nova创建虚机网卡实际设备的代码调用流程为
_create_domain_and_network---->plug_vifs-->LibvirtGenericVIFDriver.plug-----> plug_ovs_hybrid--->_plug_bridge_with_port。
virtualinterface使用的dirver，由vif_driver参数决定，默认值为vif_driver=nova.virt.libvirt.vif.LibvirtGenericVIFDriver
D:code-program官网nova-ocata
ovavirtlibvirtvif.py
def plug_ovs_hybrid(self, instance, vif):
"""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.
创建一个per-VIF linux网桥，然后通过一个veth设备将该网桥链接到OVS集成网桥，
将veth设备的另一端设置为正常的OVS端口。
然后使用标准libvirt机制在linux桥上引导VIF
"""
self._plug_bridge_with_port(instance, vif, port='ovs')
def _plug_bridge_with_port(self, instance, vif, port):
iface_id = self.get_ovs_interfaceid(vif)
# 获取br_name, 以qbr开头
br_name = self.get_br_name(vif['id'])
# 获取veth_pair_name, 以qvb,qvo开头
v1_name, v2_name = self.get_veth_pair_names(vif['id'])
#v1_name是qvb,v2_name是qvo
# 添加一个 qbr 网桥
if not linux_net.device_exists(br_name):
utils.execute('brctl', 'addbr', br_name, run_as_root=True)
utils.execute('brctl', 'setfd', br_name, 0, run_as_root=True)
utils.execute('brctl', 'stp', br_name, 'off', run_as_root=True)
utils.execute('tee',
('/sys/class/net/%s/bridge/multicast_snooping' %
br_name),
process_input='0',
run_as_root=True,
check_exit_code=[0, 1])
disv6 = '/proc/sys/net/ipv6/conf/%s/disable_ipv6' % br_name
if os.path.exists(disv6):
utils.execute('tee',
disv6,
process_input='1',
run_as_root=True,
check_exit_code=[0, 1])
# 创建添加一个 qvo设备
if not linux_net.device_exists(v2_name):
mtu = vif['network'].get_meta('mtu')
#v1_name是qvb,v2_name是qvo
# 将两个veth创建为一个peer-port
linux_net._create_veth_pair(v1_name, v2_name, mtu)-----s1创建peer-port设备
utils.execute('ip', 'link', 'set', br_name, 'up', run_as_root=True)
# 将qvb接口添加到qbr上
utils.execute('brctl', 'addif', br_name, v1_name, run_as_root=True)
if port == 'ovs':
# 将接口qvo桥接到br-int上
# 分别传入的参数为:br-int, qvo, port['id'], port的mac地址, instance-uuid
linux_net.create_ovs_vif_port(self.get_bridge_name(vif),------s2 将qvo桥接到br-int上
v2_name, iface_id,
vif['address'], instance.uuid,
mtu)
elif port == 'ivs':
linux_net.create_ivs_vif_port(v2_name, iface_id,
vif['address'], instance.uuid)
s1创建peer-port设备
def _create_veth_pair(dev1_name, dev2_name, mtu=None):
"""Create a pair of veth devices with the specified names,
deleting any previous devices with those names.
"""
for dev in [dev1_name, dev2_name]:
delete_net_dev(dev)
utils.execute('ip', 'link', 'add', dev1_name, 'type', 'veth', 'peer',
'name', dev2_name, run_as_root=True)
for dev in [dev1_name, dev2_name]:
utils.execute('ip', 'link', 'set', dev, 'up', run_as_root=True)
utils.execute('ip', 'link', 'set', dev, 'promisc', 'on',
run_as_root=True)
_set_device_mtu(dev, mtu)
s2 将qvo桥接到br-int上
def _create_ovs_vif_cmd(bridge, dev, iface_id, mac,
instance_id, interface_type=None):
# 将接口qvo桥接到br-int上
# 分别传入的参数为:br-int, qvo, port['id'], port的mac地址, instance-uuid
cmd = ['--', '--if-exists', 'del-port', dev, '--',
'add-port', bridge, dev,
'--', 'set', 'Interface', dev,
'external-ids:iface-id=%s' % iface_id,
'external-ids:iface-status=active',
'external-ids:attached-mac=%s' % mac,
'external-ids:vm-uuid=%s' % instance_id]
if interface_type:
cmd += ['type=%s' % interface_type]
return cmd
def create_ovs_vif_port(bridge, dev, iface_id, mac, instance_id,
mtu=None, interface_type=None):
_ovs_vsctl(_create_ovs_vif_cmd(bridge, dev, iface_id,
mac, instance_id,
interface_type))
# Note at present there is no support for setting the
# mtu for vhost-user type ports.
if interface_type != network_model.OVS_VHOSTUSER_INTERFACE_TYPE:
_set_device_mtu(dev, mtu)
else:
LOG.debug("MTU not set on %(interface_name)s interface "
"of type %(interface_type)s.",
{'interface_name': dev,
'interface_type': interface_type})
由代码可以看出,至此,<qbr>--(qvb)--(qvo)--<br-int>就已经连接上了，至于虚机是如何与<qbr>连上的,这个就是在virt内部做的了,执行以下的命令, 其中的source字段是你提供的qbr, tap则是virt生成的.
[root@test ~]# virsh domiflist 33 Interface Type Source Model MAC ------------------------------------------------------- tap437153df-04 bridge qbr437153df-04 virtio fa:16:3e:e6:99:cd
从代码中可以了解到，Nova创建虚拟机时，网络设备的创建，本质上，执行,brctl,ovs-vsctl及ip link的命令行