Python libvirt.create_local_disk函数代码示例

def create_attach_xml(update_xmlfile, disk_type, target_bus,
                      target_dev, source_iso="", disk_mode=""):
    """
    Create a xml file to update a device.

    :param update_xmlfile : path/file to save device XML
    :param source_iso : disk's source backing file.
    :param disk_type: disk's device type: cdrom or floppy
    :param target_bus: disk's target bus
    :param target_dev: disk's target device name
    :param disk_mode: readonly or shareable
    """
    if source_iso:
        libvirt.create_local_disk("iso", source_iso)
    disk_class = VMXML.get_device_class('disk')
    disk = disk_class(type_name='file')
    # Static definition for comparison in check_attach()
    disk.device = disk_type
    disk.target = dict(bus=target_bus, dev=target_dev)
    if source_iso:
        disk.driver = dict(name='qemu')
        disk.source = disk.new_disk_source(attrs={'file': source_iso})
        if disk_mode == "readonly":
            disk.readonly = True
        if disk_mode == "shareable":
            disk.share = True
    disk.xmltreefile.write()
    shutil.copyfile(disk.xml, update_xmlfile)

    def prepare_disk(path, disk_format):
        """
        Prepare the disk for a given disk format.
        """
        disk = {}
        # Check if we test with a non-existed disk.
        if os.path.split(path)[-1].startswith("notexist."):
            disk.update({"format": disk_format,
                         "source": path})

        elif disk_format == "scsi":
            scsi_option = params.get("virt_disk_device_scsi_option", "")
            disk_source = libvirt.create_scsi_disk(scsi_option)
            if disk_source:
                disk.update({"format": "scsi",
                             "source": disk_source})
            else:
                raise error.TestNAError("Get scsi disk failed")

        elif disk_format in ["iso", "floppy"]:
                disk_path = libvirt.create_local_disk(disk_format, path)
                disk.update({"format": disk_format,
                             "source": disk_path})
        elif disk_format == "nfs":
            nfs_disk_type = params.get("nfs_disk_type", None)
            disk.update(setup_nfs_disk(os.path.split(path)[-1], nfs_disk_type))

        elif disk_format == "iscsi":
            # Create iscsi device if needed.
            disk_dev = qemu_storage.Iscsidev(params, os.path.dirname(path),
                                             "iscsi")
            device_source = disk_dev.setup()
            logging.debug("iscsi dev name: %s", device_source)

            # Format the disk and make file system.
            open("/tmp/fdisk-cmd", "w").write("n\np\n\n\n\nw\n")
            output = utils.run("fdisk %s < /tmp/fdisk-cmd"
                               % device_source).stdout.strip()
            logging.debug("fdisk output: %s", output)
            output = utils.run("mkfs.ext3 %s1"
                               % device_source).stdout.strip()
            logging.debug("mkfs output: %s", output)
            device_source += "1"
            disk.update({"format": disk_format, "disk_dev": disk_dev,
                         "source": device_source})
        elif disk_format in ["raw", "qcow2"]:
            disk_size = params.get("virt_disk_device_size", "1")
            device_source = libvirt.create_local_disk(
                "file", path, disk_size, disk_format=disk_format)
            disk.update({"format": disk_format,
                         "source": device_source})

        return disk

    def prepare_disk(path, disk_format):
        """
        Prepare the disk for a given disk format.
        """
        disk = {}
        # Check if we test with a non-existed disk.
        if os.path.split(path)[-1].startswith("notexist."):
            disk.update({"format": disk_format,
                         "source": path})

        elif disk_format == "scsi":
            scsi_option = params.get("virt_disk_device_scsi_option", "")
            disk_source = libvirt.create_scsi_disk(scsi_option)
            if disk_source:
                disk.update({"format": "scsi",
                             "source": disk_source})
            else:
                raise error.TestNAError("Get scsi disk failed")

