[libvirt] A question about create image for sheepdog

Hi everyone: I want to build a VM Manage System, and I use libvirt to create and delete VM. But now I has used sheepdog as the disk, but I have to create sheepdog image by hand. If I have a thousand of servers, how can I create the image? I think if I can write a API for create the sheepdog image by call the qemu-img or kvm-img? (My English is rather poor, please forgive me)