Michael_Tong
近期目标：按时吃药，努力做个正常人。
记一次bond引起的网络故障

本案中3个关键服务器
物理服务器：192.168.6.63，简称P，(Physical server)
KVM-VM：192.168.6.150，是物理服务器P上的一个KVM虚机，简称VM
NAS：外部NAS服务器，用来做ping/arp测试服务器，简称NAS

物理服务器P的配置：

#uname -a
Linux cz63 4.15.18-11-pve #1 SMP PVE 4.15.18-34 (Mon, 25 Feb 2019 14:51:06 +0100) x86_64 GNU/Linux

#cat /etc/network/interfaces
auto lo
iface lo inet loopback

auto enp3s0f0
iface enp3s0f0 inet manual

auto enp3s0f1
iface enp3s0f1 inet manual

auto ens1f0
iface ens1f0 inet manual

auto ens1f1
iface ens1f1 inet manual

auto bond0
iface bond0 inet manual
	bond-slaves enp3s0f0 enp3s0f1
	bond-miimon 100
	bond-mode balance-rr

auto bond1
iface bond1 inet manual
	bond-slaves ens1f0 ens1f1
	bond-miimon 100
	bond-mode balance-rr

auto vmbr0
iface vmbr0 inet static
	address  192.168.6.63
	netmask  255.255.255.0
	gateway  192.168.6.1
	bridge-ports bond0
	bridge-stp off
	bridge-fd 0

auto vmbr1
iface vmbr1 inet static
	address  10.1.1.63
	netmask  255.255.255.0
	bridge-ports bond1
	bridge-stp off
	bridge-fd 0
#brctl show
bridge name	bridge id		STP enabled	interfaces
vmbr0		8000.ac1f6b342094	no		bond0
							tap401000001i0
vmbr1		8000.74a4b500e768	no		bond1

安装KVM-VM，之后VM与外部服务器的连接非常不稳定，90%情况下会出现ping不可达。这里测试了centos、ubuntu、win7都是一样的不稳定。
在VM内执行ping 192.168.6.40（NAS）
结果ping不通。
此时，在P上执行
tcpdump -leni vmbr0 arp
tcpdump -leni tap401000001i0 arp
发现情况如下：

P上
#tcpdump -leni vmbr0 arp | grep 2a:f0:5f:ae:c9:8b
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
00:50:56:87:86:b9 > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.40 is-at 00:50:56:87:86:b9, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
00:50:56:87:86:b9 > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.40 is-at 00:50:56:87:86:b9, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
00:50:56:87:86:b9 > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.40 is-at 00:50:56:87:86:b9, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
00:50:56:87:86:b9 > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.40 is-at 00:50:56:87:86:b9, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
00:50:56:87:86:b9 > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.40 is-at 00:50:56:87:86:b9, length 46

P上
#tcpdump -leni tap401000001i0  arp | grep 2a:f0:5f:ae:c9:8b
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 46
2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Request who-has 192.168.6.40 (ff:ff:ff:ff:ff:ff) tell 192.168.6.150, length 28

