diff --git a/neutron/agent/l3/ha_router.py b/neutron/agent/l3/ha_router.py
index b7d7031fd7c..68324bf3ef1 100644
--- a/neutron/agent/l3/ha_router.py
+++ b/neutron/agent/l3/ha_router.py
@@ -385,7 +385,9 @@ def delete(self, agent):
     def process(self, agent):
         super(HaRouter, self).process(agent)
 
-        if self.ha_port:
+        self.ha_port = self.router.get(n_consts.HA_INTERFACE_KEY)
+        if (self.ha_port and
+                self.ha_port['status'] == n_consts.PORT_STATUS_ACTIVE):
             self.enable_keepalived()
 
     @common_utils.synchronized('enable_radvd')
diff --git a/neutron/db/l3_hascheduler_db.py b/neutron/db/l3_hascheduler_db.py
index 7acb1c80f72..96dd9a178c4 100644
--- a/neutron/db/l3_hascheduler_db.py
+++ b/neutron/db/l3_hascheduler_db.py
@@ -12,13 +12,20 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from neutron_lib import constants
 from sqlalchemy import func
 from sqlalchemy import sql
 
+from neutron.callbacks import events
+from neutron.callbacks import registry
+from neutron.callbacks import resources
 from neutron.db import agents_db
 from neutron.db import l3_agentschedulers_db as l3_sch_db
 from neutron.db import l3_attrs_db
 from neutron.db import l3_db
+from neutron.extensions import portbindings
+from neutron import manager
+from neutron.plugins.common import constants as service_constants
 
 
 class L3_HA_scheduler_db_mixin(l3_sch_db.AZL3AgentSchedulerDbMixin):
@@ -81,3 +88,25 @@ def list_l3_agents_hosting_router(self, context, router_id):
                 bindings = [(binding.l3_agent, None) for binding in bindings]
 
         return self._get_agents_dict_for_router(bindings)
+
+
+def _notify_l3_agent_ha_port_update(resource, event, trigger, **kwargs):
+    port_db = kwargs.get('port')
+    context = kwargs.get('context')
+    core_plugin = manager.NeutronManager.get_plugin()
+    new_port = core_plugin._make_port_dict(port_db)
+    host = new_port.get(portbindings.HOST_ID)
+
+    if new_port and host:
+        new_device_owner = new_port.get('device_owner', '')
+        if (new_device_owner == constants.DEVICE_OWNER_ROUTER_HA_INTF and
+            new_port['status'] == constants.PORT_STATUS_ACTIVE):
+            l3plugin = manager.NeutronManager.get_service_plugins().get(
+                service_constants.L3_ROUTER_NAT)
+            l3plugin.l3_rpc_notifier.routers_updated_on_host(
+                context, [new_port['device_id']], host)
+
+
+def subscribe():
+    registry.subscribe(
+        _notify_l3_agent_ha_port_update, resources.PORT, events.AFTER_UPDATE)
diff --git a/neutron/services/l3_router/l3_router_plugin.py b/neutron/services/l3_router/l3_router_plugin.py
index 70fcdce04f8..1cb85fe6930 100644
--- a/neutron/services/l3_router/l3_router_plugin.py
+++ b/neutron/services/l3_router/l3_router_plugin.py
@@ -30,6 +30,7 @@
 from neutron.db import l3_dvrscheduler_db
 from neutron.db import l3_gwmode_db
 from neutron.db import l3_hamode_db
+from neutron.db import l3_hascheduler_db
 from neutron.plugins.common import constants
 from neutron.quota import resource_registry
 from neutron.services import service_base
@@ -65,6 +66,8 @@ def __init__(self):
         super(L3RouterPlugin, self).__init__()
         if 'dvr' in self.supported_extension_aliases:
             l3_dvrscheduler_db.subscribe()
+        if 'l3-ha' in self.supported_extension_aliases:
+            l3_hascheduler_db.subscribe()
         l3_db.subscribe()
         self.start_rpc_listeners()
 
diff --git a/neutron/tests/functional/agent/l3/test_ha_router.py b/neutron/tests/functional/agent/l3/test_ha_router.py
index fd134af7324..454be2ebe14 100644
--- a/neutron/tests/functional/agent/l3/test_ha_router.py
+++ b/neutron/tests/functional/agent/l3/test_ha_router.py
@@ -256,6 +256,18 @@ def test_removing_floatingip_immediately(self):
         # call the configure_fip_addresses directly here
         router.configure_fip_addresses(interface_name)
 
