the issue is that the qemu-kvm-ev rpm's released by centos have not been compiled with curl support, I rebuild it myself from source with curl support and it works fine now.
Thanks you for your input everyone.
From: Vasiliy Tolstov <v.tolstov@selfip.ru> Sent: 09 August 2018 10:32:07 To: Inception Hosting Cc: libvirt-users@redhat.com Subject: Re: [libvirt-users] Mount URL as cdrom/iso KVM/QEMU
ÓÒ, 8 Á×Ç. 2018 Ç. × 15:11, Inception Hosting <inbox@inceptionhosting.com>:
>
> Hi Folks,
>
>
> According to the examples in
http://libvirt.org/formatdomain.html#elementsDisks it should be possible to mount an iso /url as a cdrom, the example given is:
>
Usually such errors because url not available from host system. Can
you try curl this host and address from node?