Merge "Fix root disk not be detached after deleting lxc container"

nova/tests/virt/test_virt.py

@@ -137,3 +137,34 @@ class TestVirtDisk(test.NoDBTestCase):
                              ]
 
         self.assertEqual(self.executes, expected_commands)
+
+    def test_lxc_teardown_container_with_namespace_cleaned(self):
+
+        def proc_mounts(self, mount_point):
+            return None
+
+        self.stubs.Set(os.path, 'exists', lambda _: True)
+        self.stubs.Set(disk_api._DiskImage, '_device_for_path', proc_mounts)
+        expected_commands = []
+
+        disk_api.teardown_container('/mnt/loop/nopart', '/dev/loop0')
+        expected_commands += [
+                              ('losetup', '--detach', '/dev/loop0'),
+                             ]
+
+        disk_api.teardown_container('/mnt/loop/part', '/dev/loop0')
+        expected_commands += [
+                              ('losetup', '--detach', '/dev/loop0'),
+                             ]
+
+        disk_api.teardown_container('/mnt/nbd/nopart', '/dev/nbd15')
+        expected_commands += [
+                              ('qemu-nbd', '-d', '/dev/nbd15'),
+                             ]
+
+        disk_api.teardown_container('/mnt/nbd/part', '/dev/nbd15')
+        expected_commands += [
+                              ('qemu-nbd', '-d', '/dev/nbd15'),
+                             ]
+
+        self.assertEqual(self.executes, expected_commands)

nova/virt/disk/api.py

@@ -208,6 +208,8 @@ class _DiskImage(object):
         self.mount_dir = mount_dir
         self.use_cow = use_cow
 
+        self.device = None
+
         # Internal
         self._mkdir = False
         self._mounter = None
@@ -239,6 +241,7 @@ class _DiskImage(object):
 
         mount_name = os.path.basename(self.mount_dir or '')
         self._mkdir = mount_name.startswith(self.tmp_prefix)
+        self.device = self._mounter.device
 
     @property
     def errors(self):
@@ -344,6 +347,8 @@ def setup_container(image, container_dir, use_cow=False):
 
     It will mount the loopback image to the container directory in order
     to create the root filesystem for the container.
+
+    Returns path of image device which is mounted to the container directory.
     """
     img = _DiskImage(image=image, use_cow=use_cow, mount_dir=container_dir)
     if not img.mount():
@@ -352,9 +357,11 @@ def setup_container(image, container_dir, use_cow=False):
                   {"image": img, "target": container_dir,
                    "errors": img.errors})
         raise exception.NovaException(img.errors)
+    else:
+        return img.device
 
 
-def teardown_container(container_dir):
+def teardown_container(container_dir, container_root_device=None):
     """Teardown the container rootfs mounting once it is spawned.
 
     It will umount the container that is mounted,
@@ -363,6 +370,17 @@ def teardown_container(container_dir):
     try:
         img = _DiskImage(image=None, mount_dir=container_dir)
         img.teardown()
+
+        # Make sure container_root_device is released when teardown container.
+        if container_root_device:
+            if 'loop' in container_root_device:
+                LOG.debug(_("Release loop device %s"), container_root_device)
+                utils.execute('losetup', '--detach', container_root_device,
+                              run_as_root=True, attempts=3)
+            else:
+                LOG.debug(_('Release nbd device %s'), container_root_device)
+                utils.execute('qemu-nbd', '-d', container_root_device,
+                              run_as_root=True)
     except Exception as exn:
         LOG.exception(_('Failed to teardown container filesystem: %s'), exn)
 

nova/virt/libvirt/driver.py

@@ -930,6 +930,13 @@ class LibvirtDriver(driver.ComputeDriver):
                                       disk_dev)
 
         if destroy_disks:
+            #NOTE(GuanQiang): teardown lxc container to avoid resource leak
+            if CONF.libvirt_type == 'lxc':
+                inst_path = libvirt_utils.get_instance_path(instance)
+                container_dir = os.path.join(inst_path, 'rootfs')
+                container_root_device = instance.get('root_device_name')
+                disk.teardown_container(container_dir, container_root_device)
+
             self._delete_instance_files(instance)
 
             self._cleanup_lvm(instance)
@@ -3126,10 +3133,18 @@ class LibvirtDriver(driver.ComputeDriver):
             container_dir = os.path.join(inst_path, 'rootfs')
             fileutils.ensure_tree(container_dir)
             image = self.image_backend.image(instance, 'disk')
-            disk.setup_container(image.path,
+            container_root_device = disk.setup_container(image.path,
                                                 container_dir=container_dir,
                                                 use_cow=CONF.use_cow_images)
 
+            #Note(GuanQiang): save container root device name here, used for
+            #                 detaching the linked image device when deleting
+            #                 the lxc instance.
+            if container_root_device:
+                self.virtapi.instance_update(
+                    nova_context.get_admin_context(), instance['uuid'],
+                    {'root_device_name': container_root_device})
+
         if xml:
             try:
                 domain = self._conn.defineXML(xml)