Network Bonding on CentOS 6

Network Bonding is the aggregation of multiple lan cards(eth0 & eth1) into a single interface called bond interface. Network Bonding is a kernel feature and also known as NIC teaming. Bonding is generally required to provide high availability and load balancing services.

1.Create the bond file ( ifcfg-bond0 ) and specify the ip address, netmask & gateway.

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

DEVICE=bond0
IPADDR=192.168.1.9
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
TYPE=Bond
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=static

2.Edit the files of eth0 & eth1 and make sure you enter the master and slave entry, as shown below

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

DEVICE=eth0

HWADDR=08:00:27:5C:A8:8F

TYPE=Ethernet

ONBOOT=yes

NM_CONTROLLED=no

MASTER=bond0

SLAVE=yes

# vi /etc/sysconfig/network-scripts/ifcfg-eth1

DEVICE=eth1

HWADDR=08:00:27:7f:04:49

TYPE=Ethernet

ONBOOT=yes

NM_CONTROLLED=no

MASTER=bond0

SLAVE=yes

3.Create the Bond file (bonding.conf)

alias bond0 bonding

options bond0 mode=1 miimon=100  (active and passive)

4.Activate bonding driver

# modprobe bonding

# service network restart

# ifconfig bond0

 bond0     Link encap:Ethernet  HWaddr 08:00:27:5C:A8:8F
 inet addr:192.168.1.9  Bcast:192.168.1.255  Mask:255.255.255.0
 inet6 addr: fe80::a00:27ff:fe5c:a88f/64 Scope:Link
 UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1
 RX packets:6164 errors:0 dropped:0 overruns:0 frame:0
 TX packets:1455 errors:0 dropped:0 overruns:0 carrier:0
 collisions:0 txqueuelen:0
 RX bytes:482336 (471.0 KiB)  TX bytes:271221 (264.8 KiB

5.Verify the Status of bond interface.

# cat /proc/net/bonding/bond0  

 Ethernet Channel Bonding Driver: v3.6.0 (September 26, 2009)

Bonding Mode: fault-tolerance (active-backup)

 Primary Slave: None

 Currently Active Slave: eth0

 MII Status: up

 MII Polling Interval (ms): 100

 Up Delay (ms): 0

 Down Delay (ms): 0

Slave Interface: eth0

 MII Status: up

 Speed: 1000 Mbps

 Duplex: full

 Link Failure Count: 0

 Permanent HW addr: 08:00:27:5c:a8:8f

 Slave queue ID: 0

Slave Interface: eth1

 MII Status: up

 Speed: 1000 Mbps

 Duplex: full

 Link Failure Count: 0

 Permanent HW addr: 08:00:27:7f:04:49

 Slave queue ID: 0

6.Different Modes used in bonding.conf file .

balance-rr or 0 — round-robin mode for fault tolerance and load balancing.

active-backup or 1 — Sets active-backup mode for fault tolerance.

balance-xor or 2 — Sets an XOR (exclusive-or) mode for fault tolerance and load balancing.

broadcast or 3 — Sets a broadcast mode for fault tolerance. All transmissions are sent on all slave interfaces.

802.3ad or 4 — Sets an IEEE 802.3ad dynamic link aggregation mode. Creates aggregation groups that share the same speed & duplex settings.

balance-tlb or 5 — Sets a Transmit Load Balancing (TLB) mode for fault tolerance & load balancing.

balance-alb or 6 — Sets an Active Load Balancing (ALB) mode for fault tolerance & load balancing.