location creation.

  You do not have to be a workspace admin if a storage credential that gives access to the DBFS root storage location already exists and you have CREATE EXTERNAL LOCATION on both the storage credential and the metastore.

Create the external location

You can use Catalog Explorer to create an external location for the DBFS root.

1. In the sidebar, click Catalog.

2. Click External data > and Create external location.

3. Enter an External location name.

4. For Storage type, select DBFS Root.

   The URL and subpath fields are populated with the cloud storage path to the DBFS root.

   important

   When you create an external location for the DBFS root, you must use the subpath to the DBFS root location, not the path to the entire bucket. The URL and subpath are pre-populated with user/hive/warehouse, which is the default storage location for Hive metastore tables. If you want more fine-grained access control to the data in DBFS root, you can create separate external locations for sub-paths within DBFS root.

5. Select a storage credential that grants access to the DBFS root cloud storage location or, if none has been defined, click + Create new storage credential.

   A storage credential is created automatically when you save the external location.

6. (Optional) Add a comment.

7. (Optional) Click Advanced options and enable Fallback mode.

   Fallback mode is intended for legacy workload migration scenarios. See Enable fallback mode on external locations.

8. Click Create.

9. Go to the Permissions tab to grant permission to use the external location.

   1. Click Grant.
   2. Select users, groups, or service principals in Principals field, and select the privilege you want to grant.
   3. Click Grant.

10. (Optional) Set the workspaces that can access this external location.

    By default, users on any workspace that uses this Unity Catalog metastore can be granted access to the data in this location. You can limit that access to specific workspaces. Databricks recommends limiting access to the workspace that the DBFS root is in.

    See Bind an external location to one or more workspaces.