        elif disk_format in ["iso", "floppy"]:
            disk_path = libvirt.create_local_disk(disk_format, path)
            disk.update({"format": disk_format,
                         "source": disk_path})
        elif disk_format == "nfs":
            nfs_disk_type = params.get("nfs_disk_type", None)
            disk.update(setup_nfs_disk(os.path.split(path)[-1], nfs_disk_type))

        elif disk_format == "iscsi":
            # Create iscsi device if needed.
            image_size = params.get("image_size", "2G")
            device_source = libvirt.setup_or_cleanup_iscsi(
                is_setup=True, is_login=True, image_size=image_size)
            logging.debug("iscsi dev name: %s", device_source)

            # Format the disk and make file system.
            libvirt.mk_part(device_source)
            # Run partprobe to make the change take effect.
            utils.run("partprobe", ignore_status=True)
            libvirt.mkfs("%s1" % device_source, "ext3")
            device_source += "1"
            disk.update({"format": disk_format,
                         "source": device_source})
        elif disk_format in ["raw", "qcow2"]:
            disk_size = params.get("virt_disk_device_size", "1")
            device_source = libvirt.create_local_disk(
                "file", path, disk_size, disk_format=disk_format)
            disk.update({"format": disk_format,
                         "source": device_source})

        return disk

    def setup_nfs_disk(disk_name, disk_type, disk_format="raw"):
        """
        Setup nfs disk.
        """
        mount_src = os.path.join(test.tmpdir, "nfs-export")
        if not os.path.exists(mount_src):
            os.mkdir(mount_src)
        mount_dir = os.path.join(test.tmpdir, "nfs-mount")

        if disk_type in ["file", "floppy", "iso"]:
            disk_path = "%s/%s" % (mount_src, disk_name)
            device_source = libvirt.create_local_disk(disk_type, disk_path, "2",
                                                      disk_format=disk_format)
            #Format the disk.
            if disk_type in ["file", "floppy"]:
                cmd = ("mkfs.ext3 -F %s && setsebool virt_use_nfs true"
                       % device_source)
                if utils.run(cmd, ignore_status=True).exit_status:
                    raise error.TestNAError("Format disk failed")

        nfs_params = {"nfs_mount_dir": mount_dir, "nfs_mount_options": "ro",
                      "nfs_mount_src": mount_src, "setup_local_nfs": "yes",
                      "export_options": "rw,no_root_squash"}

        nfs_obj = nfs.Nfs(nfs_params)
        nfs_obj.setup()
        if not nfs_obj.mount():
            return None

        disk = {"disk_dev": nfs_obj, "format": "nfs", "source":
                "%s/%s" % (mount_dir, os.path.split(device_source)[-1])}

        return disk

def create_disk(vm_name, disk_iso, disk_type, target_dev, mode=""):
    """
    :param vm_name : vm_name
    :param disk_iso : disk's source backing file
    :param disk_type: disk's device type: cdrom or floppy
    :param target_dev: disk's target device name
    :param mode: readonly or shareable
    """
    libvirt.create_local_disk("iso", disk_iso)
    options = "--type %s --sourcetype=file --config" % disk_type
    if mode:
        options += " --mode %s" % mode
    try:
        virsh.attach_disk(vm_name, disk_iso, target_dev, options)
    except:
        os.remove(disk_iso)
        raise exceptions.TestFail("Failed to attach")

    def prepare_local_image():
        """
        Prepare a local image.

