PostgreSQL Role management ========================== .. raw:: html From its inception, CloudNativePG has managed the creation of specific roles required in PostgreSQL instances: - some reserved users, such as the ``postgres`` superuser, ``streaming_replica`` and ``cnpg_pooler_pgbouncer`` (when the PgBouncer ``Pooler`` is used) - The application user, set as the low-privilege owner of the application database This process is described in the :ref:`Bootstrap ` section. With the ``managed`` stanza in the cluster spec, CloudNativePG now provides full lifecycle management for roles specified in ``.spec.managed.roles`` . This feature enables declarative management of existing roles, as well as the creation of new roles if they are not already present in the database. Role creation will occur *after* the database bootstrapping is complete. An example manifest for a cluster with declarative role management can be found in the file `cluster-example-with-roles.yaml `_ . Here is an excerpt from that file: .. code:: yaml apiVersion: postgresql.cnpg.io/v1 kind: Cluster spec: managed: roles: - name: dante ensure: present comment: Dante Alighieri login: true superuser: false inRoles: - pg_monitor - pg_signal_backend The role specification in ``.spec.managed.roles`` adheres to the `PostgreSQL structure and naming conventions `_ . Please refer to the :ref:`API Reference ` for the full list of attributes you can define for each role. A few points are worth noting: 1. The ``ensure`` attribute is **not** part of PostgreSQL. It enables declarative role management to create and remove roles. The two possible values are ``present`` (the default) and ``absent`` . 2. The ``inherit`` attribute is true by default, following PostgreSQL conventions. 3. The ``connectionLimit`` attribute defaults to -1, in line with PostgreSQL conventions. 4. Role membership with ``inRoles`` defaults to no memberships. Declarative role management ensures that PostgreSQL instances align with the spec. If a user modifies role attributes directly in the database, the CloudNativePG operator will revert those changes during the next reconciliation cycle. Password management ------------------- The declarative role management feature includes reconciling of role passwords. Passwords are managed in fundamentally different ways in the Kubernetes world and in PostgreSQL, and as a result there are a few things to note. Managed role configurations may optionally specify the name of a **Secret** where the username and password are stored (encoded in Base64 as is usual in Kubernetes). For example: .. code:: yaml managed: roles: - name: dante ensure: present [… snipped …] passwordSecret: name: cluster-example-dante This would assume the existence of a Secret called ``cluster-example-dante`` , containing a username and password. The username should match the role we are setting the password for. For example, : .. code:: yaml apiVersion: v1 data: username: ZGFudGU= password: ZGFudGU= kind: Secret metadata: name: cluster-example-dante labels: cnpg.io/reload: "true" type: kubernetes.io/basic-auth If there is no ``passwordSecret`` specified for a role, the instance manager will not try to CREATE / ALTER the role with a password. This keeps with PostgreSQL conventions, where ALTER will not update passwords unless directed to with ``WITH PASSWORD`` . If a role was initially created with a password, and we would like to set the password to NULL in PostgreSQL, this necessitates being explicit on the part of the user of CloudNativePG. To distinguish “no password provided in spec” from “set the password to NULL”, the field ``DisablePassword`` should be used. Imagine we decided we would like to have no password on the ``dante`` role in the database. In such case we would specify the following: .. code:: yaml managed: roles: - name: dante ensure: present [… snipped …] disablePassword: true NOTE: it is considered an error to set both ``passwordSecret`` and ``disablePassword`` on a given role. This configuration will be rejected by the validation webhook. Password expiry, ``VALID UNTIL`` ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The ``VALID UNTIL`` role attribute in PostgreSQL controls password expiry. Roles created without ``VALID UNTIL`` specified get NULL by default in PostgreSQL, meaning that their password will never expire. PostgreSQL uses a timestamp type for ``VALID UNTIL`` , which includes support for the value ``'infinity'`` indicating that the password never expires. Please see the `PostgreSQL documentation `_ for reference. With declarative role management, the ``validUntil`` attribute for managed roles controls password expiry. ``validUntil`` can only take: - a Kubernetes timestamp, or - be omitted (defaulting to ``null`` ) In the first case, the given ``validUntil`` timestamp will be set in the database as the ``VALID UNTIL`` attribute of the role. In the second case (omitted ``validUntil`` ) the operator will ensure password never expires, mirroring the behavior of PostgreSQL. Specifically: - in case of new role, it will omit the ``VALID UNTIL`` clause in the role creation statement - in case of existing role, it will set ``VALID UNTIL`` to ``infinity`` if ``VALID UNTIL`` was not set to ``NULL`` in the database (this is due to PostgreSQL not allowing ``VALID UNTIL NULL`` in the ``ALTER ROLE`` SQL statement) .. Warning:: New roles created without `passwordSecret` will have a `NULL` password inside PostgreSQL. 　 Password hashed ^^^^^^^^^^^^^^^ You can also provide pre-encrypted passwords by specifying the password in MD5/SCRAM-SHA-256 hash format: .. code:: yaml kind: Secret type: kubernetes.io/basic-auth metadata: name: cluster-example-cavalcanti labels: cnpg.io/reload: "true" apiVersion: v1 stringData: username: cavalcanti password: SCRAM-SHA-256$:$: Unrealizable role configurations -------------------------------- In PostgreSQL, in some cases, commands cannot be honored by the database and will be rejected. Please refer to the `PostgreSQL documentation on error codes `_ for details. Role operations can produce such fundamental errors. Two examples: - We ask PostgreSQL to create the role ``petrarca`` as a member of the role (group) ``poets`` , but ``poets`` does not exist. - We ask PostgreSQL to drop the role ``dante`` , but the role ``dante`` is the owner of the database ``inferno`` . These fundamental errors cannot be fixed by the database, nor the CloudNativePG operator, without clarification from the human administrator. The two examples above could be fixed by creating the role ``poets`` or dropping the database ``inferno`` respectively, but they might have originated due to human error, and in such case, the “fix” proposed might be the wrong thing to do. CloudNativePG will record when such fundamental errors occur, and will display them in the cluster Status. Which segues into… Status of managed roles ----------------------- The Cluster status includes a section for the managed roles’ status, as shown below: .. code:: yaml status: […snipped…] managedRolesStatus: byStatus: not-managed: - app pending-reconciliation: - dante - petrarca reconciled: - ariosto reserved: - postgres - streaming_replica cannotReconcile: dante: - could not perform DELETE on role dante: owner of database inferno petrarca: - could not perform UPDATE_MEMBERSHIPS on role petrarca: role "poets" does not exist Note the special sub-section ``cannotReconcile`` for operations the database (and CloudNativePG) cannot honor, and which require human intervention. This section covers roles reserved for operator use and those that are **not** under declarative management, providing a comprehensive view of the roles in the database instances. The :ref:`Kubectl Plugin ` also shows the status of managed roles in its ``status`` sub-command: .. code:: txt Managed roles status Status Roles - ----- ----- pending-reconciliation petrarca reconciled app,dante reserved postgres,streaming_replica Irreconcilable roles Role Errors - --- ------ petrarca could not perform UPDATE_MEMBERSHIPS on role petrarca: role "poets" does not exist .. Note:: In terms of backward compatibility, declarative role management is designed to ignore roles that exist in the database but are not included in the spec. The lifecycle of these roles will continue to be managed within PostgreSQL, allowing CloudNativePG users to adopt this feature at their convenience.