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更新时间：2022-09-13 08:25:20
学习 Neutron 系列文章：
（2）Neutron OpenvSwitch + VLAN 虚拟网络
（3）Neutron OpenvSwitch + GRE/VxLAN 虚拟网络
（4）Neutron OVS OpenFlow 流表 和 L2 Population
（9）Neutron FWaas 和 Nova Security Group
（10）Neutron VPNaas
（11）Neutron DVR
（12）Neutron VRRP
以下面的环境为例（网络节点上）：
（1）linux bridge
root@controller:/home/sammy# brctl show bridge name bridge id STP enabled interfaces brq85925305-b4 8000.563534c8d02d no tap0bb8efeb-10 tap798c87d1-a2 vxlan-25 brq96609bfa-0e 8000.0050569c4d94 no ens224 tap60dbdc2f-a0 brq971ffda2-e5 8000.a6acb08e4fd6 no tapb1eaae00-e5 tapf70543dd-0f vxlan-10
（2）OpenStack 网络和 network namespace：
root@controller:/home/sammy# neutron net-list +--------------------------------------+---------+-----------------------------------------------------+ | id | name | subnets | +--------------------------------------+---------+-----------------------------------------------------+ | 96609bfa-0e22-4bb7-8dba-6ef532ea6076 | extnet | afa7d205-3026-439f-aca7-295a9f9b2a71 10.62.227.0/24 | | 971ffda2-e567-40a0-a2c8-b31a577fd4d3 | appnet | 4c68eacb-bf3e-408a-a941-94e93eddb22b 11.0.0.0/24 | | | | 3d596991-de8f-4ae4-8913-89426a8abbd7 10.0.0.0/24 | | 85925305-b477-4cc6-9654-67d9bf1e7cd8 | appnet2 | 4575c7f1-7f08-4917-9904-ec65af38619b 20.0.0.0/24 | +--------------------------------------+---------+-----------------------------------------------------+ root@controller:/home/sammy# ip netns qdhcp-85925305-b477-4cc6-9654-67d9bf1e7cd8 (id: 2) qdhcp-971ffda2-e567-40a0-a2c8-b31a577fd4d3 (id: 1) qrouter-39a77439-8a28-49c1-bf97-ac931510631b (id: 0)
（3）示意图：
（4）说明：
如果 external network 中有多个 subnet 的话：
（1）每个 qrouter 只允许有一个 External Gateway，也就是说它只有一个 qg network interface。当 external network 添加多个 subnet 之后，只有第一个被当作 external subnet，其余的都会被当作 internal subnet。
（2）在 qrouter 的路由表之中，
root@controller:/home/sammy# ip netns exec qrouter-39a77439-8a28-49c1-bf97-ac931510631b route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default 10.62.227.1 0.0.0.0 UG 0 0 0 qg-e09fce07-cd 10.0.0.0 * 255.255.255.0 U 0 0 0 qr-b1eaae00-e5 10.62.227.0 * 255.255.255.0 U 0 0 0 qg-e09fce07-cd 10.62.228.0 * 255.255.255.0 U 0 0 0 qg-e09fce07-cd 10.62.228.0 * 255.255.255.0 U 0 0 0 qr-124ff148-b7 11.0.0.0 * 255.255.255.0 U 0 0 0 qr-16d9b0cc-38 20.0.0.0 * 255.255.255.0 U 0 0 0 qr-0bb8efeb-10
（1）linuxbridge-agent 会启动一个循环，不断扫描上面红框中的 tap 设备
def daemon_loop(self): ... while True: start = time.time() . .. device_info = self.scan_devices(previous=device_info, sync=sync) sync = False if (self._device_info_has_changes(device_info) or self.sg_agent.firewall_refresh_needed()): LOG.debug("Agent loop found changes! %s", device_info) try: sync = self.process_network_devices(device_info) except Exception: LOG.exception(_LE("Error in agent loop. Devices info: %s"), device_info) sync = True
这是它首先找到的 devices：
(Pdb) p bridge_lib.get_bridge_names()
['brq85925305-b4', 'virbr0', 'brq971ffda2-e5', 'virbr0-nic', 'tapb1eaae00-e5', 'tapf70543dd-0f', 'vxlan-25', 'vxlan-10', 'tap0bb8efeb-10', 'lo', 'tap60dbdc2f-a0', 'tap795e6e86-94', 'ens224', 'ens192', 'ens160', 'tap798c87d1-a2']
然后过滤出 tap 设备：
