内容简介：默认情况下，在OpenStack上私有网络上开启的虚拟机接口必须配置IP，否则网络包无法到达该接口。而之前的文章<<上篇文章的示例网络拓扑如下:
默认情况下，在OpenStack上私有网络上开启的虚拟机接口必须配置IP，否则网络包无法到达该接口。而之前的文章<< OpenStack私有网络旁路部署虚拟防火墙 >>最后提到某些厂商的VFW只支持二层透明接入，那么我们怎样在OpenStack环境上跑通这样的VFW实例呢？本文来通过实例说明。
上篇文章的示例网络拓扑如下:
VFW虚拟机接口与vRouter之间依赖IP协议转发数据包。由于VFW需要二层接入，因而不能够在防火墙接口上配置IP，我们可以在VFW前添加一个伪造的vRouter(后文称为Fake vRouter)，将IP配置在该vRouter上，vRouter与VFW之间实现二层转发，网络拓扑变为:
原来拓扑对应的实际结构如图:
新拓扑对应的实际网络结构如图:
下面我们基于上篇文章的环境继续操作。我的环境为OpenStack ALL IN ONE环境，VFW虚拟机和vRouter都在同一台机器上。
我们首先给VFW虚拟机添加一个接口，原接口作入接口，新接口作为出接口。
设置OpenStack相应的环境变量后，查看 vfw 网络ID:
[root@aio ~(keystone_admin)]# neutron net-list neutron CLI is deprecated and will be removed in the future. Use openstack CLI instead. +--------------------------------------+---------+----------------------------------+-------------------------------------------------------+ | id | name | tenant_id | subnets | +--------------------------------------+---------+----------------------------------+-------------------------------------------------------+ | 16b1e02f-216f-4e38-859c-a4cb87239106 | private | 045e1b8ee842483db6819f6ff1c966f7 | 17858aee-b868-4719-bf79-f225f2120209 10.0.0.0/24 | | 6b930b9b-3a93-4300-b4d9-6312ed36432c | public | 4d885395e1b04f97a61f0288ef41e307 | 5cf81ad0-d266-4b42-9a83-2b9885f32ece 172.24.4.0/24 | | a18c3985-535e-4d18-a49e-900912de5086 | vfw | 4d885395e1b04f97a61f0288ef41e307 | fbcf8e7a-89c8-4c74-a6ef-5178f8ab0ebd 192.168.100.0/24 | | c1ed4eb2-c45b-44e8-ac26-efd592c11860 | demo | 4d885395e1b04f97a61f0288ef41e307 | 8c09028b-e730-457b-917b-5102cefcbe6f 10.10.10.0/24 | +--------------------------------------+---------+----------------------------------+-------------------------------------------------------+
在 vfw 子网中创建一个新接口:
[root@aio ~(keystone_admin)]# neutron port-create a18c3985-535e-4d18-a49e-900912de5086
neutron CLI is deprecated and will be removed in the future. Use openstack CLI instead.
Created a new port:
+-----------------------+--------------------------------------------------------------------------------------+
| Field | Value |
+-----------------------+--------------------------------------------------------------------------------------+
| admin_state_up | True |
| allowed_address_pairs | |
| binding:host_id | |
| binding:profile | {} |
| binding:vif_details | {} |
| binding:vif_type | unbound |
| binding:vnic_type | normal |
| created_at | 2018-08-08T09:40:21Z |
| description | |
| device_id | |
| device_owner | |
| extra_dhcp_opts | |
| fixed_ips | {"subnet_id": "fbcf8e7a-89c8-4c74-a6ef-5178f8ab0ebd", "ip_address": "192.168.100.8"} |
| id | f97f143d-9121-4a52-a898-850633cac943 |
| mac_address | fa:16:3e:ee:d0:27 |
| name | |
| network_id | a18c3985-535e-4d18-a49e-900912de5086 |
| port_security_enabled | True |
| project_id | 4d885395e1b04f97a61f0288ef41e307 |
| revision_number | 3 |
| security_groups | 15915a82-919a-41b4-96d3-3cac6652079d |
| status | DOWN |
| tags | |
| tenant_id | 4d885395e1b04f97a61f0288ef41e307 |
| updated_at | 2018-08-08T09:40:22Z |
+-----------------------+--------------------------------------------------------------------------------------+
将这个接口添加到虚拟机VFW上:
[root@aio ~(keystone_admin)]# nova interface-attach --port-id f97f143d-9121-4a52-a898-850633cac943 vfw [root@aio ~(keystone_admin)]# nova list +--------------------------------------+------+--------+------------+-------------+----------------------------------+ | ID | Name | Status | Task State | Power State | Networks | +--------------------------------------+------+--------+------------+-------------+----------------------------------+ | c7da7c30-fd95-4cb2-b412-45c911e320e5 | app1 | ACTIVE | - | Running | demo=10.10.10.9, 172.24.4.4 | | 2e0deaeb-d140-4d52-8289-efdc05267b52 | vfw | ACTIVE | - | Running | vfw=192.168.100.6, 192.168.100.8 | +--------------------------------------+------+--------+------------+-------------+----------------------------------+
登录到VFW虚拟机上，将虚拟机的两个网络接口串接起来模拟二层防火墙:
brctl addbr br0 brctl addif eth0 brctl addif eth1 brctl setageing br0 0 ip link set up dev eth0 ip link set up dev eth1
查看串接后的网桥:
[root@vfw ~]# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.fa163e73c1de no eth0
eth1
接着回到OpenStack宿主机来操作, 找到VFW虚拟机的接口ID:
[root@aio ~(keystone_admin)]# neutron port-list |grep 192.168.100.6
neutron CLI is deprecated and will be removed in the future. Use openstack CLI instead.
| 2cdddce0-6533-4d2d-9214-1214e0b2375b | | 4d885395e1b04f97a61f0288ef41e307 | fa:16:3e:73:c1:de | {"subnet_id": "fbcf8e7a-89c8-4c74-a6ef-5178f8ab0ebd", "ip_address": "192.168.100.6"} |
查看VFW虚拟机接口在 br-int 上的VLAN tag ID, 可以看到VLAN TAG为 4 :
[root@aio ~]# ovs-vsctl show
aef92bf7-dcdc-4b6f-9add-d30f929940ff
...
Bridge br-int
...
Port "qvo2cdddce0-65"
tag: 4
Interface "qvo2cdddce0-65"
...
ovs_version: "2.9.0"
在 br-int 上创建一个虚拟接口 vfw , 并将其VLAN TAG设置为 4 :
ovs-vsctl add-port br-int vfw -- set interface vfw type=internal ovs-vsctl set port vfw tag=4
创建连接VFW虚拟机出入接口的网桥:
ovs-vsctl add-br vfw-in ovs-vsctl add-br vfw-out
创建Fake vRouter的net namespace:
ip netns add qrouter-vfw
将 br-int 上的 vfw , vfw-in , vfw-out 三个接口都放入 qrouter-vfw 中:
ip link set dev vfw netns qrouter-vfw ip link set dev vfw-in netns qrouter-vfw ip link set dev vfw-out netns qrouter-vfw
再将VFW虚拟机的两个接口移到新建的两个网桥上:
brctl delif qbr2cdddce0-65 tap2cdddce0-65 ovs-vsctl add-port vfw-in tap2cdddce0-65 brctl delif qbrf97f143d-91 tapf97f143d-91 ovs-vsctl add-port vfw-out tapf97f143d-91
接下来，我们进入到 qrouter-vfw 中:
ip netns exec qrouter-vfw bash
此时的网络接口情况如下:
[root@aio ~(keystone_admin)]# ip a
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
26: vfw: <BROADCAST,MULTICAST> mtu 1450 qdisc noop state DOWN group default qlen 1000
link/ether a2:e9:b4:b5:63:a0 brd ff:ff:ff:ff:ff:ff
27: vfw-in: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 32:0f:41:6a:6e:43 brd ff:ff:ff:ff:ff:ff
28: vfw-out: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 3e:3c:59:c0:80:47 brd ff:ff:ff:ff:ff:ff
我们将原来VFW的IP: 192.168.100.6 配置在 br-int 上的 vfw 接口上，也就是Fake vRouter的单臂接口:
ip addr add 192.168.100.6/24 dev vfw
给 vfw-in 接口配置一个路由IP, 如: 100.100.100.100/24 :
ip addr add 100.100.100.100/24 dev vfw-in
给 vfw-out 接口配置同一个二层网络的路由IP, 如: 100.100.100.101/24 :
ip addr add 100.100.100.101/24 dev vfw-out
启动相应接口:
ip link set up dev vfw ip link set up dev vfw-in ip link set up dev vfw-out
关闭相应接口的 rp_filter 选项:
sysctl -w net.ipv4.conf.vfw.rp_filter=0 sysctl -w net.ipv4.conf.vfw-in.rp_filter=0 sysctl -w net.ipv4.conf.vfw-out.rp_filter=0 sysctl -w net.ipv4.conf.all.rp_filter=0
我们需要将 vfw 接口进入的数据包，由接口 vfw-in 转发至VFW虚拟机，数据包直接通过VFW虚拟机内部二层转发到 vfw-out 接口处，再由 vfw 接口回注到原来路径中。
首先添加一个路由表用于从 vfw 接口转发到 vfw-in 接口:
ip route add default via 100.100.100.101 dev vfw-in table 100
添加另一个路由表用于从 vfw-out 接口转发到 vfw 接口:
ip route add default via 192.168.100.1 dev vfw table 101
配置相应的路由规则:
[root@aio ~(keystone_admin)]# ip rule add iif vfw lookup 100 [root@aio ~(keystone_admin)]# ip rule add iif vfw-out lookup 101 [root@aio ~(keystone_admin)]# ip rule 0: from all lookup local 32764: from all iif vfw-out lookup 101 32765: from all iif vfw lookup 100 32766: from all lookup main 32767: from all lookup default
