Bonding
就是讲到快网卡绑定到同一IP地址对外服务，可以实现高可用或者负载均衡。当然，直接给两块网卡设置同一IP地址是不可能的。通过bonding，虚拟一块网卡对外提供连接，物理网卡被修改为同一MAC地址。
一 Bonding 的工作模式
Mode 0 (balance-rr)
轮转（Round-robin）策略：从头到尾顺序的在每一个slave接口上面发送数据包。本模式提供负载均衡和容错的能力。
Mode 1 (active-backuop)
活动-备份（主备）策略：在绑定中，只有一个slave被激活，当且仅活动的slave接口失败是才会激活其他的slave。为了避免交换机发生混乱此时绑定的MAC地址只有一个外部端口上可见。
Mode 3 (broadcast)
广播策略：在所有的slave接口上发送所有的报文。本模式提供容错能力。
二 Bonding配置
1 创建bonding设备的配置文件
[root@CentOS68 ~]# vim /etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0
BOOTPROTO=none
BONDING_OPTS="miimon=100 mode=0"
IPADDR=200.200.200.200
PREFIX=24
GATEWAY=200.200.200.1
miimon是设置检测链路的时间，单位为毫秒。如果miimon=100，那么系统每100毫秒检测一侧链路的连接状态，如果有一条线路不通就转入另一条线路。
mode用来指定模式
2 创建slave的配置文件
既就是要加入的网卡的配置文件，这里使用eth1、eth2两块网卡，下来修改两块网卡的配置
[root@CentOS68 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1
TYPE=Ethernet
BOOTPROTO=none
MASTER=bond0
SLAVE=yes
USERCTL=0
MASTER指定测网卡属于哪个bond。SLAVE指定从属关系。USERCTL指定用户是否有控制权限。
eth2和eth1配置类似
[root@CentOS68 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth2
DEVICE=eth2
TYPE=Ethernet
BOOTPROTO=none
MASTER=bond0
SLAVE=yes
USERCTL=0
3 重启网络服务
[root@CentOS68 ~]# service NetworkManager stop #centos6上不稳定，建议关闭
[root@CentOS68 ~]# service network restart
Shutting down interface bond0: [ OK ]
Shutting down interface eth0: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface bond0: Determining if ip address 200.200.200.200 is already in use for device bond0...
[ OK ]
Bringing up interface eth0: Determining if ip address 192.168.29.68 is already in use for device eth0...
[ OK ]
可以看到已经启动成功，再来看下IP地址和MAC
[root@CentOS68 ~]# ip a
[……]
7: eth1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP qlen 1000
link/ether 00:0c:29:74:74:45 brd ff:ff:ff:ff:ff:ff
8: eth2: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master bond0 state UP qlen 1000
link/ether 00:0c:29:74:74:45 brd ff:ff:ff:ff:ff:ff
9: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
link/ether 00:0c:29:74:74:45 brd ff:ff:ff:ff:ff:ff
inet 200.200.200.200/24 brd 200.200.200.255 scope global bond0
inet6 fe80::20c:29ff:fe74:7445/64 scope link tentative dadfailed
valid_lft forever preferred_lft forever
可以看到IP地址已经生效，并且MAC地址都相同。
4 查看bond0的状态
[root@CentOS68 ~]# cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)
Bonding Mode: load balancing (round-robin)
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0
Slave Interface: eth1
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: 00:0c:29:74:74:45
Slave queue ID: 0
Slave Interface: eth2
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: 00:0c:29:74:74:4f
Slave queue ID: 0
好了，一切都很顺利
5 删除bond
[root@CentOS68 ~]# ifconfig bond0 down
[root@CentOS68 ~]# rmmod bonding
看下是否删除成功，
[root@CentOS68 ~]# ifconfig bond0
bond0: error fetching interface information: Device not found
已经找不到bond0，说明删除成功。
详细帮助：/etc/share/doc/kernel-doc-version/Documentation/networking/bonding.txt
三 nmcli实现bonding
1 添加bonding接口
[root@centos7 ~]# nmcli connection add type bond con-name mybond0 ifname bond0 mode active-backup
Connection 'mybond0' (cc101e79-3dcb-49ee-8164-89c9e877c315) successfully added.
2添加从属接口
[root@centos7 ~]# nmcli connection add type bond-slave ifname ens34 master mybond0
Connection 'bond-slave-ens34' (9c8ff11a-72ef-4d63-a950-2ab777d2a1ea) successfully added.
[root@centos7 ~]# nmcli connection add type bond-slave ifname ens38 master mybond0
Connection 'bond-slave-ens38' (c40b3e6f-32f4-4d1a-a323-aed2519cf865) successfully added.
注意：如没有指定从属接口连接名，则该名称是接口名称加类型构成
3 启动从属接口
[root@centos7 ~]# nmcli connection up bond-slave-ens34
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/40)
[root@centos7 ~]# nmcli connection up bond-slave-ens38
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/41)
4 启动bonding 绑定
[root@centos7 ~]# nmcli connection up mybond0
Connection successfully activated (master waiting for slaves) (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/48)
5 查看绑定
[root@centos7 ~]# nmcli connection show
NAME UUID TYPE DEVICE
bond-slave-ens34 9c8ff11a-72ef-4d63-a950-2ab777d2a1ea 802-3-ethernet ens34
bond-slave-ens38 c40b3e6f-32f4-4d1a-a323-aed2519cf865 802-3-ethernet ens38
mybond0 cc101e79-3dcb-49ee-8164-89c9e877c315 bond bond0
6 添加IP地址
[root@centos7 ~]# nmcli connection modify mybond0 ipv4.method manual ipv4.addresses 200.1.1.1/24
7 删除bond绑定
（1）关闭bond
[root@centos7 ~]# nmcli connection down mybond0
Connection 'mybond0' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/18)
[root@centos7 ~]#
（2）删除bond
[root@centos7 ~]# nmcli connection delete mybond0
Connection 'mybond0' (9ed2f027-bbb1-44d1-87fc-7f7275d7fe70) successfully deleted.
（3）删除从属接口
[root@centos7 ~]# nmcli connection delete bond-slave-ens34
Connection 'bond-slave-ens34' (a46ad620-d4b5-43f9-a73a-447785504a17) successfully deleted.
[root@centos7 ~]# nmcli connection delete bond-slave-ens38
Connection 'bond-slave-ens38' (66b1f44d-ad71-4576-8061-f6cba2b976e8) successfully deleted.
好了