get_all_devices()->set(['tap0bb8efeb-10', 'tap60dbdc2f-a0', 'tap795e6e86-94', 'tap798c87d1-a2', 'tapb1eaae00-e5', 'tapf70543dd-0f'])
（2）根据 previous 中保存的历史数据，再接合服务器端和本地更新时间，计算出需要更新的tap设备列表：
{'current': set(['tapf70543dd-0f', 'tap60dbdc2f-a0', 'tapb1eaae00-e5', 'tap795e6e86-94', 'tap0bb8efeb-10', 'tap798c87d1-a2']), 'timestamps': {'tapf70543dd-0f': 1476956816.672447, 'tap60dbdc2f-a0': None, 'tapb1eaae00-e5': 1476956816.672447, 'tap795e6e86-94': None, 'tap0bb8efeb-10': 1476689797.1378036, 'tap798c87d1-a2': 1476689701.1349163}, 'removed': set([]), 'added': set(['tapf70543dd-0f', 'tap60dbdc2f-a0', 'tapb1eaae00-e5', 'tap795e6e86-94', 'tap0bb8efeb-10', 'tap798c87d1-a2']), 'updated': set([])}(3) 通过 RPC 获取 tap 设备的详细信息
(Pdb) p devices set(['tapf70543dd-0f', 'tap60dbdc2f-a0', 'tapb1eaae00-e5', 'tap795e6e86-94', 'tap798c87d1-a2', 'tap0bb8efeb-10']) devices_details_list = self.plugin_rpc.get_devices_details_list (Pdb) p devices_details_list [{u'profile': {}, u'network_qos_policy_id': None, u'qos_policy_id': None, u'allowed_address_pairs': [], u'admin_state_up': True, u'network_id': u'971ffda2-e567-40a0-a2c8-b31a577fd4d3', u'segmentation_id': 10, u'device_owner': u'network:dhcp', u'physical_network': None, u'mac_address': u'fa:16:3e:5c:bf:11', u'device': u'tapf70543dd-0f', u'port_security_enabled': False, u'port_id': u'f70543dd-0f1b-4e1d-93c7-33f4f3d7a709', u'fixed_ips': [{u'subnet_id': u'3d596991-de8f-4ae4-8913-89426a8abbd7', u'ip_address': u'10.0.0.10'}], u'network_type': u'vxlan', u'security_groups': []}, {u'profile': {}, u'network_qos_policy_id': None, u'qos_policy_id': None, u'allowed_address_pairs': [], u'admin_state_up': True, u'network_id': u'96609bfa-0e22-4bb7-8dba-6ef532ea6076', u'segmentation_id': None, u'device_owner': u'network:router_gateway', u'physical_network': u'provider', u'mac_address': u'fa:16:3e:77:78:86', u'device': u'tap60dbdc2f-a0', u'port_security_enabled': False, u'port_id': u'60dbdc2f-a01b-446d-bb5b-26ffac19a045', u'fixed_ips': [{u'subnet_id': u'afa7d205-3026-439f-aca7-295a9f9b2a71', u'ip_address': u'10.62.227.151'}], u'network_type': u'flat', u'security_groups': []}, {u'profile': {}, u'network_qos_policy_id': None, u'qos_policy_id': None, u'allowed_address_pairs': [], u'admin_state_up': True, u'network_id': u'971ffda2-e567-40a0-a2c8-b31a577fd4d3', u'segmentation_id': 10, u'device_owner': u'network:router_interface', u'physical_network': None, u'mac_address': u'fa:16:3e:81:1b:37', u'device': u'tapb1eaae00-e5', u'port_security_enabled': False, u'port_id': u'b1eaae00-e504-41f8-93a4-643687155bea', u'fixed_ips': [{u'subnet_id': u'3d596991-de8f-4ae4-8913-89426a8abbd7', u'ip_address': u'10.0.0.1'}], u'network_type': u'vxlan', u'security_groups': []}, {u'profile': {}, u'network_qos_policy_id': None, u'qos_policy_id': None, u'allowed_address_pairs': [], u'admin_state_up': True, u'network_id': u'96609bfa-0e22-4bb7-8dba-6ef532ea6076', u'segmentation_id': None, u'device_owner': u'network:dhcp', u'physical_network': u'provider', u'mac_address': u'fa:16:3e:5f:94:7d', u'device': u'tap795e6e86-94', u'port_security_enabled': False, u'port_id': u'795e6e86-94af-4b72-ae1a-5a324a017774', u'fixed_ips': [{u'subnet_id': u'afa7d205-3026-439f-aca7-295a9f9b2a71', u'ip_address': u'10.62.227.150'}], u'network_type': u'flat', u'security_groups': []}, {u'profile': {}, u'network_qos_policy_id': None, u'qos_policy_id': None, u'allowed_address_pairs': [], u'admin_state_up': True, u'network_id': u'85925305-b477-4cc6-9654-67d9bf1e7cd8', u'segmentation_id': 