Role-based access overview

How role-based access control works

Role-based access control (RBAC) consists of a collection of permissions on resources given to roles.

Roles

Roles in YSQL can represent individual users or a group of users. They encapsulate a set of privileges that can be assigned to other roles (or users). Roles are essential to implementing and administering access control on a YugabyteDB cluster. Below are some important points about roles:

  • Roles which have LOGIN privilege are users. Hence, all users are roles, but not all roles are users.

  • Roles can be granted to other roles, making it possible to organize roles into a hierarchy.

  • Roles inherit the privileges of all other roles granted to them.

YugabyteDB inherits a number of roles from PostgreSQL, including the postgres user, and adds several new roles. View the YugabyteDB-specific roles for your clusters with the following command (or use \duS to display all roles):

yugabyte=> \du

                                     List of roles
  Role name   |                         Attributes                         | Member of
--------------+------------------------------------------------------------+-----------
 postgres     | Superuser, Create role, Create DB, Replication, Bypass RLS | {}
 yb_db_admin  | No inheritance, Cannot login                               | {}
 yb_extension | Cannot login                                               | {}
 yb_fdw       | Cannot login                                               | {}
 yugabyte     | Superuser, Create role, Create DB, Replication, Bypass RLS | {}

The following table describes the default YSQL roles and users in YugabyteDB clusters.

Role Description
postgres Superuser role created during database creation.
yb_db_admin Role that allows non-superuser users to create tablespaces and perform other privileged operations.
yb_extension Role that allows non-superuser users to create PostgreSQL extensions.
yb_fdw Role that allows non-superuser users to CREATE, ALTER, and DROP foreign data wrappers.
yugabyte Superuser role used during database creation, by Yugabyte support to perform maintenance operations, and for backups (using ysql_dump).

yb_extension

The yb_extension role allows non-superuser roles to create extensions. A user granted this role can create all the extensions that are bundled in YugabyteDB.

Create a role test and grant yb_extension to this role.

yugabyte=# create role test;
yugabyte=# grant yb_extension to test;
yugabyte=# set role test;
yugabyte=> select * from current_user;

 current_user
--------------
 test
(1 row)

Create an extension as the test user and check if it's created.

yugabyte=> create extension pgcrypto;
yugabyte=> select * from pg_extension where extname='pgcrypto';

 extname  | extowner | extnamespace | extrelocatable | extversion | extconfig | extcondition
----------+----------+--------------+----------------+------------+-----------+--------------
 pgcrypto |    16386 |         2200 | t              | 1.3        |           |
(1 row)

Resources

YSQL defines a number of specific resources that represent underlying database objects. A resource can represent one object or a collection of objects. YSQL resources are hierarchical as described below:

  • Databases and tables follow the hierarchy: ALL DATABASES > DATABASE > TABLE
  • ROLES are hierarchical (they can be assigned to other roles). They follow the hierarchy: ALL ROLES > ROLE #1 > ROLE #2 ...

The table below lists out the various resources.

Resource Description
DATABASE Denotes one database. Typically includes all the tables and indexes defined in that database.
TABLE Denotes one table. Includes all the indexes defined on that table.
ROLE Denotes one role.
ALL DATABASES Collection of all databases in the database.
ALL ROLES Collection of all roles in the database.

Privileges

Privileges are necessary to execute operations on database objects. Privileges can be granted at any level of the database hierarchy and are inherited downwards. The set of privileges include:

Privilege Objects Operations
ALTER database, table, role ALTER
AUTHORIZE database, table, role GRANT privilege, REVOKE privilege
CREATE database, table, role, index CREATE
DROP database, table, role, index DROP
MODIFY database, table INSERT, UPDATE, DELETE, TRUNCATE
SELECT database, table SELECT

Note

The ALTER TABLE privilege on the base table is required in order to CREATE or DROP indexes on it.

Read more about YSQL privileges.