Notify nova when ports are ready

The following patch adds a callback from neutron to nova that notifies nova
when a port for an instance is *ready to be used*. After nova receives this
event it will then start the instance in a hope that when it comes up
its networking should be in working order.

NOTE: *ready to be used* currently means that a plugin changes the status
in the db associated with a port from:
NO_VALUE/PORT_STATUS_DOWN/PORT_STATUS_ACTIVE to ACTIVE/ERROR.

Neutron will then signal nova: network_vif_plugged:<status> where status
will either be 'completed' or 'failed' given the neutron port status.

Neutron also notifies nova when a port goes from status:
PORT_STATUS_ACTIVE to PORT_STATUS_DOWN and sends nova a network_vif_unplugged
event.

Currently this patch breaks multiregion support (i.e previously you could
back multiple nova regions by one neutron server) though now since neutron
needs to notify nova we'll need to add a way to determine which region a
given port is in.

For now the work around for this would be to set: notify_nova_port_active=False
in neutron to prevent neutron from sending the notification and setting:
vif_plugging_is_fatal=False in nova.conf. Doing this will keep the current
interaction where an instance will be booted without waiting for the network
to be ready.

DocImpact

implements blueprint: nova-event-callback

Change-Id: I4177124485b986706fcf8e73b928024b5d82b822

etc/neutron.conf

@@ -291,6 +291,34 @@ notification_driver = neutron.openstack.common.notifier.rpc_notifier
 # ssl_ca_file = /path/to/cafile
 # ======== end of WSGI parameters related to the API server ==========
 
+
+# ======== neutron nova interactions ==========
+# Send notification to nova when port status is active.
+# notify_nova_on_port_status_changes = True
+
+# URL for connection to nova (Only supports one nova region currently).
+# nova_url = http://127.0.0.1:8774
+
+# Name of nova region to use. Useful if keystone manages more than one region
+# nova_region_name =
+
+# Username for connection to nova in admin context
+# nova_admin_username =
+
+# The uuid of the admin nova tenant
+# nova_admin_tenant_id =
+
+# Password for connection to nova in admin context.
+# nova_admin_password =
+
+# Authorization URL for connection to nova in admin context.
+# nova_admin_auth_url =
+
+# Number of seconds between sending events to nova if there are any events to send
+# send_events_interval = 2
+
+# ======== end of neutron nova interactions ==========
+
 [quotas]
 # Default driver to use for quota checks
 # quota_driver = neutron.db.quota_db.DbQuotaDriver

neutron/common/config.py

@@ -81,6 +81,28 @@ core_opts = [
                help=_("The hostname Neutron is running on")),
     cfg.BoolOpt('force_gateway_on_subnet', default=False,
                 help=_("Ensure that configured gateway is on subnet")),
+    cfg.BoolOpt('notify_nova_on_port_status_changes', default=True,
+                help=_("Send notification to nova when port status changes")),
+    cfg.StrOpt('nova_url',
+               default='http://127.0.0.1:8774',
+               help=_('URL for connection to nova')),
+    cfg.StrOpt('nova_admin_username',
+               help=_('Username for connecting to nova in admin context')),
+    cfg.StrOpt('nova_admin_password',
+               help=_('Password for connection to nova in admin context'),
+               secret=True),
+    cfg.StrOpt('nova_admin_tenant_id',
+               help=_('The uuid of the admin nova tenant')),
+    cfg.StrOpt('nova_admin_auth_url',
+               default='http://localhost:5000/v2.0',
+               help=_('Authorization URL for connecting to nova in admin '
+                      'context')),
+    cfg.StrOpt('nova_region_name',
+               help=_('Name of nova region to use. Useful if keystone manages'
+                      ' more than one region.')),
+    cfg.IntOpt('send_events_interval', default=2,
+               help=_('Number of seconds between sending events to nova if '
+                      'there are any events to send.')),
 ]
 
 core_cli_opts = [

neutron/db/db_base_plugin_v2.py

@@ -19,6 +19,7 @@ import random
 
 import netaddr
 from oslo.config import cfg
+from sqlalchemy import event
 from sqlalchemy import orm
 from sqlalchemy.orm import exc
 
