Centos7 多网卡绑定实现负载均衡

1. 常见绑定模式

常用的有三种
mode=0：平衡负载模式，有自动备援，但需要交换机支持及设定，       两个交换机端口需要做聚合，该模式下bond所绑定的网卡的IP都被修改成相同的mac地址，交换机做了聚合后，聚合下的几个端口也被捆绑成一个mac地址。
mode=1：自动备援模式，其中一条线若断线，其他线路将会自动备援。
mode=6：平衡负载模式，有自动备援，不用交换机支持，绑定的是不同的MAC地址。

2. 以双网卡配置示例

#查看bonding模块是否加载
lsmod | grep bonding 
 bonding 136705 0 
#如果没有加载，手动先加载
modprobe bonding
#在/etc/sysconfig/network-scripts目录下配置ens33,ens37,bond0三个网卡接口,bond0是抽象网卡
[root@wangguan network-scripts]# cat ifcfg-enp5s0
TYPE=Ethernet
BOOTPROTO=none
DEVICE=enp5s0
ONBOOT=yes
USERCTL=no
MASTER=bond0
SLAVE=yes
BONDING_MASTER=yes

[root@wangguan network-scripts]# cat ifcfg-enp8s0
TYPE=Ethernet
BOOTPROTO=none
DEVICE=enp8s0
ONBOOT=yes
USERCTL=no
MASTER=bond0
SLAVE=yes
BONDING_MASTER=yes

#实际是把原来网卡1的ip配置放入了bond0里
[root@wangguan network-scripts]# cat ifcfg-bond0 
TYPE=Bond
DEVICE=bond0
BOOTPROTO=none
ONBOOT=yes
ZONE=public
IPADDR=192.168.2.205
NETMASK=255.255.255.0
USERCTL=no
NM_CONTROLLED=no
BONDING_MASTER=yes
BONDING_OPTS="mode=6 miimon=100"

重启网络systemctl restart network，如果原来network就没启动，那么使用systemctl start network
#enp5s0和enp8s0应该是没有配置IP的
[root@wangguan network-scripts]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
    link/ether 00:90:27:e3:02:de brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.153/24 brd 192.168.1.255 scope global enp1s0
       valid_lft forever preferred_lft forever
3: enp5s0: <NO-CARRIER,BROADCAST,MULTICAST,SLAVE,UP> mtu 1500 qdisc mq master bond0 state DOWN qlen 1000
    link/ether 00:90:27:e3:02:df brd ff:ff:ff:ff:ff:ff
4: enp7s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN qlen 1000
    link/ether 00:90:27:e3:02:e0 brd ff:ff:ff:ff:ff:ff
    inet6 2408:8207:2530:5e30:290:27ff:fee3:2e0/64 scope global mngtmpaddr dynamic 
       valid_lft 245372sec preferred_lft 158972sec
    inet6 fe80::290:27ff:fee3:2e0/64 scope link 
       valid_lft forever preferred_lft forever
5: enp8s0: <NO-CARRIER,BROADCAST,MULTICAST,SLAVE,UP> mtu 1500 qdisc mq master bond0 state DOWN qlen 1000
    link/ether 00:90:27:e3:02:e1 brd ff:ff:ff:ff:ff:ff
6: enp11s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN qlen 1000
    link/ether 00:90:27:e3:02:e2 brd ff:ff:ff:ff:ff:ff
    inet6 2408:8207:2530:5e30:290:27ff:fee3:2e2/64 scope global mngtmpaddr dynamic 
       valid_lft 245371sec preferred_lft 158971sec
    inet6 fe80::290:27ff:fee3:2e2/64 scope link 
       valid_lft forever preferred_lft forever
7: enp12s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN qlen 1000
    link/ether 00:90:27:e3:02:e3 brd ff:ff:ff:ff:ff:ff
    inet6 2408:8207:2530:5e30:290:27ff:fee3:2e3/64 scope global mngtmpaddr dynamic 
       valid_lft 245372sec preferred_lft 158972sec
    inet6 fe80::290:27ff:fee3:2e3/64 scope link 
       valid_lft forever preferred_lft forever
8: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000
    link/ether 52:54:00:9d:d6:e0 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
9: virbr0-nic: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000
    link/ether 52:54:00:9d:d6:e0 brd ff:ff:ff:ff:ff:ff
10: bond0: <NO-CARRIER,BROADCAST,MULTICAST,MASTER,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000
    link/ether 00:90:27:e3:02:df brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.205/24 brd 192.168.2.255 scope global bond0
       valid_lft forever preferred_lft forever
    inet6 fe80::290:27ff:fee3:2df/64 scope link 
       valid_lft forever preferred_lft forever