Bind dual NICs in CentOS-bond0

Nic binding means that multiple NICs are logically used as one Nic. It can be divided into two types: Server Load balancer binding and redundant binding.

1. Edit the Virtual Network Interface Configuration File

[Root @ test ~] # More/etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE = bond0
IPADDR = 172.16.4.100
NETMASK = 255.255.255.0
BROADCAST = 172.16.4.255
NETWORK = 172.164.100
ONBOOT = yes

2. Edit the configuration files for each network card. Make sure that you back up the files before editing.

[Root @ test ~] # More/etc/sysconfig/network-scripts/ifcfg-eth0
BOOTPROTO = none
TYPE = Ethernet
DEVICE = eth0
ONBOOT = yes
MASTER = bond0
Slave = yes
[Root @ test ~] # More/etc/sysconfig/network-scripts/ifcfg-eth1
BOOTPROTO = none
TYPE = Ethernet
DEVICE = eth1
ONBOOT = yes
MASTER = bond0
Slave = yes

3. Modify the/etc/modprobe. conf file, back up the file, and add two lines.
Alias bond0 bonding
Options bond0 miimon = 100 mode = 1
Note:
(1) miimon indicates that the interval between link monitoring is millisecond, and miimon = 100 indicates that it checks whether the network card and the switch are connected every 100 milliseconds, if not, use another link.
(2) mode = 0 indicates the Server Load balancer mode. Both NICs work and must be supported by vswitches.
Mode = 1 indicates the redundancy mode. Only one network adapter works. If one problem occurs, another one is enabled.
Mode = 6 indicates the Server Load balancer mode. Both NICs work and do not require support from vswitches.

[Root @ test ~] # More/etc/modprobe. conf
Alias eth0 b44
Alias eth1 8139too
Alias usb-controller ehci-hcd
Alias usb-controller1 ohci-hcd
Alias bond0 bonding
Options bond0 miimon = 100 mode = 0

4. Add the following line to/etc/rc. d/rc. local:
Ifenslave bond0 eth0 eth1

[Root @ test ~] # More/etc/rc. d/rc. local
#! /Bin/sh
#
# This script will be executed * after * all the other init scripts.
# You can put your own initialization stuff in here if you don't
# Want to do the full Sys V style init stuff.

Touch/var/lock/subsys/local
Ifenslave bond0 eth0 eth1

5. After the restart, the Server Load balancer is working properly. service network restart, 6. Check bond0's working status.

[Root @ test ~] # More/proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v2.6.1 (October 29,200 4)

Bonding Mode: load balancing (round-robin)
MII Status: up
MII Polling Interval (MS): 100
Up Delay (MS): 0
Down Delay (MS): 0

Slave Interface: eth0
MII Status: up
Link Failure Count: 1
Permanent HW addr: 00: 1b: b9: 58: 8b: b2

Slave Interface: eth1
MII Status: down
Link Failure Count: 0
Permanent HW addr: 00: 07: 40: 6c: ac: c8

7. view the working status of the bound Nic

[Root @ test ~] # Ifconfig-
Bond0 Link encap: Ethernet HWaddr00: 1B: B9: 58: 8B: B2

Inet addr: 172.16.4.100 Bcast: 172.16.4.255 Mask: 255.255.255.0
Inet6 addr: fe80: 200: ff: fe00: 0/64 Scope: Link
Up broadcast runningmaster multicast mtu: 1500 Metric: 1
RX packets: 744154 errors: 0 dropped: 0 overruns: 0 frame: 0
TX packets: 1866915 errors: 0 dropped: 0 overruns: 0 carrier: 0
Collisions: 0 txqueuelen: 0
RX bytes: 1099876146 (1.0GiB) TX bytes: 121233595 (115.6 MiB)

Eth0 Link encap: Ethernet HWaddr00: 1B: B9: 58: 8B: B2
Inet6 addr: fe80: 21b: b9ff: fe58: 8bb2/64 Scope: Link
Up broadcast runningslave multicast mtu: 1500 Metric: 1
RX packets: 744154 errors: 0 dropped: 0 overruns: 0 frame: 0
TX packets: 1866905 errors: 0 dropped: 0 overruns: 0 carrier: 0
Collisions: 0 FIG: 1000
RX bytes: 1099876146 (1.0GiB) TX bytes: 121232839 (115.6 MiB)
Interrupt: 9

Eth1 Link encap: Ethernet HWaddr00: 1B: B9: 58: 8B: B2
Inet6 addr: fe80: 21b: b9ff: fe58: 8bb2/64 Scope: Link
Up broadcast slavemulticast mtu: 1500 Metric: 1
RX packets: 0 errors: 0 dropped: 0 overruns: 0 frame: 0
TX packets: 10 errors: 0 dropped: 0 overruns: 0 carrier: 0
Collisions: 0 FIG: 1000
RX bytes: 0 (0.0 B) TX bytes: 756 (756.0 B)
Interrupt: 11 Baseaddress: 0x1000

Lo Link encap: Local Loopback
Inetaddr: 127.0.0.1 Mask: 255.0.0.0
Inet6 addr: 1/128 Scope: Host
Up loopbackrunning mtu: 16436 Metric: 1
RX packets: 2129 errors: 0 dropped: 0 overruns: 0 frame: 0
TX packets: 2129 errors: 0 dropped: 0 overruns: 0 carrier: 0
Collisions: 0 txqueuelen: 0
RX bytes: 1998893 (1.9MiB) TX bytes: 1998893 (1.9 MiB)

Sit0 Link encap: IPv6-in-IPv4
Noarp mtu: 1480 Metric: 1
RX packets: 0 errors: 0 dropped: 0 overruns: 0 frame: 0
TX packets: 0 errors: 0 dropped: 0 overruns: 0 carrier: 0
Collisions: 0 txqueuelen: 0
RX bytes: 0 (0.0 B) TX bytes: 0 (0.0 B)

Appendix:
DEVICE = physical DEVICE name
IPADDR = IP Address
NETMASK = mask Value
NETWORK = NETWORK address
BROADCAST = BROADCAST address
GATEWAY = GATEWAY address
ONBOOT = [yes | no] (whether to activate the device during boot)
USERCTL = [yes | no] (whether non-root users can control the device)
BOOTPROTO = [none | static | bootp | dhcp] (no protocol used during boot | static allocation | BOOTP protocol | DHCP protocol)
HWADDR = Your MAC address