Found the solution and it's almost like you said @dice. This time we just created the cluster with the root user (didn't check the single user mode)   Besides, our host had no internet access, and having created our own repository we needed to do one last step before launching the cluster creation which is importing the GPG key on the host using this command :   sudo rpm --import <gpg_key_path>   If anybody finds themselves facing the same problem, hope this helps! ... View more