Implement interface attach/detach in ironic virt driver

This patch implements attach_interface, detach_interface
methods in Ironic virt driver.

Implements: blueprint ironic-hotplug-interfaces
Co-Authored-By: Vladyslav Drok <vdrok@mirantis.com>
Depends-On: Idc9dc37b11950e3aa2864a0a90d6ec2e307926a3
Change-Id: I48c4706b3eb6e0a5105e463236870921d55dbd93

nova/tests/unit/virt/ironic/test_driver.py

@@ -129,11 +129,6 @@ class IronicDriverTestCase(test.NoDBTestCase):
                              'supports_migrate_to_same_host'],
                          'Driver capabilities for '
                          '\'supports_migrate_to_same_host\' is invalid')
-        self.assertFalse(self.driver.capabilities[
-                            'supports_attach_interface'],
-                         'Driver capabilities for '
-                         '\'supports_attach_interface\' '
-                         'is invalid')
 
     def test__get_hypervisor_type(self):
         self.assertEqual('ironic', self.driver._get_hypervisor_type())
@@ -1724,6 +1719,18 @@ class IronicDriverTestCase(test.NoDBTestCase):
         self.driver.unplug_vifs(instance, network_info)
         self.assertFalse(mock_vdet.called)
 
+    @mock.patch.object(ironic_driver.IronicDriver, 'plug_vifs')
+    def test_attach_interface(self, mock_pv):
+        self.driver.attach_interface('fake_context', 'fake_instance',
+                                     'fake_image_meta', 'fake_vif')
+        mock_pv.assert_called_once_with('fake_instance', ['fake_vif'])
+
+    @mock.patch.object(ironic_driver.IronicDriver, 'unplug_vifs')
+    def test_detach_interface(self, mock_uv):
+        self.driver.detach_interface('fake_context', 'fake_instance',
+                                     'fake_vif')
+        mock_uv.assert_called_once_with('fake_instance', ['fake_vif'])
+
     @mock.patch.object(firewall.NoopFirewallDriver, 'unfilter_instance',
                        create=True)
     def test_unfilter_instance(self, mock_ui):

nova/virt/ironic/driver.py

@@ -129,7 +129,7 @@ class IronicDriver(virt_driver.ComputeDriver):
     capabilities = {"has_imagecache": False,
                     "supports_recreate": False,
                     "supports_migrate_to_same_host": False,
-                    "supports_attach_interface": False
+                    "supports_attach_interface": True
                     }
 
     def __init__(self, virtapi, read_only=False):
@@ -1302,6 +1302,44 @@ class IronicDriver(virt_driver.ComputeDriver):
         node = self._get_node(instance.node)
         self._unplug_vifs(node, instance, network_info)
 
+    def attach_interface(self, context, instance, image_meta, vif):
+        """Use hotplug to add a network interface to a running instance.
+        The counter action to this is :func:`detach_interface`.
+
+        :param context: The request context.
+        :param nova.objects.instance.Instance instance:
+            The instance which will get an additional network interface.
+        :param nova.objects.ImageMeta image_meta:
+            The metadata of the image of the instance.
+        :param nova.network.model.VIF vif:
+            The object which has the information about the interface to attach.
+        :raise nova.exception.NovaException: If the attach fails.
+        :returns: None
+        """
+        # NOTE(vdrok): instance info cache gets updated by the network-changed
+        # event from neutron or by _heal_instance_info_cache periodic task. In
+        # both cases, this is done asynchronously, so the cache may not be up
+        # to date immediately after attachment.
+        self.plug_vifs(instance, [vif])
+
+    def detach_interface(self, context, instance, vif):
+        """Use hotunplug to remove a network interface from a running instance.
+        The counter action to this is :func:`attach_interface`.
+
+        :param context: The request context.
+        :param nova.objects.instance.Instance instance:
+            The instance which gets a network interface removed.
+        :param nova.network.model.VIF vif:
+            The object which has the information about the interface to detach.
+        :raise nova.exception.NovaException: If the detach fails.
+        :returns: None
+        """
+        # NOTE(vdrok): instance info cache gets updated by the network-changed
+        # event from neutron or by _heal_instance_info_cache periodic task. In
+        # both cases, this is done asynchronously, so the cache may not be up
+        # to date immediately after detachment.
+        self.unplug_vifs(instance, [vif])
+
     def rebuild(self, context, instance, image_meta, injected_files,
                 admin_password, bdms, detach_block_devices,
                 attach_block_devices, network_info=None,

releasenotes/notes/add-interface-attach-detach-support-in-ironic-cb2bf11f3875350a.yaml

@@ -0,0 +1,18 @@
+---
+features:
+  - |
+    Adds interface attach/detach support to baremetal nodes using ironic virt
+    driver. Note that the instance info cache update relies on getting a
+    ``network-changed`` event from neutron, or on the periodic task healing
+    the instance info cache, both of which are asynchronous. This means that
+    nova's cached network information (which is what is sent e.g. in the
+    ``GET /servers`` responses) may not be up to date immediately after the
+    attachment or detachment.
+upgrade:
+  - |
+    Interface attachment/detachment for ironic virt driver was implemented in
+    in-tree network interfaces in ironic version 8.0, and this release is
+    required for nova's interface attachment feature to work. Prior to that
+    release, calling VIF attach on an active ironic node using in-tree network
+    interfaces would be basically a noop. It should not be an issue during the
+    upgrade though, as it is required to upgrade ironic before nova.