@@ -29,6 +30,7 @@ from neutron.db import api as db
 from neutron.db import models_v2
 from neutron.db import sqlalchemyutils
 from neutron import neutron_plugin_base_v2
+from neutron.notifiers import nova
 from neutron.openstack.common import excutils
 from neutron.openstack.common import log as logging
 from neutron.openstack.common import uuidutils
@@ -221,6 +223,16 @@ class NeutronDbPluginV2(neutron_plugin_base_v2.NeutronPluginBaseV2,
 
     def __init__(self):
         db.configure_db()
+        if cfg.CONF.notify_nova_on_port_status_changes:
+            # NOTE(arosen) These event listners are here to hook into when
+            # port status changes and notify nova about their change.
+            self.nova_notifier = nova.Notifier()
+            event.listen(models_v2.Port, 'after_insert',
+                         self.nova_notifier.send_port_status)
+            event.listen(models_v2.Port, 'after_update',
+                         self.nova_notifier.send_port_status)
+            event.listen(models_v2.Port.status, 'set',
+                         self.nova_notifier.record_port_status_changed)
 
     @classmethod
     def register_dict_extend_funcs(cls, resource, funcs):

neutron/db/models_v2.py

@@ -130,6 +130,24 @@ class Port(model_base.BASEV2, HasId, HasTenant):
     device_id = sa.Column(sa.String(255), nullable=False)
     device_owner = sa.Column(sa.String(255), nullable=False)
 
+    def __init__(self, id=None, tenant_id=None, name=None, network_id=None,
+                 mac_address=None, admin_state_up=None, status=None,
+                 device_id=None, device_owner=None, fixed_ips=None):
+        self.id = id
+        self.tenant_id = tenant_id
+        self.name = name
+        self.network_id = network_id
+        self.mac_address = mac_address
+        self.admin_state_up = admin_state_up
+        self.device_owner = device_owner
+        self.device_id = device_id
+        # Since this is a relationship only set it if one is passed in.
+        if fixed_ips:
+            self.fixed_ips = fixed_ips
+
+        # NOTE(arosen): status must be set last as an event is triggered on!
+        self.status = status
+
 
 class DNSNameServer(model_base.BASEV2):
     """Internal representation of a DNS nameserver."""

