os-vif/vif_plug_ovs/ovs.py
Stephen Finucane 01da454fc8 vif_plug_ovs: Always set MTU when plugging devices
Recent versions of neutron have made significant changes to how MTUs
are calculated. This work appears to have been completed and it's had
knock-on effects for some installers [1] which have changed their
default MTUs accordingly. In general, it is not recommended that one
change the MTU of a network segment in-flight as it can result in
dropped packets (depending on the change). However, the combination of
a live upgrade and these recent neutron changes means this exact
thing is now happening in some deployments.

Make life a little easier for the users who see these issues by
configuring as much of the network "plumbing" as possible to use the
the latest MTU whenever we plug interfaces. This won't necessarily
resolve all packet losses immediately - the guest will have to wait for
the new MTU to be propogated with a new DHCP lease or have it set
manually by a user - but it will make the issue eventually solvable.

[1] https://bugs.launchpad.net/tripleo/+bug/1590101

Change-Id: If09eda334cddc74910dda7a4fb498b7987714be3
Closes-bug: #1649845
2017-01-09 09:48:23 +00:00

221 lines
8.4 KiB
Python

# Derived from nova/virt/libvirt/vif.py
#
# Copyright (C) 2011 Midokura KK
# Copyright (C) 2011 Nicira, Inc
# Copyright 2011 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 sys
from os_vif import objects
from os_vif import plugin
from oslo_config import cfg
from vif_plug_ovs import constants
from vif_plug_ovs import exception
from vif_plug_ovs import linux_net
class OvsPlugin(plugin.PluginBase):
"""An OVS plugin that can setup VIFs in many ways
The OVS plugin supports several different VIF types, VIFBridge
and VIFOpenVSwitch, and will choose the appropriate plugging
action depending on the type of VIF config it receives.
If given a VIFBridge, then it will create connect the VM via
a regular Linux bridge device to allow security group rules to
be applied to VM traiffic.
"""
NIC_NAME_LEN = 14
CONFIG_OPTS = (
cfg.IntOpt('network_device_mtu',
default=1500,
help='MTU setting for network interface.',
deprecated_group="DEFAULT"),
cfg.IntOpt('ovs_vsctl_timeout',
default=120,
help='Amount of time, in seconds, that ovs_vsctl should '
'wait for a response from the database. 0 is to wait '
'forever.',
deprecated_group="DEFAULT"),
)
@staticmethod
def gen_port_name(prefix, id):
return ("%s%s" % (prefix, id))[:OvsPlugin.NIC_NAME_LEN]
@staticmethod
def get_veth_pair_names(vif):
return (OvsPlugin.gen_port_name("qvb", vif.id),
OvsPlugin.gen_port_name("qvo", vif.id))
def describe(self):
return objects.host_info.HostPluginInfo(
plugin_name="ovs",
vif_info=[
objects.host_info.HostVIFInfo(
vif_object_name=objects.vif.VIFBridge.__name__,
min_version="1.0",
max_version="1.0"),
objects.host_info.HostVIFInfo(
vif_object_name=objects.vif.VIFOpenVSwitch.__name__,
min_version="1.0",
max_version="1.0"),
objects.host_info.HostVIFInfo(
vif_object_name=objects.vif.VIFVHostUser.__name__,
min_version="1.0",
max_version="1.0")
])
def _get_mtu(self, vif):
if vif.network and vif.network.mtu:
return vif.network.mtu
return self.config.network_device_mtu
def _create_vif_port(self, vif, vif_name, instance_info, **kwargs):
mtu = self._get_mtu(vif)
linux_net.create_ovs_vif_port(
vif.network.bridge,
vif_name,
vif.port_profile.interface_id,
vif.address, instance_info.uuid,
mtu,
timeout=self.config.ovs_vsctl_timeout,
**kwargs)
def _update_vif_port(self, vif, vif_name):
mtu = self._get_mtu(vif)
linux_net.update_ovs_vif_port(vif_name, mtu)
def _plug_vhostuser(self, vif, instance_info):
linux_net.ensure_ovs_bridge(vif.network.bridge,