        :return: The path to the image file.
        """
        image_filename = params.get("image_filename", "raw.img")
        image_format = params.get("image_format", "raw")
        image_size = params.get("image_size", "1G")
        image_path = os.path.join(data_dir.get_tmp_dir(), image_filename)
        try:
            if image_format in ["raw", "qcow2"]:
                image_path = libvirt.create_local_disk("file",
                                                       image_path, image_size,
                                                       disk_format=image_format)
            else:
                test.cancel("We only test raw & qcow2 format for now.")
        except Exception as err:
            test.error("Error happens when prepare local image: %s", err)
        return image_path

    # Additional disk images.
    disks_img = []
    vmxml = vm_xml.VMXML.new_from_dumpxml(vm_name)
    try:
        for i in range(len(disks)):
            disk_xml = Disk(type_name=device_types[i])
            # If we are testing image file on iscsi disk,
            # mount the disk and then create the image.
            if test_file_img_on_disk:
                mount_path = "/tmp/diskimg"
                if utils.run("mkdir -p %s && mount %s %s"
                             % (mount_path, disks[i]["source"],
                                mount_path), ignore_status=True).exit_status:
                    raise error.TestNAError("Prepare disk failed")
                disk_path = "%s/%s.qcow2" % (mount_path, device_source_names[i])
                disk_source = libvirt.create_local_disk("file", disk_path, "1",
                                                        disk_format="qcow2")
                disks_img.append({"format": "qcow2",
                                  "source": disk_source, "path": mount_path})
            else:
                disk_source = disks[i]["source"]

            disk_xml.device = devices[i]

            if device_with_source:
                if device_types[i] == "file":
                    dev_attrs = "file"
                elif device_types[i] == "dir":
                    dev_attrs = "dir"
                else:
                    dev_attrs = "dev"
                source_dict = {dev_attrs: disk_source}

    vm.destroy(gracefully=False)

    # Back up xml file.
    backup_xml = vm_xml.VMXML.new_from_inactive_dumpxml(vm_name)

    # Create virtual device file.
    device_source_path = os.path.join(test.tmpdir, device_source_name)
    if test_block_dev:
        device_source = libvirt.setup_or_cleanup_iscsi(True)
        if not device_source:
            # We should skip this case
            raise error.TestNAError("Can not get iscsi device name in host")
        if test_logcial_dev:
            lv_utils.vg_create(vg_name, device_source)
            device_source = libvirt.create_local_disk("lvm",
                                                      size="10M",
                                                      vgname=vg_name,
                                                      lvname=lv_name)
            logging.debug("New created volume: %s", lv_name)
    else:
        if source_path and create_img:
            device_source = libvirt.create_local_disk(
                "file", path=device_source_path,
                size="1G", disk_format=device_source_format)
        else:
            device_source = device_source_name

    # if we are testing audit, we need to start audit servcie first.
    if test_audit:
        auditd_service = Factory.create_service("auditd")
        if not auditd_service.status():
            auditd_service.start()

#.........这里部分代码省略.........
    test_shareable = "yes" == params.get("virt_disk_test_shareable", "no")
    disk_source_path = test.virtdir

    # Backup vm xml files.
    vms_backup = []
    # We just use 2 VMs for testing.
    for i in range(2):
        vmxml_backup = vm_xml.VMXML.new_from_inactive_dumpxml(vm_names[i])
        vms_backup.append(vmxml_backup)

    try:
        # Create disk images if needed.
        disks = []
        if disk_format == "scsi":
            disk_source = libvirt.create_scsi_disk(scsi_options)
            if not disk_source:
                raise error.TestNAError("Get scsi disk failed.")
            disks.append({"format": "scsi", "source": disk_source})

        elif disk_format == "iscsi":
            # Create iscsi device if neened.
            image_size = params.get("image_size", "100M")
            disk_source = libvirt.setup_or_cleanup_iscsi(
                is_setup=True, is_login=True, image_size=image_size)
            logging.debug("iscsi dev name: %s", disk_source)
            # Format the disk and make the file system.
            libvirt.mk_part(disk_source, size="10M")
            libvirt.mkfs("%s1" % disk_source, "ext3")
            disk_source += "1"
            disks.append({"format": disk_format,
                          "source": disk_source})
        elif disk_format in ["raw", "qcow2"]:
            disk_path = "%s/test.%s" % (disk_source_path, disk_format)
            disk_source = libvirt.create_local_disk("file", disk_path, "1",
                                                    disk_format=disk_format)
            libvirt.mkfs(disk_source, "ext3")
            disks.append({"format": disk_format,
                          "source": disk_source})