neutron/notifiers/nova.py

@@ -0,0 +1,146 @@
+# Copyright (c) 2014 OpenStack Foundation.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import novaclient.v1_1.client as nclient
+from novaclient.v1_1.contrib import server_external_events
+from oslo.config import cfg
+from sqlalchemy.orm import attributes as sql_attr
+
+from neutron.common import constants
+from neutron.openstack.common import log as logging
+from neutron.openstack.common import loopingcall
+
+
+LOG = logging.getLogger(__name__)
+
+VIF_UNPLUGGED = 'network-vif-unplugged'
+VIF_PLUGGED = 'network-vif-plugged'
+NEUTRON_NOVA_EVENT_STATUS_MAP = {constants.PORT_STATUS_ACTIVE: 'completed',
+                                 constants.PORT_STATUS_ERROR: 'failed',
+                                 constants.PORT_STATUS_DOWN: 'completed'}
+
+
+class Notifier(object):
+
+    def __init__(self):
+        # TODO(arosen): we need to cache the endpoints and figure out
+        # how to deal with different regions here....
+        bypass_url = "%s/%s" % (cfg.CONF.nova_url,
+                                cfg.CONF.nova_admin_tenant_id)
+        self.nclient = nclient.Client(
+            username=cfg.CONF.nova_admin_username,
+            api_key=cfg.CONF.nova_admin_password,
+            project_id=None,
+            tenant_id=cfg.CONF.nova_admin_tenant_id,
+            auth_url=cfg.CONF.nova_admin_auth_url,
+            bypass_url=bypass_url,
+            region_name=cfg.CONF.nova_region_name,
+            extensions=[server_external_events])
+        self.pending_events = []
+        event_sender = loopingcall.FixedIntervalLoopingCall(self.send_events)
+        event_sender.start(interval=cfg.CONF.send_events_interval)
+
+    def record_port_status_changed(self, port, current_port_status,
+                                   previous_port_status, initiator):
+        """Determine if nova needs to be notified due to port status change.
+        """
+        # clear out previous _notify_event
+        port._notify_event = None
+        # If there is no device_id set there is nothing we can do here.
+        if not port.device_id:
+            LOG.debug(_("device_id is not set on port yet."))
+            return
+
+        if not port.id:
+            LOG.warning(_("Port ID not set! Nova will not be notified of "
+                          "port status change."))
+            return
+
+        # We only want to notify about nova ports.
+        if (not port.device_owner or
+            not port.device_owner.startswith('compute:')):
+            return
+
+        # We notify nova when a vif is unplugged which only occurs when
+        # the status goes from ACTIVE to DOWN.
+        if (previous_port_status == constants.PORT_STATUS_ACTIVE and
+            current_port_status == constants.PORT_STATUS_DOWN):
+            event_name = VIF_UNPLUGGED
+
+        # We only notify nova when a vif is plugged which only occurs
+        # when the status goes from:
+        # NO_VALUE/DOWN/BUILD -> ACTIVE/ERROR.
+        elif (previous_port_status in [sql_attr.NO_VALUE,
+                                       constants.PORT_STATUS_DOWN,
+                                       constants.PORT_STATUS_BUILD]
+              and current_port_status in [constants.PORT_STATUS_ACTIVE,
+                                          constants.PORT_STATUS_ERROR]):
+            event_name = VIF_PLUGGED
+        # All the remaining state transitions are of no interest to nova
+        else:
+            LOG.debug(_("Ignoring state change previous_port_status: "
+                        "%(pre_status)s current_port_status: %(cur_status)s"
+                        " port_id %(id)s") %
+                      {'pre_status': previous_port_status,
+                       'cur_status': current_port_status,
+                       'id': port.id})
+            return
+
+        port._notify_event = (
+            {'server_uuid': port.device_id,
+             'name': event_name,
+             'status': NEUTRON_NOVA_EVENT_STATUS_MAP.get(current_port_status),
+             'tag': port.id})
+
+    def send_port_status(self, mapper, connection, port):
+        event = getattr(port, "_notify_event", None)
+        if event:
+            self.pending_events.append(event)
+        port._notify_event = None
+
+    def send_events(self):
+        batched_events = []
+        for event in range(len(self.pending_events)):
+            batched_events.append(self.pending_events.pop())
+
+        if not batched_events:
+            return
+
+        LOG.debug(_("Sending events: %s"), batched_events)
+        try:
+            response = self.nclient.server_external_events.create(
+                batched_events)
+        except Exception:
+            LOG.exception(_("Failed to notify nova on events: %s"),
+                          batched_events)
+        else:
+            if not isinstance(response, list):
+                LOG.error(_("Error response returned from nova: %s"),
+                          response)
+                return
+            response_error = False
+            for event in response:
+                try:
+                    status = event['status']
+                except KeyError:
+                    response_error = True
+                if status == 'failed':
+                    LOG.warning(_("Nova event: %s returned with failed "
+                                  "status"), event)
+                else:
+                    LOG.info(_("Nova event response: %s"), event)
+            if response_error:
+                LOG.error(_("Error response returned from nova: %s"),
+                          response)