NAS上
# tcpdump -leni vmx0 arp | grep c9:8b
02:03:50.930907 2a:f0:5f:ae:c9:8b > 00:50:56:87:86:b9, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.40 tell 192.168.6.150, length 46
02:03:50.930923 00:50:56:87:86:b9 > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 42: Reply 192.168.6.40 is-at 00:50:56:87:86:b9, length 28
02:04:02.669823 2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.32 tell 192.168.6.150, length 46
02:04:02.670131 00:50:56:87:e3:6d > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.32 is-at 00:50:56:87:e3:6d, length 46
02:04:03.670770 2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.32 tell 192.168.6.150, length 46
02:04:03.671059 00:50:56:87:e3:6d > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.32 is-at 00:50:56:87:e3:6d, length 46
02:04:04.672736 2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.32 tell 192.168.6.150, length 46
02:04:04.672992 00:50:56:87:e3:6d > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.32 is-at 00:50:56:87:e3:6d, length 46
02:04:06.671878 2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.32 tell 192.168.6.150, length 46
02:04:06.672021 00:50:56:87:e3:6d > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.32 is-at 00:50:56:87:e3:6d, length 46
02:04:07.674726 2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.32 tell 192.168.6.150, length 46
02:04:07.674773 00:50:56:87:e3:6d > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.32 is-at 00:50:56:87:e3:6d, length 46
02:04:08.676733 2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.32 tell 192.168.6.150, length 46
02:04:08.676868 00:50:56:87:e3:6d > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.32 is-at 00:50:56:87:e3:6d, length 46
02:04:10.673678 2a:f0:5f:ae:c9:8b > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: Request who-has 192.168.6.32 tell 192.168.6.150, length 46
02:04:10.674026 00:50:56:87:e3:6d > 2a:f0:5f:ae:c9:8b, ethertype ARP (0x0806), length 60: Reply 192.168.6.32 is-at 00:50:56:87:e3:6d, length 46

vmbr0上发现了2个request包和1个reply包
tap401000001i0上仅发现了request包，而且length不一致，未发现reply包。
NAS上一切正常
看到的现象就是VM在发送icmp之前需要先获得NAS的MAC地址，所以需要先通过ARP广播获取到NAS的MAC地址。

  • P的vmbr0异常：接收到2个request，1个reply
  • P的vmbr0异常：接收到reply未发送至tap401000001i0
    由于以上2个原因，导致VM无法收到reply，所以icmp不能进行，ping失败。

问题定位在数据链路层的ARP协议上。
在VM上执行arping -c 10 192.168.6.40
现象依据。再次证明以上2个现象。

# brctl show
bridge name	bridge id		STP enabled	interfaces
vmbr0		8000.ac1f6b342094	no		bond0
							tap401000001i0
vmbr1		8000.74a4b500e768	no		bond1
# brctl showstp  vmbr0
vmbr0
 bridge id		8000.ac1f6b342094
 designated root	8000.ac1f6b342094
 root port		   0			path cost		   0
 max age		  20.00			bridge max age		  20.00
 hello time		   2.00			bridge hello time	   2.00
 forward delay		   0.00			bridge forward delay	   0.00
 ageing time		 300.00
 hello timer		   0.00			tcn timer		   0.00
 topology change timer	   0.00			gc timer		   4.18
 flags


bond0 (1)
 port id		8001			state		     forwarding
 designated root	8000.ac1f6b342094	path cost		   4
 designated bridge	8000.ac1f6b342094	message age timer	   0.00
 designated port	8001			forward delay timer	   0.00
 designated cost	   0			hold timer		   0.00
 flags

tap401000001i0 (2)
 port id		8002			state		     forwarding
 designated root	8000.ac1f6b342094	path cost		 100
 designated bridge	8000.ac1f6b342094	message age timer	   0.00
 designated port	8002			forward delay timer	   0.00
 designated cost	   0			hold timer		   0.00
 flags

# brctl showmacs vmbr0
port no	mac addr		is local?	ageing timer
  1	2a:f0:5f:ae:c9:8b	no		   1.13
  1	00:50:56:87:e3:6d	no		   0.00
# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination
# ebtables -L
Bridge table: filter

