Fix libvirt watchdog support

Using the flavor extra_specs property "hw_watchdog_action" was broken.
Scheduling of a new instance always failed with NoValidHostFound error
because of ComputeCapabilitiesFilter, which treated this property as a
host capability to be checked.

Commit f0ff4d5105 caused the problem.

To fix this watchdog_action property is put into 'hw:' scope, so
that it will be ignored by ComputeCapabilitiesFilter in scheduler and
handled in libvirt driver. The doc must be fixed accordingly.

Now driver accepts both 'hw_watchdog_action' and
'hw:watchdog_action', tests were edited for these cases.
Were added TODO items to delete the compat code in L release.

DocImpact
Closes-Bug: #1367344

Conflicts:
	nova/tests/virt/libvirt/test_driver.py

Change-Id: Ic5344ec34a130ee5a0ed2c7348af0b9d79e3508e
(cherry picked from commit 79bfb1bf34)

nova/tests/virt/libvirt/test_driver.py

@@ -2192,14 +2192,15 @@ class LibvirtConnTestCase(test.TestCase):
 
         self.assertEqual("none", cfg.devices[7].action)
 
-    def test_get_guest_config_with_watchdog_action_through_flavor(self):
+    def _test_get_guest_config_with_watchdog_action_flavor(self,
+            hw_watchdog_action="hw:watchdog_action"):
         self.flags(virt_type='kvm', group='libvirt')
 
         conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
 
         fake_flavor = objects.Flavor.get_by_id(
                 self.context, self.test_instance['instance_type_id'])
-        fake_flavor.extra_specs = {'hw_watchdog_action': 'none'}
+        fake_flavor.extra_specs = {hw_watchdog_action: 'none'}
 
         instance_ref = db.instance_create(self.context, self.test_instance)
 
@@ -2232,6 +2233,16 @@ class LibvirtConnTestCase(test.TestCase):
 
             self.assertEqual("none", cfg.devices[7].action)
 
+    def test_get_guest_config_with_watchdog_action_through_flavor(self):
+        self._test_get_guest_config_with_watchdog_action_flavor()
+
+    # TODO(pkholkin): the test accepting old property name 'hw_watchdog_action'
+    #                should be removed in L release
+    def test_get_guest_config_with_watchdog_action_through_flavor_no_scope(
+            self):
+        self._test_get_guest_config_with_watchdog_action_flavor(
+            hw_watchdog_action="hw_watchdog_action")
+
     def test_get_guest_config_with_watchdog_action_meta_overrides_flavor(self):
         self.flags(virt_type='kvm', group='libvirt')
 

nova/virt/libvirt/driver.py

@@ -4094,8 +4094,16 @@ class LibvirtDriver(driver.ComputeDriver):
                 raise exception.PciDeviceUnsupportedHypervisor(
                     type=CONF.libvirt.virt_type)
 
-        watchdog_action = flavor.extra_specs.get('hw_watchdog_action',
+        if 'hw_watchdog_action' in flavor.extra_specs:
-                                                 'disabled')
+            LOG.warn(_LW('Old property name "hw_watchdog_action" is now '
+                         'deprecated and will be removed in L release. '
+                         'Use updated property name '
+                         '"hw:watchdog_action" instead'))
+        # TODO(pkholkin): accepting old property name 'hw_watchdog_action'
+        #                should be removed in L release
+        watchdog_action = (flavor.extra_specs.get('hw_watchdog_action') or
+                           flavor.extra_specs.get('hw:watchdog_action')
+                           or 'disabled')
         if (image_meta is not None and
                 image_meta.get('properties', {}).get('hw_watchdog_action')):
             watchdog_action = image_meta['properties']['hw_watchdog_action']