This is a libvirt question, so asking it on the qemu-block might not get you an answer that quick, ... or ever if I didn't notice your other question also addressed incorrectly. [adding libvirt-users@redhat.com to cc] On Tue, Sep 01, 2020 at 10:57:34 -0400, Yoonho Park wrote:

I am trying to perform a blockpull on an attached disk, but I cannot do this using "virsh attach-disk" specifying a new, empty overlay file created with "qemu-img create". The VM does not pick up the backing_file path from

Could you please elaborate on the exact steps? specifically the arguments for qemu-img create. My feeling is that you didn't specify the backing image format (-F) when creating the overlay, but it's hard to tell from this very sparse question.

the qcow2 overlay file, and there seems to be no way to specify the backing path through the attach-disk command itself. Instead the backing path has

virsh attach-disk is a syntax-sugar wrapper which generates the XML document which is in fact used to attach disk. You can use virsh attach-disk --print-xml to see what would be used.

to be specified in the xml file used to create the VM, which precludes attaching a new disk to a running VM. Is this a bug? Is it possible to

using virsh attach-device allows you to pass in a whole <devices> subelement such as <disk> with any configuration you are able to specify when defining the XML. The virsh attach-disk is limited to just "basic" config options.

attach a disk to a running VM, and specify its backing path, using qemu directly? This is with qemu 4.2.0 and libvirt 6.0.0.