25, u'device_owner': u'network:dhcp', u'physical_network': None, u'mac_address': u'fa:16:3e:25:27:99', u'device': u'tap798c87d1-a2', u'port_security_enabled': False, u'port_id': u'798c87d1-a2d8-4df7-b7fc-5ab30918a0de', u'fixed_ips': [{u'subnet_id': u'4575c7f1-7f08-4917-9904-ec65af38619b', u'ip_address': u'20.0.0.100'}], u'network_type': u'vxlan', u'security_groups': []}, {u'profile': {}, u'network_qos_policy_id': None, u'qos_policy_id': None, u'allowed_address_pairs': [], u'admin_state_up': True, u'network_id': u'85925305-b477-4cc6-9654-67d9bf1e7cd8', u'segmentation_id': 25, u'device_owner': u'network:router_interface', u'physical_network': None, u'mac_address': u'fa:16:3e:9f:18:a9', u'device': u'tap0bb8efeb-10', u'port_security_enabled': False, u'port_id': u'0bb8efeb-108f-409a-82e7-c4c20f0d4f69', u'fixed_ips': [{u'subnet_id': u'4575c7f1-7f08-4917-9904-ec65af38619b', u'ip_address': u'20.0.0.1'}], u'network_type': u'vxlan', u'security_groups': []}]
(4) 对需要处理的设备，调用 self.process_network_devices(device_info) 函数进行处理
(5). 调用 plug_interface
interface_plugged = self.mgr.plug_interface(network_id, segment,device, device_details['device_owner'])
（6）. 需要的话，使用已经配置的或者新建 linux brige，并将 physical interface 设备加入其中
bridge_name = self.get_existing_bridge_name(physical_network) #获取为 physical network 配置的 linux bridge bridge_name = self.get_bridge_name(network_id) #或者根据 network id 生成 bridge name
（7）.根据不同的网络类型，分别处理 vxlan bridge，flat bridge 和 vlan bridge
def ensure_physical_in_bridge(self, network_id, network_type, physical_network, segmentation_id): if network_type == p_const.TYPE_VXLAN: if self.vxlan_mode == lconst.VXLAN_NONE: LOG.error(_LE("Unable to add vxlan interface for network %s"), network_id) return return self.ensure_vxlan_bridge(network_id, segmentation_id) # NOTE(nick-ma-z): Obtain mappings of physical bridge and interfaces physical_bridge = self.get_existing_bridge_name(physical_network) physical_interface = self.interface_mappings.get(physical_network) if not physical_bridge and not physical_interface: LOG.error(_LE("No bridge or interface mappings" " for physical network %s"), physical_network) return if network_type == p_const.TYPE_FLAT: return self.ensure_flat_bridge(network_id, physical_bridge, physical_interface) elif network_type == p_const.TYPE_VLAN: return self.ensure_vlan_bridge(network_id, physical_bridge, physical_interface, segmentation_id)
对于 flat 类型的网络，调用 ensure_physical_in_bridge
def ensure_physical_in_bridge(self, network_id,network_type,physical_network,segmentation_id) if network_type == p_const.TYPE_FLAT: return self.ensure_flat_bridge(network_id, physical_bridge,physical_interface)
如果有配置 physical bridge 的话，使用它；否则创建 bridge，并将物理网卡配置的 ip 地址和 gateway 从网卡挪到 linux bridge