        # Compose the new domain xml
        vms_list = []
        for i in range(2):
            vm = env.get_vm(vm_names[i])
            # Destroy domain first.
            if vm.is_alive():
                vm.destroy(gracefully=False)

            # Configure vm disk options and define vm
            vmxml = vm_xml.VMXML.new_from_dumpxml(vm_names[i])
            if disk_bus == "scsi":
                set_vm_controller_xml(vmxml)
            disk_sgio = ""
            if len(vms_sgio) > i:
                disk_sgio = vms_sgio[i]
            shareable = ""
            if len(vms_share) > i:
                shareable = vms_share[i]
            disk_xml = get_vm_disk_xml(disk_type, disk_source,
                                       sgio=disk_sgio, share=shareable,
                                       target=disk_target, bus=disk_bus,
                                       driver=disk_driver_options)
            if not hotplug:
                # If we are not testing hotplug,
                # add disks to domain xml and sync.
                vmxml.add_device(disk_xml)
                vmxml.sync()

                return True
        except ShellTimeoutError, detail:
            raise error.TestFail("unhotplug failed: %s, " % detail)

    tmp_dir = os.path.join(data_dir.get_tmp_dir(), "usb_hotplug_files")
    if not os.path.isdir(tmp_dir):
        os.mkdir(tmp_dir)

    try:
        result = None
        dev_xml = None
        opt = "--hmp"
        for i in range(attach_count):
            if usb_type == "storage":
                path = os.path.join(tmp_dir, "%s.img" % i)
                libvirt.create_local_disk("file", path, size="1M", disk_format="qcow2")
                os.chmod(path, 0666)

            if attach_type == "qemu_monitor":
                if usb_type == "storage":
                    attach_cmd = "drive_add"
                    attach_cmd += (" 0 id=drive-usb-%s,if=none,file=%s" % (i, path))

                    result = virsh.qemu_monitor_command(vm_name, attach_cmd, options=opt)
                    if result.exit_status or (result.stdout.find("OK") == -1):
                        raise error.CmdError(result.command, result)

                    attach_cmd = "device_add usb-storage,"
                    attach_cmd += ("id=drive-usb-%s,bus=usb1.0,drive=drive-usb-%s" % (i, i))
                else:
                    attach_cmd = "device_add"

def run(test, params, env):
    """
    Test for hotplug usb device.
    """
    # get the params from params
    vm_name = params.get("main_vm", "avocado-vt-vm1")
    vm = env.get_vm(vm_name)

    usb_type = params.get("usb_type", "kbd")
    attach_type = params.get("attach_type", "attach_device")
    attach_count = int(params.get("attach_count", "1"))
    if usb_type == "storage":
        model = params.get("model", "nec-xhci")
        index = params.get("index", "1")
    status_error = ("yes" == params.get("status_error", "no"))

    vm_xml = VMXML.new_from_inactive_dumpxml(vm_name)
    vm_xml_backup = vm_xml.copy()

    # Set selinux of host.
    backup_sestatus = utils_selinux.get_status()
    utils_selinux.set_status("permissive")

    if usb_type == "storage":
        controllers = vm_xml.get_devices(device_type="controller")
        devices = vm_xml.get_devices()
        for dev in controllers:
            if dev.type == "usb" and dev.index == "1":
                devices.remove(dev)
        controller = Controller("controller")
        controller.type = "usb"
        controller.index = index
        controller.model = model
        devices.append(controller)
        vm_xml.set_devices(devices)

    try:
        session = vm.wait_for_login()
    except (LoginError, VMError, ShellError) as e:
        test.fail("Test failed: %s" % str(e))