neutron/tests/unit/notifiers/test_notifiers_nova.py

@@ -0,0 +1,104 @@
+# Copyright 2014 OpenStack Foundation
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+from sqlalchemy.orm import attributes as sql_attr
+
+from neutron.common import constants
+from neutron.db import models_v2
+from neutron.notifiers import nova
+from neutron.tests import base
+
+
+class TestNovaNotify(base.BaseTestCase):
+    def setUp(self, plugin=None):
+        super(TestNovaNotify, self).setUp()
+
+        self.nova_notifier = nova.Notifier()
+
+    def test_notify_port_status_all_values(self):
+        states = [constants.PORT_STATUS_ACTIVE, constants.PORT_STATUS_DOWN,
+                  constants.PORT_STATUS_ERROR, constants.PORT_STATUS_BUILD,
+                  sql_attr.NO_VALUE]
+        # test all combinations
+        for previous_port_status in states:
+            for current_port_status in states:
+                port = models_v2.Port(id='port-uuid', device_id='device-uuid',
+                                      device_owner="compute:",
+                                      status=current_port_status)
+                self._record_port_status_changed_helper(current_port_status,
+                                                        previous_port_status,
+                                                        port)
+
+    def test_port_without_device_owner_no_notify(self):
+        port = models_v2.Port(id='port-uuid', device_id='device-uuid',
+                              status=constants.PORT_STATUS_ACTIVE)
+        self._record_port_status_changed_helper(constants.PORT_STATUS_ACTIVE,
+                                                sql_attr.NO_VALUE,
+                                                port)
+
+    def test_port_without_device_id_no_notify(self):
+        port = models_v2.Port(id='port-uuid', device_owner="network:dhcp",
+                              status=constants.PORT_STATUS_ACTIVE)
+        self._record_port_status_changed_helper(constants.PORT_STATUS_ACTIVE,
+                                                sql_attr.NO_VALUE,
+                                                port)
+
+    def test_port_without_id_no_notify(self):
+        port = models_v2.Port(device_id='device-uuid',
+                              device_owner="compute:",
+                              status=constants.PORT_STATUS_ACTIVE)
+        self._record_port_status_changed_helper(constants.PORT_STATUS_ACTIVE,
+                                                sql_attr.NO_VALUE,
+                                                port)
+
+    def test_non_compute_instances_no_notify(self):
+        port = models_v2.Port(id='port-uuid', device_id='device-uuid',
+                              device_owner="network:dhcp",
+                              status=constants.PORT_STATUS_ACTIVE)
+        self._record_port_status_changed_helper(constants.PORT_STATUS_ACTIVE,
+                                                sql_attr.NO_VALUE,
+                                                port)
+
+    def _record_port_status_changed_helper(self, current_port_status,
+                                           previous_port_status, port):
+
+        if not (port.device_id and port.id and port.device_owner and
+                port.device_owner.startswith('compute:')):
+            return
+
+        if (previous_port_status == constants.PORT_STATUS_ACTIVE and
+                current_port_status == constants.PORT_STATUS_DOWN):
+            event_name = nova.VIF_UNPLUGGED
+
+        elif (previous_port_status in [sql_attr.NO_VALUE,
+                                       constants.PORT_STATUS_DOWN,
+                                       constants.PORT_STATUS_BUILD]
+              and current_port_status in [constants.PORT_STATUS_ACTIVE,
+                                          constants.PORT_STATUS_ERROR]):
+            event_name = nova.VIF_PLUGGED
+
+        else:
+            return
+
+        status = nova.NEUTRON_NOVA_EVENT_STATUS_MAP.get(current_port_status)
+        self.nova_notifier.record_port_status_changed(port,
+                                                      current_port_status,
+                                                      previous_port_status,
+                                                      None)
+
+        event = {'server_uuid': 'device-uuid', 'status': status,
+                 'name': event_name, 'tag': 'port-uuid'}
+        self.assertEqual(event, port._notify_event)

neutron/tests/unit/test_db_plugin.py

@@ -77,8 +77,9 @@ class NeutronDbPluginV2TestCase(testlib_api.WebTestCase):
 
     def setUp(self, plugin=None, service_plugins=None,
               ext_mgr=None):
-        super(NeutronDbPluginV2TestCase, self).setUp()
 
+        super(NeutronDbPluginV2TestCase, self).setUp()
+        cfg.CONF.set_override('notify_nova_on_port_status_changes', False)
         # Make sure at each test according extensions for the plugin is loaded
         PluginAwareExtensionManager._instance = None
         # Save the attributes map in case the plugin will alter it