def create_cow_image(backing_file, path, size=None): """Create COW image Creates a COW image with the given backing file :param backing_file: Existing image on which to base the COW image :param path: Desired location of the COW image """ base_cmd = [get_qemu_img_path(), 'create', '-f', 'qcow2'] cow_opts = [] if backing_file: cow_opts += ['backing_file=%s' % backing_file] base_details = images.qemu_img_info(backing_file) else: base_details = None # This doesn't seem to get inherited so force it to... # http://paste.ubuntu.com/1213295/ # TODO(harlowja) probably file a bug against qemu-img/qemu if base_details and base_details.cluster_size is not None: cow_opts += ['cluster_size=%s' % base_details.cluster_size] # For now don't inherit this due the following discussion... # See: http://www.gossamer-threads.com/lists/openstack/dev/10592 # if 'preallocation' in base_details: # cow_opts += ['preallocation=%s' % base_details['preallocation']] if base_details and base_details.encryption: cow_opts += ['encryption=%s' % base_details.encryption] if size is not None: cow_opts += ['size=%s' % size] if cow_opts: # Format as a comma separated list csv_opts = ",".join(cow_opts) cow_opts = ['-o', csv_opts] cmd = base_cmd + cow_opts + [path] execute(*cmd)
def get_disk_type(path): """Retrieve disk type (raw, qcow2, lvm) for given file.""" if path.startswith('/dev'): return 'lvm' elif path.startswith('rbd:'): return 'rbd' return images.qemu_img_info(path).file_format
def get_disk_size(path): """Get the (virtual) size of a disk image :param path: Path to the disk image :returns: Size (in bytes) of the given disk image as it would be seen by a virtual machine. """ size = images.qemu_img_info(path).virtual_size return int(size)
def get_disk_backing_file(path, basename=True): """Get the backing file of a disk image :param path: Path to the disk image :returns: a path to the image's backing store """ backing_file = images.qemu_img_info(path).backing_file if backing_file and basename: backing_file = os.path.basename(backing_file) return backing_file
def _get_driver_format(self): data = images.qemu_img_info(self.path) return data.file_format or 'raw'