diff --git a/neutron/agent/dhcp/agent.py b/neutron/agent/dhcp/agent.py
index b2f14df2d7a..44fa3686885 100644
--- a/neutron/agent/dhcp/agent.py
+++ b/neutron/agent/dhcp/agent.py
@@ -245,6 +245,12 @@ class DhcpAgent(manager.Manager):
                 if subnet.ip_version == 4 and subnet.enable_dhcp:
                     self.enable_isolated_metadata_proxy(network)
                     break
+        elif (self.conf.use_namespaces and not self.conf.force_metadata and
+              not self.conf.enable_isolated_metadata):
+            # In the case that the dhcp agent ran with metadata enabled,
+            # and dhcp agent now starts with metadata disabled, check and
+            # delete any metadata_proxy.
+            self.disable_isolated_metadata_proxy(network)
 
     def disable_dhcp_helper(self, network_id):
         """Disable DHCP for a network known to the agent."""
diff --git a/neutron/tests/functional/agent/test_dhcp_agent.py b/neutron/tests/functional/agent/test_dhcp_agent.py
index 40238a8c826..984b61c66cf 100644
--- a/neutron/tests/functional/agent/test_dhcp_agent.py
+++ b/neutron/tests/functional/agent/test_dhcp_agent.py
@@ -27,6 +27,7 @@ from neutron.agent.common import ovs_lib
 from neutron.agent.dhcp import agent
 from neutron.agent import dhcp_agent
 from neutron.agent.linux import dhcp
+from neutron.agent.linux import external_process
 from neutron.agent.linux import interface
 from neutron.agent.linux import ip_lib
 from neutron.agent.linux import utils
@@ -80,6 +81,8 @@ class DHCPAgentOVSTestFramework(base.BaseSudoTestCase):
 
         self.ovs_driver = interface.OVSInterfaceDriver(self.conf)
 
+        self.conf.set_override('check_child_processes_interval', 1, 'AGENT')
+
     def network_dict_for_dhcp(self, dhcp_enabled=True, ip_version=4):
         net_id = uuidutils.generate_uuid()
         subnet_dict = self.create_subnet_dict(
@@ -232,6 +235,12 @@ class DHCPAgentOVSTestFramework(base.BaseSudoTestCase):
         self.addCleanup(proc.wait)
         self.addCleanup(proc.kill)
 
+    def _get_metadata_proxy_process(self, network):
+        return external_process.ProcessManager(
+            self.conf,
+            network.id,
+            network.namespace)
+
 
 class DHCPAgentOVSTestCase(DHCPAgentOVSTestFramework):
 
@@ -260,3 +269,38 @@ class DHCPAgentOVSTestCase(DHCPAgentOVSTestFramework):
         port.mac_address = str(bad_mac_address)
         self._plug_port_for_dhcp_request(network, port)
         self.assert_bad_allocation_for_port(network, port)
+
+    def _spawn_network_metadata_proxy(self):
+        network = self.network_dict_for_dhcp()
+        self.conf.set_override('enable_isolated_metadata', True)
+        self.addCleanup(self.agent.disable_isolated_metadata_proxy, network)
+        self.configure_dhcp_for_network(network=network)
+        pm = self._get_metadata_proxy_process(network)
+        utils.wait_until_true(
+            lambda: pm.active,
+            timeout=5,
+            sleep=0.01,
+            exception=RuntimeError("Metadata proxy didn't spawn"))
+        return (pm, network)
+
+    def test_metadata_proxy_respawned(self):
+        pm, network = self._spawn_network_metadata_proxy()
+        old_pid = pm.pid
+
+        utils.execute(['kill', '-9', old_pid], run_as_root=True)
+        utils.wait_until_true(
+            lambda: pm.active and pm.pid != old_pid,
+            timeout=5,
+            sleep=0.1,
+            exception=RuntimeError("Metadata proxy didn't respawn"))
+
+    def test_stale_metadata_proxy_killed(self):
+        pm, network = self._spawn_network_metadata_proxy()
+
+        self.conf.set_override('enable_isolated_metadata', False)
+        self.configure_dhcp_for_network(network=network)
+        utils.wait_until_true(
+            lambda: not pm.active,
+            timeout=5,
+            sleep=0.1,
+            exception=RuntimeError("Stale metadata proxy didn't get killed"))
diff --git a/neutron/tests/unit/agent/dhcp/test_agent.py b/neutron/tests/unit/agent/dhcp/test_agent.py
index a1953f462d2..b55204b0627 100644
--- a/neutron/tests/unit/agent/dhcp/test_agent.py
+++ b/neutron/tests/unit/agent/dhcp/test_agent.py
@@ -617,11 +617,14 @@ class TestDhcpAgentEventHandler(base.BaseTestCase):
             mock.call.get_network_info(network.id)])
         self.call_driver.assert_called_once_with('enable', network)
         self.cache.assert_has_calls([mock.call.put(network)])
-        if is_isolated_network:
+        if is_isolated_network and enable_isolated_metadata:
             self.external_process.assert_has_calls([
                 self._process_manager_constructor_call(),
-                mock.call().enable()
-            ])
+                mock.call().enable()])
+        elif not enable_isolated_metadata:
+            self.external_process.assert_has_calls([
+                self._process_manager_constructor_call(ns=None),
+                mock.call().disable()])
         else:
             self.assertFalse(self.external_process.call_count)
 
@@ -723,6 +726,7 @@ class TestDhcpAgentEventHandler(base.BaseTestCase):
     def test_enable_dhcp_helper_driver_failure(self):
         self.plugin.get_network_info.return_value = fake_network
         self.call_driver.return_value = False
+        cfg.CONF.set_override('enable_isolated_metadata', True)
         self.dhcp.enable_dhcp_helper(fake_network.id)
         self.plugin.assert_has_calls(
             [mock.call.get_network_info(fake_network.id)])