Description of problem: If you use --format without --size, then you get an error: virt-builder fedora-19 --format qcow2 [ 0.0] Downloading: file:///home/rjones/d/libguestfs/builder/website/fedora-19.xz [ 1.0] Creating disk image: fedora-19.qcow2 [ 1.0] Uncompressing: file:///home/rjones/d/libguestfs/builder/website/fedora-19.xz [ 15.0] Running virt-resize to expand the disk to 4.0G virt-resize: error: You cannot use --expand when there is no surplus space to expand into. You need to make the target disk larger by at least 1.3M. virt-resize: If reporting bugs, run virt-resize with debugging enabled (-v) and include the complete output. virt-builder: error: virt-resize failed Version-Release number of selected component (if applicable): libguestfs 1.25.7. How reproducible: 100% Steps to Reproduce: 1. See command line above.
Fixed by: https://github.com/libguestfs/libguestfs/commit/62cc7d3361127b4e007f8e23028213852be09124