J'ai modifié /etc/realmd.conf pour préciser le bon chemin de la bonne OU. Mais ça n'est pas pris en compte comme indiqué là: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/windows_integration_guide/realmd-conf

Changing the configuration as described in this section only works if the realm join command has not been run yet. If a system is already joined, changing these settings does not have any effect. In such situations, you must leave the domain, as described in Section 3.5, “Removing a System from an Identity Domain”, and then join again, as described in the section called “Joining a Domain”.

J'ai peur de quitter/rejoindre le domaine...