Fix linux_net.py interface-driver loading.

bug 950381

linux_net.py previously set the value of interface_driver based on a flag
when the module was loaded.  This breaks when nova-manage is used to
invoke anything using the interface_driver, as nova-manage loads the
nova.network.linux_net module before flags are properly set.  This patch
moves the initialization of the interface_driver variable to within a
function that will only be called once flags are properly loaded.

Note: this patch also fixes the unplug() action for the OVS vif-plugging
code to actually remove the device created to act as the gateway device.
Also tweaks the plug() to use the get_dev() method, reducing duplicate
code.

Change-Id: I97a17c010d4d6a67e2340a81315da00775c67eea

1 files changed, 17 insertions, 6 deletions

diff --git a/nova/network/linux_net.py b/nova/network/linux_net.py
index c0dbe88af..8b75635fd 100755
--- a/nova/network/linux_net.py
+++ b/nova/network/linux_net.py
@@ -907,18 +907,26 @@ def _ip_bridge_cmd(action, params, device):
 # of creating ethernet interfaces and attaching them to the network.
 # In the case of a network host, these interfaces
 # act as gateway/dhcp/vpn/etc. endpoints not VM interfaces.
+interface_driver = None
+
+
+def _get_interface_driver():
+    global interface_driver
+    if not interface_driver:
+        interface_driver = utils.import_object(FLAGS.linuxnet_interface_driver)
+    return interface_driver
 
 
 def plug(network, mac_address, gateway=True):
-    return interface_driver.plug(network, mac_address, gateway)
+    return _get_interface_driver().plug(network, mac_address, gateway)
 
 
 def unplug(network):
-    return interface_driver.unplug(network)
+    return _get_interface_driver().unplug(network)
 
 
 def get_dev(network):
-    return interface_driver.get_dev(network)
+    return _get_interface_driver().get_dev(network)
 
 
 class LinuxNetInterfaceDriver(object):
@@ -1077,7 +1085,7 @@ class LinuxBridgeInterfaceDriver(LinuxNetInterfaceDriver):
 class LinuxOVSInterfaceDriver(LinuxNetInterfaceDriver):
 
     def plug(self, network, mac_address, gateway=True):
-        dev = "gw-" + str(network['uuid'][0:11])
+        dev = self.get_dev(network)
         if not _device_exists(dev):
             bridge = FLAGS.linuxnet_ovs_integration_bridge
             _execute('ovs-vsctl',
@@ -1119,7 +1127,11 @@ class LinuxOVSInterfaceDriver(LinuxNetInterfaceDriver):
         return dev
 
     def unplug(self, network):
-        return self.get_dev(network)
+        dev = self.get_dev(network)
+        bridge = FLAGS.linuxnet_ovs_integration_bridge
+        _execute('ovs-vsctl', '--', '--if-exists', 'del-port',
+                               bridge, dev, run_as_root=True)
+        return dev
 
     def get_dev(self, network):
         dev = "gw-" + str(network['uuid'][0:11])
@@ -1208,4 +1220,3 @@ class QuantumLinuxBridgeInterfaceDriver(LinuxNetInterfaceDriver):
         return bridge
 
 iptables_manager = IptablesManager()
-interface_driver = utils.import_object(FLAGS.linuxnet_interface_driver)