至此时，我们所有的配置就都完成了。
我们从外向内访问, 访问成功:
[root@aio ~]# ping 172.24.4.4 -c 2 PING 172.24.4.4 (172.24.4.4) 56(84) bytes of data. 64 bytes from 172.24.4.4: icmp_seq=1 ttl=60 time=3.07 ms 64 bytes from 172.24.4.4: icmp_seq=2 ttl=60 time=2.03 ms --- 172.24.4.4 ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1001ms rtt min/avg/max/mdev = 2.033/2.555/3.077/0.522 ms
在VFW虚拟机上抓包看结果正常:
[root@vfw ~]# tcpdump -ieth0 -nn -e icmp tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes 11:15:49.837903 32:0f:41:6a:6e:43 > 3e:3c:59:c0:80:47, ethertype IPv4 (0x0800), length 98: 172.24.4.1 > 10.10.10.9: ICMP echo request, id 19718, seq 1, length 64 11:15:49.839749 32:0f:41:6a:6e:43 > 3e:3c:59:c0:80:47, ethertype IPv4 (0x0800), length 98: 10.10.10.9 > 172.24.4.1: ICMP echo reply, id 19718, seq 1, length 64 11:15:50.838751 32:0f:41:6a:6e:43 > 3e:3c:59:c0:80:47, ethertype IPv4 (0x0800), length 98: 172.24.4.1 > 10.10.10.9: ICMP echo request, id 19718, seq 2, length 64 11:15:50.840022 32:0f:41:6a:6e:43 > 3e:3c:59:c0:80:47, ethertype IPv4 (0x0800), length 98: 10.10.10.9 > 172.24.4.1: ICMP echo reply, id 19718, seq 2, length 64 ^C 4 packets captured 4 packets received by filter 0 packets dropped by kernel
再从app虚拟机访问外部，访问也正常:
$ ping 114.114.114.114 -c 2 PING 114.114.114.114 (114.114.114.114): 56 data bytes 64 bytes from 114.114.114.114: seq=0 ttl=58 time=27.473 ms 64 bytes from 114.114.114.114: seq=1 ttl=82 time=27.177 ms --- 114.114.114.114 ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max = 27.177/27.325/27.473 ms
从VFW虚拟机上抓包结果正常:
[root@vfw ~]# tcpdump -ieth0 -nn -e icmp tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes 11:17:33.030527 32:0f:41:6a:6e:43 > 3e:3c:59:c0:80:47, ethertype IPv4 (0x0800), length 98: 10.10.10.9 > 114.114.114.114: ICMP echo request, id 39425, seq 0, length 64 11:17:33.055787 32:0f:41:6a:6e:43 > 3e:3c:59:c0:80:47, ethertype IPv4 (0x0800), length 98: 114.114.114.114 > 10.10.10.9: ICMP echo reply, id 39425, seq 0, length 64 11:17:34.031610 32:0f:41:6a:6e:43 > 3e:3c:59:c0:80:47, ethertype IPv4 (0x0800), length 98: 10.10.10.9 > 114.114.114.114: ICMP echo request, id 39425, seq 1, length 64 11:17:34.056536 32:0f:41:6a:6e:43 > 3e:3c:59:c0:80:47, ethertype IPv4 (0x0800), length 98: 114.114.114.114 > 10.10.10.9: ICMP echo reply, id 39425, seq 1, length 64 ^C 4 packets captured 4 packets received by filter 0 packets dropped by kernel
这种方法是比较Tricky的实现，只用于POC验证阶段。如果用于实际业务场景，需要修改 Neutron 代码或者独立实现AGENT完成相应操作。更为优雅的方式，则可以基于 networking-sfc 实现二层接入，后续再写文章来说明。
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