Retrieve a debian mini iso from a Debian mirror site: https://www.debian.org/mirror/list
wget -P /tmp http://ftp.fr.debian.org/debian/dists/jessie/main/installer-amd64/current/images/netboot/mini.iso
Install a QEMU/KVM package on the server
wget -qO- /tmp http://cdn.trick77.com/vkvm-latest.tar.gz | tar xvz -C /tmp
Now, make the QEMU VNC server available on localhost:5900
/tmp/qemu-system-x86_64 -net nic -net user,hostfwd=tcp::80-:80,hostfwd=tcp::443-:443 -m 1024M -localtime -enable-kvm -hda /dev/vda -vnc 127.0.0.1:0 -cdrom /tmp/mini.iso -boot d