diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py
index 71e3bf908e4..38302078cc7 100644
--- a/nova/tests/unit/virt/libvirt/test_driver.py
+++ b/nova/tests/unit/virt/libvirt/test_driver.py
@@ -5504,6 +5504,52 @@ def _test_get_serial_ports_from_guest(self, mode, mock_get_xml_desc,
guest = libvirt_guest.Guest(FakeVirtDomain())
return drvr._get_serial_ports_from_guest(guest, mode=mode)
+ def test_get_scsi_controller_next_unit_from_guest(self):
+ xml = """
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ """
+ self._test_get_scsi_controller_next_unit_from_guest(xml, 2)
+
+ def test_get_scsi_controller_next_unit_from_guest_no_scsi(self):
+ xml = """
+
+
+
+
+
+
+
+
+
+
+ """
+ self._test_get_scsi_controller_next_unit_from_guest(xml, 0)
+
+ @mock.patch.object(libvirt_guest.Guest, "get_xml_desc")
+ def _test_get_scsi_controller_next_unit_from_guest(self, xml,
+ expect_num,
+ mock_get_xml_desc):
+ mock_get_xml_desc.return_value = xml
+
+ drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
+ guest = libvirt_guest.Guest(FakeVirtDomain())
+ i = drvr._get_scsi_controller_next_unit(guest)
+ self.assertEqual(expect_num, i)
+
def test_get_guest_config_with_type_xen(self):
self.flags(enabled=True, group='vnc')
self.flags(virt_type='xen',
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index 9ddf6918ce2..3067e93efa6 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -1402,16 +1402,16 @@ def _get_serial_ports_from_guest(self, guest, mode=None):
for source in tcp_devices:
yield (source.get("host"), int(source.get("service")))
- def _get_scsi_controller_max_unit(self, guest):
+ def _get_scsi_controller_next_unit(self, guest):
"""Returns the max disk unit used by scsi controller"""
xml = guest.get_xml_desc()
tree = etree.fromstring(xml)
- addrs = "./devices/disk[@device='disk']/address[@type='drive']"
+ addrs = "./devices/disk[target/@bus='scsi']/address[@type='drive']"
ret = []
- for obj in tree.findall(addrs):
+ for obj in tree.xpath(addrs):
ret.append(int(obj.get('unit', 0)))
- return max(ret)
+ return max(ret) + 1 if ret else 0
def _cleanup_rbd(self, instance):
# NOTE(nic): On revert_resize, the cleanup steps for the root
@@ -1725,7 +1725,7 @@ def attach_volume(self, context, connection_info, instance, mountpoint,
disk_info = blockinfo.get_info_from_bdm(
instance, CONF.libvirt.virt_type, instance.image_meta, bdm)
if disk_info['bus'] == 'scsi':
- disk_info['unit'] = self._get_scsi_controller_max_unit(guest) + 1
+ disk_info['unit'] = self._get_scsi_controller_next_unit(guest)
conf = self._get_volume_config(connection_info, disk_info)