    def is_hotplug_ok():
        try:
            output = session.cmd_output("fdisk -l | grep -c '^Disk /dev/.* 1 M'")
            if int(output.strip()) != attach_count:
                return False
            else:
                return True
        except ShellTimeoutError as detail:
            test.fail("unhotplug failed: %s, " % detail)

    tmp_dir = os.path.join(data_dir.get_tmp_dir(), "usb_hotplug_files")
    if not os.path.isdir(tmp_dir):
        os.mkdir(tmp_dir)

    try:
        result = None
        dev_xml = None
        opt = "--hmp"
        for i in range(attach_count):
            if usb_type == "storage":
                path = os.path.join(tmp_dir, "%s.img" % i)
                libvirt.create_local_disk("file", path, size="1M", disk_format="qcow2")
                os.chmod(path, 0o666)

            if attach_type == "qemu_monitor":
                if usb_type == "storage":
                    attach_cmd = "drive_add"
                    attach_cmd += (" 0 id=drive-usb-%s,if=none,file=%s" % (i, path))

                    result = virsh.qemu_monitor_command(vm_name, attach_cmd, options=opt)
                    if result.exit_status or (result.stdout.strip().find("OK") == -1):
                        raise process.CmdError(result.command, result)

                    attach_cmd = "device_add usb-storage,"
                    attach_cmd += ("id=drive-usb-%s,bus=usb1.0,drive=drive-usb-%s" % (i, i))
                else:
                    attach_cmd = "device_add"
                    attach_cmd += " usb-%s,bus=usb1.0,id=%s%s" % (usb_type, usb_type, i)

                result = virsh.qemu_monitor_command(vm_name, attach_cmd, options=opt)
                if result.exit_status:
                    raise process.CmdError(result.command, result)
            else:
                attributes = {'type_name': "usb", 'bus': "1", 'port': "0"}
                if usb_type == "storage":
                    dev_xml = Disk(type_name="file")
                    dev_xml.device = "disk"
                    dev_xml.source = dev_xml.new_disk_source(**{"attrs": {'file': path}})
                    dev_xml.driver = {"name": "qemu", "type": 'qcow2', "cache": "none"}
                    dev_xml.target = {"dev": 'sdb', "bus": "usb"}
                    dev_xml.address = dev_xml.new_disk_address(**{"attrs": attributes})
                else:
                    if usb_type == "mouse":
                        dev_xml = Input("mouse")
                    elif usb_type == "tablet":
                        dev_xml = Input("tablet")
                    else:
                        dev_xml = Input("keyboard")

#.........这里部分代码省略.........

#.........这里部分代码省略.........
            v2v_sasl.server_pwd = params.get('remote_pwd')
            v2v_sasl.setup(remote=True)
        if output_mode == 'local':
            v2v_params['storage'] = data_dir.get_tmp_dir()
        if output_mode == 'libvirt':
            pvt.pre_pool(pool_name, pool_type, pool_target, '')
        # Set libguestfs environment variable
        os.environ['LIBGUESTFS_BACKEND'] = 'direct'

        # Save origin graphic type for result checking if source is KVM
        if hypervisor == 'kvm':
            ori_vm_xml = vm_xml.VMXML.new_from_inactive_dumpxml(vm_name)
            params['ori_graphic'] = ori_vm_xml.xmltreefile.find(
                'devices').find('graphics').get('type')