+    def test_ha_port_status_update(self):
+        router_info = self.generate_router_info(enable_ha=True)
+        router_info[l3_constants.HA_INTERFACE_KEY]['status'] = (
+            l3_constants.PORT_STATUS_DOWN)
+        router1 = self.manage_router(self.agent, router_info)
+        utils.wait_until_true(lambda: router1.ha_state == 'backup')
+
+        router1.router[l3_constants.HA_INTERFACE_KEY]['status'] = (
+            l3_constants.PORT_STATUS_ACTIVE)
+        self.agent._process_updated_router(router1.router)
+        utils.wait_until_true(lambda: router1.ha_state == 'master')
+
 
 class L3HATestFailover(framework.L3AgentTestFramework):
 
diff --git a/neutron/tests/unit/plugins/ml2/test_plugin.py b/neutron/tests/unit/plugins/ml2/test_plugin.py
index d1f8b342ac1..d305bfacda2 100644
--- a/neutron/tests/unit/plugins/ml2/test_plugin.py
+++ b/neutron/tests/unit/plugins/ml2/test_plugin.py
@@ -32,6 +32,7 @@
 from neutron.callbacks import resources
 from neutron.common import constants
 from neutron.common import exceptions as exc
+from neutron.common import topics
 from neutron.common import utils
 from neutron import context
 from neutron.db import agents_db
@@ -54,6 +55,8 @@
 from neutron.plugins.ml2.drivers import type_vlan
 from neutron.plugins.ml2 import models
 from neutron.plugins.ml2 import plugin as ml2_plugin
+from neutron.plugins.ml2 import rpc
+from neutron.services.l3_router import l3_router_plugin
 from neutron.services.qos import qos_consts
 from neutron.tests import base
 from neutron.tests.unit import _test_extension_portbindings as test_bindings
@@ -76,6 +79,7 @@
 
 DEVICE_OWNER_COMPUTE = constants.DEVICE_OWNER_COMPUTE_PREFIX + 'fake'
 HOST = 'fake_host'
+TEST_ROUTER_ID = 'router_id'
 
 
 # TODO(marun) - Move to somewhere common for reuse
@@ -873,6 +877,32 @@ def commit(self, con):
         self.assertTrue(listener.except_raised)
 
 
+class TestMl2PortsV2WithL3(test_plugin.TestPortsV2, Ml2PluginV2TestCase):
+    """For testing methods that require the L3 service plugin."""
+
+    def test_update_port_status_notify_port_event_after_update(self):
+        ctx = context.get_admin_context()
+        plugin = manager.NeutronManager.get_plugin()
+        notifier = rpc.AgentNotifierApi(topics.AGENT)
+        self.plugin_rpc = rpc.RpcCallbacks(notifier, plugin.type_manager)
+        # enable subscription for events
+        l3_router_plugin.L3RouterPlugin()
+        l3plugin = manager.NeutronManager.get_service_plugins().get(
+            p_const.L3_ROUTER_NAT)
+        host_arg = {portbindings.HOST_ID: HOST}
+        with mock.patch.object(l3plugin.l3_rpc_notifier,
+                               'routers_updated_on_host') as mock_updated:
+            with self.port(device_owner=constants.DEVICE_OWNER_ROUTER_HA_INTF,
+                           device_id=TEST_ROUTER_ID,
+                           arg_list=(portbindings.HOST_ID,),
+                           **host_arg) as port:
+                self.plugin_rpc.update_device_up(
+                    ctx, agent_id="theAgentId", device=port['port']['id'],
+                    host=HOST)
+                mock_updated.assert_called_once_with(
+                    mock.ANY, [TEST_ROUTER_ID], HOST)
+
+
 class TestMl2PluginOnly(Ml2PluginV2TestCase):
     """For testing methods that don't call drivers"""
 
diff --git a/releasenotes/notes/l3ha-agent-server-dependency-1fcb775328ac4502.yaml b/releasenotes/notes/l3ha-agent-server-dependency-1fcb775328ac4502.yaml
new file mode 100644
index 00000000000..a3df9dd791a
--- /dev/null
+++ b/releasenotes/notes/l3ha-agent-server-dependency-1fcb775328ac4502.yaml
@@ -0,0 +1,6 @@
+---
+upgrade:
+  - Server notifies L3 HA agents when HA router interface
+    port status becomes active. Then L3 HA agents spawn
+    keepalived process. So, server has to be restarted
+    before the L3 agents during upgrade.