constants.OVS_DATAPATH_NETDEV)
vif_name = OvsPlugin.gen_port_name(
constants.OVS_VHOSTUSER_PREFIX, vif.id)
args = {}
if vif.mode == "client":
args['interface_type'] = \
constants.OVS_VHOSTUSER_INTERFACE_TYPE
else:
args['interface_type'] = \
constants.OVS_VHOSTUSER_CLIENT_INTERFACE_TYPE
args['vhost_server_path'] = vif.path
self._create_vif_port(
vif, vif_name, instance_info, **args)
def _plug_bridge(self, vif, instance_info):
"""Plug using hybrid strategy
Create a per-VIF linux bridge, then link that bridge to the OVS
integration bridge via a veth device, setting up the other end
of the veth device just like a normal OVS port. Then boot the
VIF on the linux bridge using standard libvirt mechanisms.
"""
v1_name, v2_name = self.get_veth_pair_names(vif)
linux_net.ensure_bridge(vif.bridge_name)
mtu = self._get_mtu(vif)
if not linux_net.device_exists(v2_name):
linux_net.create_veth_pair(v1_name, v2_name, mtu)
linux_net.add_bridge_port(vif.bridge_name, v1_name)
linux_net.ensure_ovs_bridge(vif.network.bridge,
constants.OVS_DATAPATH_SYSTEM)
self._create_vif_port(vif, v2_name, instance_info)
else:
linux_net.update_veth_pair(v1_name, v2_name, mtu)
self._update_vif_port(vif, v2_name)
def _plug_vif_windows(self, vif, instance_info):
"""Create a per-VIF OVS port."""
if not linux_net.device_exists(vif.id):
linux_net.ensure_ovs_bridge(vif.network.bridge,
constants.OVS_DATAPATH_SYSTEM)
self._create_vif_port(vif, vif.id, instance_info)
def plug(self, vif, instance_info):
if not hasattr(vif, "port_profile"):
raise exception.MissingPortProfile()
if not isinstance(vif.port_profile,
objects.vif.VIFPortProfileOpenVSwitch):
raise exception.WrongPortProfile(
profile=vif.port_profile.__class__.__name__)
if isinstance(vif, objects.vif.VIFOpenVSwitch):
if sys.platform != constants.PLATFORM_WIN32:
linux_net.ensure_ovs_bridge(vif.network.bridge,
constants.OVS_DATAPATH_SYSTEM)
else:
self._plug_vif_windows(vif, instance_info)
elif isinstance(vif, objects.vif.VIFBridge):
if sys.platform != constants.PLATFORM_WIN32:
self._plug_bridge(vif, instance_info)
else:
self._plug_vif_windows(vif, instance_info)
elif isinstance(vif, objects.vif.VIFVHostUser):
self._plug_vhostuser(vif, instance_info)
def _unplug_vhostuser(self, vif, instance_info):
linux_net.delete_ovs_vif_port(vif.network.bridge,
OvsPlugin.gen_port_name(
constants.OVS_VHOSTUSER_PREFIX,
vif.id),
timeout=self.config.ovs_vsctl_timeout)
def _unplug_bridge(self, vif, instance_info):
"""UnPlug using hybrid strategy
Unhook port from OVS, unhook port from bridge, delete
bridge, and delete both veth devices.
"""
v1_name, v2_name = self.get_veth_pair_names(vif)
linux_net.delete_bridge(vif.bridge_name, v1_name)
linux_net.delete_ovs_vif_port(vif.network.bridge, v2_name,
timeout=self.config.ovs_vsctl_timeout)
def _unplug_vif_windows(self, vif, instance_info):
"""Remove port from OVS."""
linux_net.delete_ovs_vif_port(vif.network.bridge, vif.id,
timeout=self.config.ovs_vsctl_timeout)
def unplug(self, vif, instance_info):
if not hasattr(vif, "port_profile"):
raise exception.MissingPortProfile()
if not isinstance(vif.port_profile,
objects.vif.VIFPortProfileOpenVSwitch):
raise exception.WrongPortProfile(
profile=vif.port_profile.__class__.__name__)
if isinstance(vif, objects.vif.VIFOpenVSwitch):
if sys.platform == constants.PLATFORM_WIN32:
self._unplug_vif_windows(vif, instance_info)
elif isinstance(vif, objects.vif.VIFBridge):
if sys.platform != constants.PLATFORM_WIN32:
self._unplug_bridge(vif, instance_info)
else:
self._unplug_vif_windows(vif, instance_info)
elif isinstance(vif, objects.vif.VIFVHostUser):
self._unplug_vhostuser(vif, instance_info)