def ensure_flat_bridge(self, network_id, phy_bridge_name,physical_interface): """Create a non-vlan bridge unless it already exists.""" if phy_bridge_name: return self.ensure_bridge(phy_bridge_name) #获取预先配置好的 linux bridge else: bridge_name = self.get_bridge_name(network_id) ips, gateway = self.get_interface_details(physical_interface) if self.ensure_bridge(bridge_name, physical_interface, ips,gateway): #创建 bridge return physical_interface
对于 vxlan 类型的 network，需要创建 vxlan interface
def ensure_vxlan_bridge(self, network_id, segmentation_id): """Create a vxlan and bridge unless they already exist.""" interface = self.ensure_vxlan(segmentation_id) if not interface: LOG.error(_LE("Failed creating vxlan interface for " "%(segmentation_id)s"), {segmentation_id: segmentation_id}) return bridge_name = self.get_bridge_name(network_id) self.ensure_bridge(bridge_name, interface) return interface
创建 vxlan interface：
def ensure_vxlan(self, segmentation_id): """Create a vxlan unless it already exists.""" interface = self.get_vxlan_device_name(segmentation_id) if not ip_lib.device_exists(interface): LOG.debug("Creating vxlan interface %(interface)s for " "VNI %(segmentation_id)s", {'interface': interface, 'segmentation_id': segmentation_id}) args = {'dev': self.local_int} if self.vxlan_mode == lconst.VXLAN_MCAST: args['group'] = self.get_vxlan_group(segmentation_id) if cfg.CONF.VXLAN.ttl: args['ttl'] = cfg.CONF.VXLAN.ttl if cfg.CONF.VXLAN.tos: args['tos'] = cfg.CONF.VXLAN.tos if cfg.CONF.VXLAN.l2_population: args['proxy'] = cfg.CONF.VXLAN.arp_responder try: int_vxlan = self.ip.add_vxlan(interface, segmentation_id, **args)
（8）. 将 tap 设备加入到 linux bridge 中
bridge_lib.BridgeDevice(bridge_name).addif(tap_device_name)
（9）. 如果将一个 tap 设备被删除，那么 linux-bridge-agent 会发现：
2016-10-26 10:29:58.347 30219 INFO neutron.agent.securitygroups_rpc [req-e3264065-6414-4b5a-8d2b-dfafad6fdde8 - - - - -] Remove device filter for set(['tap60dbdc2f-a0'])
2016-10-26 10:29:58.433 30219 INFO neutron.plugins.ml2.drivers.agent._common_agent [req-e3264065-6414-4b5a-8d2b-dfafad6fdde8 - - - - -] Attachment tap60dbdc2f-a0 removed
2016-10-26 10:29:58.536 30219 INFO neutron.plugins.ml2.drivers.agent._common_agent [req-e3264065-6414-4b5a-8d2b-dfafad6fdde8 - - - - -] Port tap60dbdc2f-a0 updated.
OpenStack 官方的 host networking 配置中，连接外网的 interface 可以是 unnumbered 的，从字面意思理解，就是该 interface 上不需要配置 IP 地址。
配置的时候，修改 /etc/network/interfaces：
# The provider network interface auto ens224 iface ens224 inet manual up ip link set dev $IFACE up down ip link set dev $IFACE down
配置好以后：
root@controller:/home/sammy# ifconfig ens224 ens224 Link encap:Ethernet HWaddr 00:50:56:9c:4d:94 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:27300737 errors:0 dropped:0 overruns:0 frame:0 TX packets:61547 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:31951077598 (31.9 GB) TX bytes:5966060 (5.9 MB) root@controller:/home/sammy# ifconfig brq96609bfa-0e brq96609bfa-0e Link encap:Ethernet HWaddr 00:50:56:9c:4d:94 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:32855 errors:0 dropped:0 overruns:0 frame:0 TX packets:2 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2731030 (2.7 MB) TX bytes:84 (84.0 B)
具体原理不详，但是应该是因为 qrouter 的 qg network interface 和物理网络中的路由器的网卡之间是网络二层，因此中间的设备都是属于二层的，因此不需要处于网络三层的 IP 地址。
本文转自SammyLiu博客园博客，原文链接：http://www.cnblogs.com/sammyliu/p/5999612.html，如需转载请自行联系原作者