From DISK to QCOW2 image

qemu-img convert -p -f raw -O qcow2 /dev/sda /mnt/images/disk.qcow2

From QCOW2 to raw DISK

qemu-img convert -p -f qcow2 -O raw /mnt/images/disk.qcow2 /dev/sda

Kali linux live DVD iso

• https://www.kali.org/get-kali/#kali-live