CENTOS & RED-HAT bond or team multiple network interfaces (NIC) into single interface

Step #1: Create a bond0 configuration file

Red Hat Linux stores network configuration in /etc/sysconfig/network-scripts/ directory. First, you need to create bond0 config file:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0

Append following lines to it:

DEVICE=bond0
IPADDR=192.168.1.20
NETWORK=192.168.1.0
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes 

Replace above IP address with your actual IP address. Save file and exit to shell prompt.

Step #2: Modify eth0 and eth1 config files:

Open both configuration using vi text editor and make sure file read as follows for eth0 interface# 

vi /etc/sysconfig/network-scripts/ifcfg-eth0 

Modify/append directive as follows:

DEVICE=eth0
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none 

Open eth1 configuration file using vi text editor:# vi /etc/sysconfig/network-scripts/ifcfg-eth1
Make sure file read as follows for eth1 interface:

DEVICE=eth1
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none 

Save file and exit to shell prompt.

Step # 3: Load bond driver/module

Make sure bonding module is loaded when the channel-bonding interface (bond0) is brought up. You need to modify kernel modules configuration file:# 

vi /etc/modprobe.conf 

Append following two lines:

alias bond0 bonding
options bond0 mode=balance-alb miimon=100 

Save file and exit to shell prompt.

Step # 4: Test configuration

First, load the bonding module:# 

modprobe bonding

Restart networking service in order to bring up bond0 interface:#

service network restart 

Verify everything is working:# 

less /proc/net/bonding/bond0