        backup_xml = None
        # Only kvm guest's xml needs to be backup currently
        if checkpoint in backup_list and hypervisor == 'kvm':
            backup_xml = ori_vm_xml
        if checkpoint == 'multi_disks':
            new_xml = vm_xml.VMXML.new_from_inactive_dumpxml(
                vm_name, virsh_instance=v2v_virsh)
            disk_count = 0
            for disk in list(new_xml.get_disk_all().values()):
                if disk.get('device') == 'disk':
                    disk_count += 1
            if disk_count <= 1:
                test.error('Not enough disk devices')
            params['ori_disks'] = disk_count
        if checkpoint == 'sata_disk':
            change_disk_bus('sata')
        if checkpoint.startswith('floppy'):
            img_path = data_dir.get_tmp_dir() + '/floppy.img'
            utlv.create_local_disk('floppy', img_path)
            attach_removable_media('floppy', img_path, 'fda')
            if checkpoint == 'floppy_devmap':
                insert_floppy_devicemap()
        if checkpoint.startswith('fstab'):
            if checkpoint == 'fstab_cdrom':
                img_path = data_dir.get_tmp_dir() + '/cdrom.iso'
                utlv.create_local_disk('iso', img_path)
                attach_removable_media('cdrom', img_path, 'hdc')
            specify_fstab_entry(checkpoint[6:])
        if checkpoint == 'running':
            virsh.start(vm_name)
            logging.info('VM state: %s' %
                         virsh.domstate(vm_name).stdout.strip())
        if checkpoint == 'paused':
            virsh.start(vm_name, '--paused')
            logging.info('VM state: %s' %
                         virsh.domstate(vm_name).stdout.strip())
        if checkpoint == 'serial_terminal':
            grub_serial_terminal()
            check_boot()
        if checkpoint == 'no_space':
            @vm_shell
            def take_space(**kwargs):
                create_large_file(kwargs['session'], 20)
            take_space()
        if checkpoint.startswith('host_no_space'):
            session = aexpect.ShellSession('sh')
            create_large_file(session, 1000)
            if checkpoint == 'host_no_space_setcache':
                logging.info('Set LIBGUESTFS_CACHEDIR=/home')
                os.environ['LIBGUESTFS_CACHEDIR'] = '/home'
        if checkpoint == 'corrupt_rpmdb':

#.........这里部分代码省略.........
            pass
        if not guestmemory:
            # assign default memory
            guestmemory = default_mem

        # Set the current and max memory params
        vmxml.current_mem_unit = memunit
        vmxml.max_mem_unit = memunit
        vmxml.current_mem = int(guestmemory)
        vmxml.max_mem = int(guestmemory)
        vmxml.sync()

        # Set vcpu and topology
        libvirt_xml.VMXML.set_vm_vcpus(vm_name, max_vcpu, current_vcpu,
                                       vm_sockets, vm_cores, vm_threads)
        vmxml = libvirt_xml.VMXML.new_from_inactive_dumpxml(vm_name)

        # Set vnc display as needed
        graphics = vmxml.get_device_class('graphics')()
        if graphic:
            if not vmxml.get_graphics_devices("vnc"):
                graphics.add_graphic(vm_name, graphic="vnc")
        else:
            if vmxml.get_graphics_devices("vnc"):
                graphics.del_graphic(vm_name)
        vmxml = libvirt_xml.VMXML.new_from_inactive_dumpxml(vm_name)

        network_str = None
        disk_str = None
        # Set network devices
        if max_network:
            network_str = "ip link|grep ^[1-9]|wc -l"
            for idx in range(num_network):
                network = Interface(type_name="bridge")
                network.mac_address = utils_net.generate_mac_address_simple()
                network.source = {"bridge": netdst}
                vmxml.add_device(network)

        # Set disk devices
        if max_disk:
            for idx in range(num_disk):
                disk_str = "lsblk|grep ^[s,v]|grep 1G|wc -l"
                disk = Disk()
                disk_path = os.path.join(data_dir.get_data_dir(), "images", "%s.qcow2" % idx)
                if "scsi" in drive_format:
                    drive_format = "scsi"
                    disk_target = "sd%s" % letters[(idx % 51)+1]
                else:
                    drive_format = "virtio"
                    disk_target = "vd%s" % letters[(idx % 51)+1]
                disk_source = libvirt.create_local_disk("file", disk_path, '1', "qcow2")
                disk.device = "disk"
                disk.source = disk.new_disk_source(**{"attrs": {'file': disk_source}})
                disk.target = {"dev": disk_target, "bus": drive_format}
                disk.driver = {"name": "qemu", 'type': disk_format}
                vmxml.add_device(disk)
        vmxml.sync()

