Merge "Try to enable dnsmasq process several times"

neutron/agent/linux/dhcp.py

@@ -217,6 +217,14 @@ class DhcpLocalProcess(DhcpBase):
 
     def enable(self):
         """Enables DHCP for this network by spawning a local process."""
+        try:
+            common_utils.wait_until_true(self._enable)
+        except common_utils.WaitTimeout:
+            LOG.error("Failed to start DHCP process for network %s",
+                      self.network.id)
+
+    def _enable(self):
+        try:
             if self.active:
                 self.restart()
             elif self._enable_dhcp():
@@ -224,6 +232,11 @@ class DhcpLocalProcess(DhcpBase):
                 interface_name = self.device_manager.setup(self.network)
                 self.interface_name = interface_name
                 self.spawn_process()
+            return True
+        except exceptions.ProcessExecutionError as error:
+            LOG.debug("Spawning DHCP process for network %s failed; "
+                      "Error: %s", self.network.id, error)
+            return False
 
     def _get_process_manager(self, cmd_callback=None):
         return external_process.ProcessManager(
@@ -237,10 +250,9 @@ class DhcpLocalProcess(DhcpBase):
     def disable(self, retain_port=False, block=False):
         """Disable DHCP for this network by killing the local process."""
         self.process_monitor.unregister(self.network.id, DNSMASQ_SERVICE_NAME)
-        pm = self._get_process_manager()
+        self._get_process_manager().disable()
-        pm.disable()
         if block:
-            common_utils.wait_until_true(lambda: not pm.active)
+            common_utils.wait_until_true(lambda: not self.active)
         if not retain_port:
             self._destroy_namespace_and_port()
         self._remove_config_files()

neutron/tests/unit/agent/linux/test_dhcp.py

@@ -19,6 +19,7 @@ import mock
 import netaddr
 from neutron_lib.api.definitions import extra_dhcp_opt as edo_ext
 from neutron_lib import constants
+from neutron_lib import exceptions
 from oslo_config import cfg
 import oslo_messaging
 from oslo_utils import fileutils
@@ -1134,23 +1135,31 @@ class TestDhcpLocalProcess(TestBase):
     @mock.patch.object(fileutils, 'ensure_tree')
     def test_enable(self, ensure_dir):
         attrs_to_mock = dict(
-            (a, mock.DEFAULT) for a in ['active', 'interface_name']
+            (a, mock.DEFAULT) for a in
+            ['active', 'interface_name', 'spawn_process']
         )
 
         with mock.patch.multiple(LocalChild, **attrs_to_mock) as mocks:
             mocks['active'].__get__ = mock.Mock(return_value=False)
             mocks['interface_name'].__set__ = mock.Mock()
+            mocks['spawn_process'].side_effect = [
+                exceptions.ProcessExecutionError(
+                    returncode=2, message="Test dnsmasq start failed"),
+                None]
             lp = LocalChild(self.conf,
                             FakeDualNetwork())
+
             lp.enable()
 
             self.mock_mgr.assert_has_calls(
                 [mock.call(self.conf, None),
                  mock.call().setup(mock.ANY)])
-            self.assertEqual(lp.called, ['spawn'])
+            self.assertEqual(2, mocks['interface_name'].__set__.call_count)
-            self.assertTrue(mocks['interface_name'].__set__.called)
+            ensure_dir.assert_has_calls([
-            ensure_dir.assert_called_with(
+                mock.call(
-                '/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc', mode=0o755)
+                    '/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc', mode=0o755),
+                mock.call(
+                    '/dhcp/cccccccc-cccc-cccc-cccc-cccccccccccc', mode=0o755)])
 
     def _assert_disabled(self, lp):
         self.assertTrue(lp.process_monitor.unregister.called)