Thanks Sandro for your suggests.
I followed your instructions and all work perfectly.
The only problem that I found was the iso-domain that was not working properly then I have
destroy it and I recreate it and now work.
At the moment my hosts are installed with centos not ovirt-node. In the future I would
like to reinstall them with ovirt-node iso.
Is it possible? I only put in maintenance a then reinstall one by one with ovirt-node or I
must remove from engine and then reinstall one by one?