Today I had implemented NIC bounding (bind both NIC so that it works as a single device). We have two Custom servers that need setup with Nvidia MPC55 NIC. Idea is to keep server accessible from both NIC without using any other method.

This box act as web server. Each day it transfer over 10GB data from this box to outside world. Therefore, the network would be setup is two servers on a switch using dual network cards. I am using CentOS version 5.2.

Linux allows binding multiple network interfaces into a single channel/NIC using special kernel module called bonding. According to official bonding documentation, “The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical “bonded” interface. The behavior of the bonded interfaces depends upon the mode; generally speaking, modes provide either hot standby or load balancing services. Additionally, link integrity monitoring may be performed.”

Setting up bounding is easy with CentOS v5.2.

Step #1: Create a bond0 configuration file

CentOS 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
GATEWAY=192.168.1.1
USERCTL=yes
BOOTPROTO=none
ONBOOT=yes
PEERDNS=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=yes
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=yes
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. You can learn more about all bounding options in kernel source documentation file.

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

Output:

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

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:59

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:0c:29:c6:be:63

List all interfaces:

# ifconfig

Output:

bond0     Link encap:Ethernet  HWaddr 00:0C:29:C6:BE:59
 inet addr:192.168.1.20  Bcast:192.168.1.255  Mask:255.255.255.0
 inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
 UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1
 RX packets:2804 errors:0 dropped:0 overruns:0 frame:0
 TX packets:1879 errors:0 dropped:0 overruns:0 carrier:0
 collisions:0 txqueuelen:0
 RX bytes:250825 (244.9 KiB)  TX bytes:244683 (238.9 KiB)

eth0      Link encap:Ethernet  HWaddr 00:0C:29:C6:BE:59
 inet addr:192.168.1.20  Bcast:192.168.1.255  Mask:255.255.255.0
 inet6 addr: fe80::20c:29ff:fec6:be59/64 Scope:Link
 UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
 RX packets:2809 errors:0 dropped:0 overruns:0 frame:0
 TX packets:1390 errors:0 dropped:0 overruns:0 carrier:0
 collisions:0 txqueuelen:1000
 RX bytes:251161 (245.2 KiB)  TX bytes:180289 (176.0 KiB)
 Interrupt:11 Base address:0x1400

eth1      Link encap:Ethernet  HWaddr 00:0C:29:C6:BE:59
 inet addr:192.168.1.20  Bcast:192.168.1.255  Mask:255.255.255.0
 inet6 addr: fe80::20c:29ff:fec6:be59/64 Scope:Link
 UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
 RX packets:4 errors:0 dropped:0 overruns:0 frame:0
 TX packets:502 errors:0 dropped:0 overruns:0 carrier:0
 collisions:0 txqueuelen:1000
 RX bytes:258 (258.0 b)  TX bytes:66516 (64.9 KiB)
 Interrupt:10 Base address:0x1480

Now you have bond multiple network interfaces into a single channel (NIC).

   People who read this article have also read: