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Common Access Management Queries

Self-managed

If you are working with self-managed ClickHouse please see SQL users and roles.

This article shows the basics of defining SQL users and roles and applying those privileges and permissions to databases, tables, rows, and columns.

Admin user​

ClickHouse Cloud services have an admin user, default, that is created when the service is created. The password is provided at service creation, and it can be reset by ClickHouse Cloud users that have the Admin role.

When you add additional SQL users for your ClickHouse Cloud service, they will need a SQL username and password. If you want them to have administrative-level privileges, then assign the new user(s) the role default_role. For example, adding user clickhouse_admin:

Note

When using the SQL Console, your SQL statements will not be run as the default user. Instead, statements will be run as a user named sql-console:${cloud_login_email}, where cloud_login_email is the email of the user currently running the query.

These automatically generated SQL Console users have the default role.

Passwordless authentication​

There are two roles available for SQL console: sql_console_admin with identical permissions to default_role and sql_console_read_only with read-only permissions.

Admin users are assigned the sql_console_admin role by default, so nothing changes for them. However, the sql_console_read_only role allows non-admin users to be granted read-only or full access to any instance. An admin needs to configure this access. The roles can be adjusted using the GRANT or REVOKE commands to better fit instance-specific requirements, and any modifications made to these roles will be persisted.

Granular access control​

This access control functionality can also be configured manually for user-level granularity. Before assigning the new sql_console_* roles to users, SQL console user-specific database roles matching the namespace sql-console-role:<email> should be created. For example:

When a matching role is detected, it will be assigned to the user instead of the boilerplate roles. This introduces more complex access control configurations, such as creating roles like sql_console_sa_role and sql_console_pm_role, and granting them to specific users. For example:

Test admin privileges​

Log out as the user default and log back in as user clickhouse_admin.

All of these should succeed:

Non-admin users​

Users should have the privileges necessary, and not all be admin users. The rest of this document provides example scenarios and the roles required.

Preparation​

Create these tables and users to be used in the examples.

Creating a sample database, table, and rows​

  1. Create a test database

  2. Create a table

  3. Populate the table with sample rows

  4. Verify the table:

  5. Create a regular user that will be used to demonstrate restrict access to certain columns:

  6. Create a regular user that will be used to demonstrate restricting access to rows with certain values:

Creating roles​

With this set of examples:

  • roles for different privileges, such as columns and rows will be created
  • privileges will be granted to the roles
  • users will be assigned to each role

Roles are used to define groups of users for certain privileges instead of managing each user separately.

  1. Create a role to restrict users of this role to only see column1 in database db1 and table1:

  2. Set privileges to allow view on column1

  3. Add the column_user user to the column1_users role

  4. Create a role to restrict users of this role to only see selected rows, in this case, only rows containing A in column1

  5. Add the row_user to the A_rows_users role

  6. Create a policy to allow view on only where column1 has the values of A

  7. Set privileges to the database and table

  8. grant explicit permissions for other roles to still have access to all rows

    Note

    When attaching a policy to a table, the system will apply that policy, and only those users and roles defined will be able to do operations on the table, all others will be denied any operations. In order to not have the restrictive row policy applied to other users, another policy must be defined to allow other users and roles to have regular or other types of access.

Verification​

Testing role privileges with column restricted user​

  1. Log into the clickhouse client using the clickhouse_admin user

  2. Verify access to database, table and all rows with the admin user.

  3. Log into the ClickHouse client using the column_user user

  4. Test SELECT using all columns

    Note

    Access is denied since all columns were specified and the user only has access to id and column1

  5. Verify SELECT query with only columns specified and allowed:

Testing role privileges with row restricted user​

  1. Log into the ClickHouse client using row_user

  2. View rows available

    Note

    Verify that only the above two rows are returned, rows with the value B in column1 should be excluded.

Modifying Users and Roles​

Users can be assigned multiple roles for a combination of privileges needed. When using multiple roles, the system will combine the roles to determine privileges, the net effect will be that the role permissions will be cumulative.

For example, if one role1 allows for only select on column1 and role2 allows for select on column1 and column2 then the user will have access to both columns.

  1. Using the admin account, create new user to restrict by both row and column with default roles

  2. Remove prior privileges for A_rows_users role

  3. Allow A_row_users role to only select from column1

  4. Log into the ClickHouse client using row_and_column_user

  5. Test with all columns:

  6. Test with limited allowed columns:

Troubleshooting​

There are occasions when privileges intersect or combine to produce unexpected results, the following commands can be used to narrow the issue using an admin account

Listing the grants and roles for a user​

List roles in ClickHouse​

Display the policies​

View how a policy was defined and current privileges​

Example commands to manage roles, policies, and users​

The following commands can be used to:

  • delete privileges
  • delete policies
  • unassign users from roles
  • delete users and roles
Tip

Run these commands as an admin user or the default user

Remove privilege from a role​

Delete a policy​

Unassign a user from a role​

Delete a role​

Delete a user​

Summary​

This article demonstrated the basics of creating SQL users and roles and provided steps to set and modify privileges for users and roles. For more detailed information on each please refer to our user guides and reference documentation.