Make xenapi capabilities['enabled'] use service enabled

filters.compute_filter is enabled by default along with libvirt, but the
capabilities['enabled'] section of it is only supported by XenAPI.
This used to work by adding a parameter to capabilities, but since
the capabilities RPC is being removed, use conductor.service_update to tell
the scheduler which host is disabled.

service_update is already the way to tell the scheduler about other
disabled hosts, so to keep backwards compatibility keep host_enabled but
use service_update underneath.

Part of bp no-compute-fanout-to-scheduler

Change-Id: Ica1919cfe9a2402b2107c557c10d47e01a6c430b

nova/scheduler/filters/compute_filter.py

@@ -36,7 +36,6 @@ class ComputeFilter(filters.BaseHostFilter):
 
     def host_passes(self, host_state, filter_properties):
         """Returns True for only active compute nodes."""
-        capabilities = host_state.capabilities
         service = host_state.service
 
         alive = self.servicegroup_api.service_is_up(service)
@@ -44,8 +43,4 @@ class ComputeFilter(filters.BaseHostFilter):
             LOG.debug(_("%(host_state)s is disabled or has not been "
                     "heard from in a while"), {'host_state': host_state})
             return False
-        if not capabilities.get("enabled", True):
-            LOG.debug(_("%(host_state)s is disabled via capabilities"),
-                    {'host_state': host_state})
-            return False
         return True

nova/tests/scheduler/test_host_filters.py

@@ -671,17 +671,6 @@ class HostFiltersTestCase(test.NoDBTestCase):
                  'service': service})
         self.assertFalse(filt_cls.host_passes(host, filter_properties))
 
-    def test_compute_filter_fails_on_capability_disabled(self):
-        self._stub_service_is_up(True)
-        filt_cls = self.class_map['ComputeFilter']()
-        filter_properties = {'instance_type': {'memory_mb': 1024}}
-        capabilities = {'enabled': False}
-        service = {'disabled': False}
-        host = fakes.FakeHostState('host1', 'node1',
-                {'free_ram_mb': 1024, 'capabilities': capabilities,
-                 'service': service})
-        self.assertFalse(filt_cls.host_passes(host, filter_properties))
-
     def test_image_properties_filter_passes_same_inst_props(self):
         self._stub_service_is_up(True)
         filt_cls = self.class_map['ImagePropertiesFilter']()

nova/tests/virt/xenapi/test_xenapi.py

@@ -1959,6 +1959,8 @@ class XenAPIHostTestCase(stubs.XenAPITestBase):
         self.flags(xenapi_connection_url='test_url',
                    xenapi_connection_password='test_pass')
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
+        self.context = context.get_admin_context()
+        self.flags(use_local=True, group='conductor')
         self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
 
     def test_host_state(self):
@@ -2004,10 +2006,18 @@ class XenAPIHostTestCase(stubs.XenAPITestBase):
                                False, 'off_maintenance')
 
     def test_set_enable_host_enable(self):
+        values = _create_service_entries(self.context, values={'nova':
+            ['host']})
         self._test_host_action(self.conn.set_host_enabled, True, 'enabled')
+        service = db.service_get_by_args(self.context, 'host', 'nova-compute')
+        self.assertEquals(service.disabled, False)
 
     def test_set_enable_host_disable(self):
+        values = _create_service_entries(self.context, values={'nova':
+            ['host']})
         self._test_host_action(self.conn.set_host_enabled, False, 'disabled')
+        service = db.service_get_by_args(self.context, 'host', 'nova-compute')
+        self.assertEquals(service.disabled, True)
 
     def test_get_host_uptime(self):
         result = self.conn.get_host_uptime('host')

nova/virt/xenapi/host.py

@@ -21,6 +21,7 @@ Management class for host-related functions (start, reboot, etc).
 
 from nova.compute import task_states
 from nova.compute import vm_states
+from nova import conductor
 from nova import context
 from nova import exception
 from nova.objects import instance as instance_obj
@@ -40,6 +41,7 @@ class Host(object):
     def __init__(self, session, virtapi):
         self._session = session
         self._virtapi = virtapi
+        self._conductor_api = conductor.API()
 
     def host_power_action(self, _host, action):
         """Reboots or shuts down the host."""
@@ -112,8 +114,23 @@ class Host(object):
             raise exception.NoValidHost(reason='Unable to find suitable '
                                                    'host for VMs evacuation')
 
-    def set_host_enabled(self, _host, enabled):
+    def set_host_enabled(self, host, enabled):
         """Sets the specified host's ability to accept new instances."""
+        # Since capabilities are gone, use service table to disable a node
+        # in scheduler
+        status = {'disabled': not enabled,
+                'disabled_reason': 'set by xenapi host_state'
+                }
+        cntxt = context.get_admin_context()
+        service = self._conductor_api.service_get_by_args(
+                cntxt,
+                host,
+                'nova-compute')
+        self._conductor_api.service_update(
+                cntxt,
+                service,
+                status)
+
         args = {"enabled": jsonutils.dumps(enabled)}
         response = call_xenhost(self._session, "set_host_enabled", args)
         return response.get("status", response)