bug 899767: fix vif-plugging with live migration

Expose vif_unplug method in virt layer, as the compute manager has to
explicitly call it on during live migration, so that network devices are
torn down even if the disk image is not.

Change-Id: Iae88c72f4fd2c7c097c23ef9e5f8fd392052f73e

nova/compute/manager.py

@@ -1735,6 +1735,12 @@ class ComputeManager(manager.SchedulerDependentManager):
         # must be deleted for preparing next block migration
         if block_migration:
             self.driver.destroy(instance_ref, network_info)
+        else:
+            # self.driver.destroy() usually performs  vif unplugging
+            # but we must do it explicitly here when block_migration
+            # is false, as the network devices at the source must be
+            # torn down
+            self.driver.unplug_vifs(instance_ref, network_info)
 
         LOG.info(_('Migrating %(i_name)s to %(dest)s finished successfully.')
                  % locals())

nova/tests/test_compute.py

@@ -1022,6 +1022,8 @@ class ComputeTestCase(BaseTestCase):
         rpc.call(c, db.queue_get_for(c, FLAGS.compute_topic, dest),
             {"method": "post_live_migration_at_destination",
              "args": {'instance_id': i_ref['id'], 'block_migration': False}})
+        self.mox.StubOutWithMock(self.compute.driver, 'unplug_vifs')
+        self.compute.driver.unplug_vifs(i_ref, [])
 
         # start test
         self.mox.ReplayAll()

nova/virt/driver.py

@@ -516,10 +516,14 @@ class ComputeDriver(object):
         raise NotImplementedError()
 
     def plug_vifs(self, instance, network_info):
-        """Plugs in VIFs to networks."""
+        """Plug VIFs into networks."""
         # TODO(Vek): Need to pass context in for access to auth_token
         raise NotImplementedError()
 
+    def unplug_vifs(self, instance, network_info):
+        """Unplug VIFs from networks."""
+        raise NotImplementedError()
+
     def update_host_status(self):
         """Refresh host stats"""
         raise NotImplementedError()

nova/virt/fake.py

@@ -94,7 +94,11 @@ class FakeConnection(driver.ComputeDriver):
         return info_list
 
     def plug_vifs(self, instance, network_info):
-        """Plugin VIFs into networks."""
+        """Plug VIFs into networks."""
+        pass
+
+    def unplug_vifs(self, instance, network_info):
+        """Unplug VIFs from networks."""
         pass
 
     def spawn(self, context, instance, image_meta,

nova/virt/hyperv.py

@@ -516,3 +516,11 @@ class HyperVConnection(driver.ComputeDriver):
     def set_host_enabled(self, host, enabled):
         """Sets the specified host's ability to accept new instances."""
         pass
+
+    def plug_vifs(self, instance, network_info):
+        """Plug VIFs into networks."""
+        pass
+
+    def unplug_vifs(self, instance, network_info):
+        """Unplug VIFs from networks."""
+        pass

nova/virt/libvirt/connection.py

@@ -290,10 +290,15 @@ class LibvirtConnection(driver.ComputeDriver):
         return infos
 
     def plug_vifs(self, instance, network_info):
-        """Plugin VIFs into networks."""
+        """Plug VIFs into networks."""
         for (network, mapping) in network_info:
             self.vif_driver.plug(instance, network, mapping)
 
+    def unplug_vifs(self, instance, network_info):
+        """Unplug VIFs from networks."""
+        for (network, mapping) in network_info:
+            self.vif_driver.unplug(instance, network, mapping)
+
     def destroy(self, instance, network_info, block_device_info=None,
                 cleanup=True):
         instance_name = instance['name']
@@ -350,8 +355,7 @@ class LibvirtConnection(driver.ComputeDriver):
                             locals())
                 raise
 
-        for (network, mapping) in network_info:
+        self.unplug_vifs(instance, network_info)
-            self.vif_driver.unplug(instance, network, mapping)
 
         def _wait_for_destroy():
             """Called at an interval until the VM is gone."""
@@ -545,6 +549,7 @@ class LibvirtConnection(driver.ComputeDriver):
         # better because we cannot ensure flushing dirty buffers
         # in the guest OS. But, in case of KVM, shutdown() does not work...
         self.destroy(instance, network_info, cleanup=False)
+        self.unplug_vifs(instance, network_info)
         self.plug_vifs(instance, network_info)
         self.firewall_driver.setup_basic_filtering(instance, network_info)
         self.firewall_driver.prepare_instance_filter(instance, network_info)

nova/virt/vmwareapi_conn.py

@@ -201,9 +201,13 @@ class VMWareESXConnection(driver.ComputeDriver):
         pass
 
     def plug_vifs(self, instance, network_info):
-        """Plugs in VIFs to networks."""
+        """Plug VIFs into networks."""
         self._vmops.plug_vifs(instance, network_info)
 
+    def unplug_vifs(self, instance, network_info):
+        """Unplug VIFs from networks."""
+        self._vmops.unplug_vifs(instance, network_info)
+
 
 class VMWareAPISession(object):
     """

nova/virt/xenapi/vmops.py

@@ -1139,9 +1139,7 @@ class VMOps(object):
             self._destroy_kernel_ramdisk(instance, vm_ref)
         self._destroy_vm(instance, vm_ref)
 
-        if network_info:
+        self.unplug_vifs(instance, network_info)
-            for (network, mapping) in network_info:
-                self.vif_driver.unplug(instance, network, mapping)
 
     def pause(self, instance):
         """Pause VM instance."""
@@ -1459,6 +1457,11 @@ class VMOps(object):
         for (network, mapping) in network_info:
             self.vif_driver.plug(self._session, instance, network, mapping)
 
+    def unplug_vifs(self, instance, network_info):
+        if network_info:
+            for (network, mapping) in network_info:
+                self.vif_driver.unplug(instance, network, mapping)
+
     def reset_network(self, instance, vm_ref=None):
         """Creates uuid arg to pass to make_agent_call and calls it."""
         if not vm_ref:

nova/virt/xenapi_conn.py

@@ -297,8 +297,13 @@ class XenAPIConnection(driver.ComputeDriver):
         self._vmops.inject_network_info(instance, network_info)
 
     def plug_vifs(self, instance_ref, network_info):
+        """Plug VIFs into networks."""
         self._vmops.plug_vifs(instance_ref, network_info)
 
+    def unplug_vifs(self, instance_ref, network_info):
+        """Unplug VIFs from networks."""
+        self._vmops.unplug_vifs(instance_ref, network_info)
+
     def get_info(self, instance_name):
         """Return data about VM instance"""
         return self._vmops.get_info(instance_name)