First I had to run remotely a browser on the server, the only way to
upload
files on the storage attached to it.
Probably too late, but FIY, there's also an option to do it from command line
using ovirt-sdk [1]. You can use upload_disk example [2]. This is also very
use useful when you need to upload many images.
[1]
https://github.com/oVirt/ovirt-engine-sdk/
[2]
https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/
upload_disk.py