Ethernet Bonding (Linux)

Bonding ethernet channels in Linux is easy. With the right configuration and hardware, it can be done in minutes.

In this example, I have a 4 port intel Gigabit card and I wanted to utilize this and my Network switches LACP/LAG capability. Lets assume we have the Network switch part already configured to have its ports utilize LACP/LAG.

On the RHEL 4.3 server that is hosting my samba file server below are the steps outlined to configure ethernet channel bonding/teaming on the RHEL 4.3 server.

Edit the /etc/modprobe.conf file and add the bonding kernel module and its mode.

# vi /etc/modprobe.conf

#regular network card (built-in)

alias eth0 e1000

alias eth1 e1000

#the bond interface 

alias bond0 bonding

#bond interface mode. mode=4 (802.3ad/link aggregation)

options bond0 mode=4 miimon=100 

#Intel 4 port Gigabit ethernet card

alias eth5 e1000

alias eth3 e1000

alias eth4 e1000

alias eth2 e1000

alias scsi_hostadapter ahci

alias usb-controller ehci-hcd

alias usb-controller1 uhci-hcd

Now make sure to edit the /etc/sysconfig/network-scripts/ifcfg-ethX (where X are the ethernet ports that will be part of the bond0 LACP interface) 

# vi /etc/sysconfig/network-scripts/ifcfg-eth2

DEVICE=eth2

USERCTL=no

ONBOOT=yes

MASTER=bond0

SLAVE=yes

BOOTPROTO=none

TYPE=Ethernet

Now we don't want to edit every single file as its a boring and error prone process

# for i in {3..5} ; do cp /etc/sysconfig/network-scripts/ifcfg-eth2 /etc/sysconfig/network-scripts/ifcfg-eth$i ; done

#for i in {3..5} ; do sed -i "s/DEVICE=eth2/DEVICE=eth$i/g" /etc/sysconfig/network-scripts/ifcfg-eth$i ; done

Now create the bond0 interface configuration file.

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

DEVICE=bond0

IPADDR=192.168.1.30

NETWORK=192.168.1.0

NETMASK=255.255.255.0

USERCTL=no

BOOTPROTO=none

ONBOOT=yes

TYPE=Ethernet

Load the bonding kernel module.

# modprobe bonding

Now bring up the bond0 interface

# ifup bond0

Verify the bond0 interface

# cat /proc/net/bonding/bond0 

Ethernet Channel Bonding Driver: v2.6.1 (October 29, 2004)

Bonding Mode: IEEE 802.3ad Dynamic link aggregation

MII Status: up

MII Polling Interval (ms): 100

Up Delay (ms): 0

Down Delay (ms): 0

802.3ad info

LACP rate: slow

Active Aggregator Info:

        Aggregator ID: 1

        Number of ports: 1

        Actor Key: 17

        Partner Key: 1

        Partner Mac Address: 00:00:00:00:00:00

Slave Interface: eth2

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:15:17:6a:c1:e4

Aggregator ID: 1

Slave Interface: eth3

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:15:17:6a:c1:e5

Aggregator ID: 2

Slave Interface: eth4

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:15:17:6a:c1:e6

Aggregator ID: 3

Slave Interface: eth5

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:15:17:6a:c1:e7

Aggregator ID: 4

You can now try transferring files to/from the samba servers shared folders, once the transfer process is on-going, try unplugging the network cables that are part of the bond/LACP/LAG on the Network switch or on the configured 4 port Intel ethernet card.