Bombproofing: “Bonding” Multiple NICs to One Network Interface

Concept: Two network cards backing one IP address. One card fails, you’re still up.

linux channel bonding

Example will show bonding of 2 network cards to one IP address (macs and IPs changed to protect the innocent).

Step 1: Create /etc/modprobe.conf entries

alias bond0 bonding

Step 2: Create ifcfg-bond0 file in /etc/sysconfig/network-scripts

DEVICE=bond0
BOOTPROTO=static
BROADCAST=999.999.999.255
IPADDR=999.999.999.999
NETMASK=255.255.255.0
NETWORK=999.999.999.0
ONBOOT=yes

Step 3: Modify existing ifcfg-eth0 and ifcfg-eth1 files in /etc/sysconfig/network-scripts

(ifcfg-eth0):

DEVICE=eth0
BOOTPROTO=none
HWADDR=00:xx:xx:xx:xx:xx
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=0

(ifcfg-eth1):

DEVICE=eth1
BOOTPROTO=none
HWADDR=xx:x3:xx:xx:88:xx
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=no

Step 4: Re-initialize network

/sbin/service network restart