        # Start VM
        logging.debug("VM XML: \n%s", vmxml)
        try:
            vm.start()
        except virt_vm.VMStartError, detail:
            for msg in failures.items():
                if msg[0] in detail:
                    test.cancel("%s", msg[1])
            test.fail("%s" % detail)

        # Check the memory and vcpu inside guest
        memtotal = vm.get_totalmem_sys()
        cpucount = vm.get_cpu_count()
        session = vm.wait_for_login()
        if network_str:
            guestnetworks = int(session.cmd_output(network_str))
            logging.debug("guestnet: %d", guestnetworks)
            if (guestnetworks - 2) != num_network:
                failed = True
                logging.error("mismatch in guest network devices: \n"
                              "Expected: %d\nActual: %d", num_network,
                              guestnetworks)
        if disk_str:
            guestdisks = int(session.cmd_output(disk_str))
            logging.debug("guestdisk: %d", guestdisks)
            if guestdisks != num_disk:
                failed = True
                logging.error("mismatch in guest disk devices: \n"
                              "Expected: %d\nActual: %s", num_disk, guestdisks)
        session.close()
        guestmem = utils_misc.normalize_data_size("%s G" % guestmemory)
        # TODO:512 MB threshold deviation value, need to normalize
        if int(float(guestmem) - memtotal) > 512:
            failed = True
            logging.error("mismatch in guest memory: \nExpected: "
                          "%s\nActual: %s", float(guestmem), memtotal)
        if cpucount != current_vcpu:
            failed = True
            logging.error("mismatch in guest vcpu:\nExpected: %d\nActual: "
                          "%d", current_vcpu, cpucount)
        if failed:
            test.fail("Consult previous failures")

#.........这里部分代码省略.........
            vm.start()
            vm.wait_for_login().close()
    elif pre_vm_state == "shutoff":
        logging.info("Shuting down %s..." % vm_name)
        if vm.is_alive():
            vm.destroy(gracefully=False)
    elif pre_vm_state == "paused":
        logging.info("Pausing %s..." % vm_name)
        if vm.is_dead():
            vm.start()
            vm.wait_for_login().close()
        if not vm.pause():
            raise exceptions.TestSkipError("Cann't pause the domain")
    elif pre_vm_state == "transient":
        logging.info("Creating %s..." % vm_name)
        vm.undefine()
        if virsh.create(backup_xml.xml, **virsh_dargs).exit_status:
            backup_xml.define()
            raise exceptions.TestSkipError("Cann't create the domain")
        vm.wait_for_login().close()

    # Test.
    domid = vm.get_id()
    domuuid = vm.get_uuid()

    # Confirm how to reference a VM.
    if vm_ref == "name":
        vm_ref = vm_name
    elif vm_ref.find("invalid") != -1:
        vm_ref = params.get(vm_ref)
    elif vm_ref == "id":
        vm_ref = domid
    elif vm_ref == "hex_id":
        vm_ref = hex(int(domid))
    elif vm_ref == "uuid":
        vm_ref = domuuid
    else:
        vm_ref = ""

    try:
        device_source = os.path.join(data_dir.get_tmp_dir(), device_source_name)
        libvirt.create_local_disk("file", device_source, "1")

        # Get disk xml file.
        disk_params = {
            "type_name": "file",
            "device_type": device,
            "target_dev": device_target,
            "target_bus": "virtio",
            "source_file": device_source,
            "driver_name": "qemu",
            "driver_type": "raw",
        }
        disk_xml = libvirt.create_disk_xml(disk_params)

        # Attach the disk.
        ret = virsh.attach_device(vm_ref, disk_xml, flagstr=at_options, debug=True)
        libvirt.check_exit_status(ret, at_status_error)

