Linux Server Bonding

Nowadays all servers come with multiple network ports that can be used for
varied purposes. You can use one port for networking, another for heartbeat
monitoring and a few others for server fail overs. In Linux you can use the
bonding kernel module for load balancing or Hot standby. The module combines
multiple NICs into a single virtual interface. Most Linux distros ship with a
Linux bonding driver. In our tests we used CentOS as it is a standard Server
Distro based on Red Hat. Let's see how to configure bonding in it.

First we will load Linux bond driver. To do this open /etc/modprobe.conf and
add:

#alias bond0 bonding

#options bond0 mode=balance-alb miimon=100

This will create a bond0 device which will use the bonding kernel module.

To create a bond0 configuration file run the following command from the
shell:

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

Add following lines to the file and in IPADDR replace the IP Address with
your server's IP Address:

DEVICE=bond0

USERCTL=no

ONBOOT=yes

BOOTPROTO=none

IPADDR=192.168.6.8

NETWORK=192.168.6.0

NETMASK=255.255.255.0

Next alter eth1 and eth0 configuration files. To do this first open
'ifcfg-eth0' in 'vi' or any other text editor and add following lines to it:

Using 'Less' command you can check the mode in which you have configured bonding along with bonding detail

DEVICE=eth0

USERCTL=no

OOTPROTO=none

ONBOOT=yes

MASTER=bond0

SLAVE=yes

\Similarly open 'ifcfg-eth1' file and add:

\DEVICE=eth1

USERCTL=no

BOOTPROTO=none

ONBOOT=yes

MASTER=bond0

SLAVE=yes

To start the bonding module run:

# modprobe bonding

And now restart the network

service. To confirm that bonding is working run:

# less /proc/net/bonding/bond0

Now you should see confirmation of bonding as shown in the visual.