Best practices to consider when updating postgres user account

In some cases, considerations about organizations sometimes renaming the default postgres and enterprisedb superuser accounts can be needed for security or audit compliance reasons. Now while it can be technically, possible to use the ALTER ROLE command, renaming these accounts introduces functional and operational risks due to system dependencies on these roles.

Renaming the postgres or enterprisedb users can lead to several issues, including but not limited to:

1. Ownership and system object dependencies

   • These user accounts often own critical system objects such as databases, schemas, extensions, and tables.
   • Renaming these curcial accounts does not automatically update ownership references, which can break internal functions or many need extensive manual corrections.

2. Replication and high availability issues

   • Alot of general replication configurations may reference these roles, which can cause authentication failures for standby nodes.
   • Other Failover mechanisms such as Patroni, EnterpriseDB Failover Manager (EFM), and BDR/PGD may fail if these roles are renamed as they are dependent on these

3. Backup and restore complications

   • If you consider backup tools like Barman it can store ownership information in dump files. If the role is renamed, restores can fail or require manual intervention to reconfigure ownership.

4. Extension and third-party tool compatibility issues

   • In most cases, some certain PostgreSQL extensions and other third-party monitoring tools assume the presence of the default postgres user. Thus, renaming it can cause unexpected failures or prevent certain utilities from functioning correctly.

5. Application and script failures

   • There are cases where some applications and scripts explicitly reference the postgres or enterprisedb user
   • If hardcoded usernames exist in stored procedures or functions, renaming can lead to runtime errors.

6. Maintenance risks

   • PostgreSQL and EPAS major version upgrades assume that postgres exists.
   • Renaming may require additional manual interventions during upgrades and patches.

Instead of flat out renaming the default user, consider securing the account while ensuring system stability:

1. Restrict the account to prevent interactive logins

   • You can use the following command to disable interactive logins:

     sudo usermod -L -e 1 postgres -s /sbin/nologin

   • This will prevent direct access whilst maintaining the account for general internal system operations.

2. Verify the restrictions

   • If you try attempting to switch to the postgres user, it should fail as seen in the example below:

     su - postgres
     Password:
     su: Authentication failure

   • However, as seen in the example below; the Postgres service should continue running as expected:

     psql -U postgres
     psql (15.8)
     Type "help" for help.

3. Now, create a new superuser and use Role-Based Access Control (RBAC)

   • Instead of just renaming, be sure to create an alternative superuser role with a different name and disable login for postgres or enterprisedb. Also, ensure that applications and scripts reference the new superuser instead of the default one.

While it is possible to rename postgres or enterprisedb, it can for sure introduce significant risks affecting database stability, replication, backup/restore processes, and third-party tool compatibility, if not propely cobfigured. A safer approach would be to secure these accounts while creating an alternative superuser role where necessary.

For further details, refer to the official PostgreSQL documentation: ALTER ROLE.