Resolved this morning, 


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?


--
Vasiliy Tolstov,
e-mail: v.tolstov@selfip.ru