Bridge chain: INPUT, entries: 0, policy: ACCEPT

Bridge chain: FORWARD, entries: 0, policy: ACCEPT

Bridge chain: OUTPUT, entries: 0, policy: ACCEPT
# ip rule show
0:	from all lookup local
32766:	from all lookup main
32767:	from all lookup default
# ip route show table all
default via 192.168.6.1 dev vmbr0 onlink
10.1.1.0/24 dev vmbr1 proto kernel scope link src 10.1.1.63
192.168.6.0/24 dev vmbr0 proto kernel scope link src 192.168.6.63
broadcast 10.1.1.0 dev vmbr1 table local proto kernel scope link src 10.1.1.63
local 10.1.1.63 dev vmbr1 table local proto kernel scope host src 10.1.1.63
broadcast 10.1.1.255 dev vmbr1 table local proto kernel scope link src 10.1.1.63
broadcast 127.0.0.0 dev lo table local proto kernel scope link src 127.0.0.1
local 127.0.0.0/8 dev lo table local proto kernel scope host src 127.0.0.1
local 127.0.0.1 dev lo table local proto kernel scope host src 127.0.0.1
broadcast 127.255.255.255 dev lo table local proto kernel scope link src 127.0.0.1
broadcast 192.168.6.0 dev vmbr0 table local proto kernel scope link src 192.168.6.63
local 192.168.6.63 dev vmbr0 table local proto kernel scope host src 192.168.6.63
broadcast 192.168.6.255 dev vmbr0 table local proto kernel scope link src 192.168.6.63
# bridge vlan show
port	vlan ids
bond0	 1 PVID Egress Untagged

vmbr0	 1 PVID Egress Untagged

bond1	 1 PVID Egress Untagged

vmbr1	 1 PVID Egress Untagged

tap401000001i0	 1 PVID Egress Untagged

以上一切正常，未发现输出问题，思路该怎么展开？

google了一下午加一个晚上，各种不解决。
最后看到了linux关于bond的说明：
https://forum.huawei.com/enterprise/zh/thread-282727.html
再看看P的网卡，明明是mode0啊！
这时候再去交换机上一看！哈啊~！

interface GigabitEthernet0/0/5
 port link-type access
 port default vlan 6
#
interface GigabitEthernet0/0/6
 port link-type access
 port default vlan 6
#
interface GigabitEthernet0/0/7
 port link-type access
 port default vlan 6
#
interface GigabitEthernet0/0/8
 port link-type access
 port default vlan 6

感觉好像是这个问题。
然后ifdown ens1f1，问题解决。
VM与所有外部网络通讯正常，无任何故障现象。
通过阅读华为网站的文章，确定了balance-rr需要交换机做修改。
不想劳烦网管，所以自己改成mode6。
一切归于平静。

问题只是临时解决了，但是产生现象的原理还没明白。
2009年自己就详细看了windows teaming linux bond的原理及配置，苦于只是知道OS层面，不知道switch侧应该怎么对应，所以知识点一直有欠缺，2017年、2018年都曾经入坑，可惜哪里有2台物理服务器和物理交换机实践一下呀！ 这次总算补齐了OS和switch的配置。
能用mode6就用mode6，再其次就是mode4。

以下给自己看的:

brctl show							#查看bridge信息
brctl showstp  vmbr0				#查看vnbr0的stp信息，是否转发等
brctl showmacs vmbr0 | grep c9:8b	#查看bridge的MAC地址
tcpdump -leni vmbr0 arp				#debug vmbr0网卡的arp包信息
tcpdump -leni vmbr0 icmp			#debug vmbr0网卡的icmp包信息
iptables -A FORWARD -i vmbr0 -o vmbr0 -j ACCEPT
iptables -L		#查看iptables
ebtables -L		#查看数据链路层的table信息
arping -c 10 192.168.1.1			#arp ping
ip rule show
ip route show table local
ip route show table all
bridge monitor			#monitor fdb update
bridge vlan show		#查看bridge的vlan信息

ping -c 1 -I veth1 192.168.3.1		#指定网卡进行ping测试

/proc/sys/net/bridge/bridge-nf-call-iptables	#干嘛的
/proc/sys/net/ipv4/ip_forward					#多网卡下，数据包转发

sysctl -a | grep bridge
net.bridge.bridge-nf-call-arptables中的0或者1代表什么意思？？

echo 1 > /proc/sys/net/ipv4/conf/eth0/arp_ignore		#什么意思？？
echo 8 > /proc/sys/net/ipv4/conf/eth0/arp_announce		#什么意思？？
posted on 2019-04-28 21:06  Michael_Tong唐唐  阅读(2474)  评论(1)  编辑  收藏  举报

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