On Wed, May 30, 2018 at 11:58 AM Richard W.M. Jones <rjones@redhat.com> wrote:
On Wed, May 30, 2018 at 12:11:21AM +0300, Nir Soffer wrote:
Exporting images or ova files:
image in any format -> qemu-img -> [qcow2 byte stream] -> imageio http server -> http client
You can do this with nbdkit + plugin, it's exactly what we do today for virt-v2v:
https://github.com/libguestfs/libguestfs/blob/master/v2v/rhv-upload-plugin.p...
This is not the flow we are looking for. We need a way to read qcow2 data from a pipe.
Importing images or ova files:
http client -> imageio http server -> [qcow2 byte stream] -> qemu-img -> image in any format
Also could be done with nbdkit + plugin, basically the reverse of the above.
If you can create a tar file that reserves space for the image file without actually writing it, a possible workaround today would be using the offset/size runtime options of the raw driver to convert directly into a region inside the tar archive.
What are the offset/size runtime options? I cannot find anything about them in man qemu-img.
See:
https://github.com/libguestfs/libguestfs/blob/dd162d2cd56a2ecf4bcd40a7f46394...
But in any case you can just use the nbdkit tar plugin which already does all of this.
Can it work with a tar stream read from stdin, or it requires a tar file? Nir