        # Check if command take affect config file.
        if vm.is_paused():
            vm.resume()
            vm.wait_for_login().close()

        # Sleep a while for vm is stable
        time.sleep(3)
        if not ret.exit_status:
            check_result(device_source, device, device_target, at_options)

        # Detach the disk.
        if pre_vm_state == "paused":
            if not vm.pause():
                raise exceptions.TestFail("Cann't pause the domain")
        disk_xml = libvirt.create_disk_xml(disk_params)
        ret = virsh.detach_device(vm_ref, disk_xml, flagstr=dt_options, debug=True)
        libvirt.check_exit_status(ret, dt_status_error)

        # Check if command take affect config file.
        if vm.is_paused():
            vm.resume()
            vm.wait_for_login().close()

        # Sleep a while for vm is stable
        time.sleep(3)
        if not ret.exit_status:
            check_result(device_source, device, device_target, dt_options, False)

        # Try to start vm at last.
        if vm.is_dead():
            vm.start()
            vm.wait_for_login().close()

    finally:
        # Recover VM.
        if vm.is_alive():
            vm.destroy(gracefully=False)
        backup_xml.sync()

        if os.path.exists(device_source):
            os.remove(device_source)

#.........这里部分代码省略.........
    options = params.get("change_media_options")
    options_twice = params.get("change_media_options_twice", "")
    device_type = params.get("change_media_device_type", "cdrom")
    target_device = params.get("change_media_target_device", "hdc")
    init_iso_name = params.get("change_media_init_iso")
    old_iso_name = params.get("change_media_old_iso")
    new_iso_name = params.get("change_media_new_iso")
    virsh_dargs = {"debug": True, "ignore_status": True}

    if device_type not in ['cdrom', 'floppy']:
        raise exceptions.TestSkipError("Got a invalid device type:/n%s"
                                       % device_type)

    # Backup for recovery.
    vmxml_backup = vm_xml.VMXML.new_from_inactive_dumpxml(vm_name)

    old_iso = os.path.join(data_dir.get_tmp_dir(), old_iso_name)
    new_iso = os.path.join(data_dir.get_tmp_dir(), new_iso_name)

    if vm_ref == "name":
        vm_ref = vm_name

    if vm.is_alive():
        vm.destroy(gracefully=False)

    try:
        if not init_iso_name:
            init_iso = ""
        else:
            init_iso = os.path.join(data_dir.get_tmp_dir(),
                                    init_iso_name)

        # Prepare test files.
        libvirt.create_local_disk("iso", old_iso)
        libvirt.create_local_disk("iso", new_iso)

        # Check domain's disk device
        disk_blk = vm_xml.VMXML.get_disk_blk(vm_name)
        logging.info("disk_blk %s", disk_blk)
        if target_device not in disk_blk:
            if vm.is_alive():
                virsh.destroy(vm_name)
            logging.info("Adding device")
            libvirt.create_local_disk("iso", init_iso)
            disk_params = {"disk_type": "file", "device_type": device_type,
                           "driver_name": "qemu", "driver_type": "raw",
                           "target_bus": "ide", "readonly": "yes"}
            libvirt.attach_additional_device(vm_name, target_device,
                                             init_iso, disk_params)

        vmxml_for_test = vm_xml.VMXML.new_from_inactive_dumpxml(vm_name)
        # Turn VM into certain state.
        if pre_vm_state == "running":
            logging.info("Starting %s..." % vm_name)
            if vm.is_dead():
                vm.start()
                vm.wait_for_login().close()
        elif pre_vm_state == "shutoff":
            logging.info("Shuting down %s..." % vm_name)
            if vm.is_alive():
                vm.destroy(gracefully=False)
        elif pre_vm_state == "paused":
            logging.info("Pausing %s..." % vm_name)
            if vm.is_dead():
                vm.start()
                vm.wait_for_login().close()