… and there is a virt-builder image available. Get a Fedora 21 VM image in a few seconds:
$ virt-builder fedora-21 [ 2.0] Downloading: http://libguestfs.org/download/builder/fedora-21.xz [ 2.0] Planning how to build this image [ 2.0] Uncompressing [ 14.0] Opening the new disk [ 28.0] Setting a random seed [ 28.0] Setting passwords virt-builder: Setting random password of root to thu1hKRoXBxBigfC [ 29.0] Finishing off
Richard WM Jones 