https://docs.redhat.com/en/documentation/red_hat_openstack_platform/17.1/html-single/hardening_red_hat_openstack_platform/index#proc_rotating-service-account-passwords_security-enhancements

This procedure only updates the overcloud-passwords.yaml file. It does not actually change the passwords on the overcloud. This section should make this clear that this additional step (overcloud deployment) is needed to complete the password change.