Linux bonding

Linux Network bonding – setup

Linux network Bonding is a creation of a single bonded interface by combining 2 or more Ethernet interfaces. This helps in high availability of your network interface and offers performance improvements on your data traffic flow. Bonding is also referred as nic trunking or teaming.

Bonding allows you to aggregate multiple ports into a single group, effectively combining the bandwidth into a single connection. Bonding also allows you to create multi-gigabit pipes to transport traffic through the highest traffic areas of your network. For example, you can aggregate three megabits ports into a three-megabits trunk port. That is equivalent with having one interface with three megabytes speed

Steps for bonding in Oracle Enterprise Linux and Redhat Enterprise Linux are as follows..

Step 1.

Create the file ifcfg-bond0 with the IP address, netmask and gateway. Shown below is my test bonding config file.

# cat /etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0 
IPADDR=192.168.1.12 
NETMASK=255.255.255.0 
GATEWAY=192.168.1.1 
USERCTL=no 
BOOTPROTO=none 
ONBOOT=yes

Step 2.
Modify eth0, eth1 and eth2 configuration as shown below. Comment out, or remove the ip address, netmask, gateway and hardware address from each one of these files, since settings should only come from the ifcfg-bond0 file above. Make sure you add the MASTER and SLAVE configuration in these files.

# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0 
BOOTPROTO=none 
ONBOOT=yes 
# Settings for Bond 
MASTER=bond0 
SLAVE=yes

# cat /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1 
BOOTPROTO=none  
ONBOOT=yes 
USERCTL=no 
# Settings for bonding 
MASTER=bond0 
SLAVE=yes

# cat /etc/sysconfig/network-scripts/ifcfg-eth2
DEVICE=eth2 
BOOTPROTO=none 
ONBOOT=yes 
MASTER=bond0 
SLAVE=yes

Step 3.
Set the parameters for bond0 bonding kernel module. Select the network bonding mode based on you need. The modes are

• mode=0 (Balance Round Robin)
• mode=1 (Active backup)
• mode=2 (Balance XOR)
• mode=3 (Broadcast)
• mode=4 (802.3ad)
• mode=5 (Balance TLB)
• mode=6 (Balance ALB)

Add the following lines to /etc/modprobe.conf

# bonding commands 
alias bond0 bonding 
options bond0 mode=1 miimon=100

Step 4.

Load the bond driver module from the command prompt.

# modprobe bonding

Step 5.

Restart the network, or restart the computer.

# service network restart # Or restart computer

When the machine boots up check the proc settings.

# cat /proc/net/bonding/bond0 
Ethernet Channel Bonding Driver
Bonding Mode: adaptive load balancing 
Primary Slave: None 
Currently Active Slave: eth2 
MII Status: up 
MII Polling Interval (ms): 100 
Up Delay (ms): 0 
Down Delay (ms): 0
Slave Interface: eth2 
MII Status: up 
Link Failure Count: 0 
Permanent HW addr: 00:13:72:80: 62:f0

Look at ifconfig -a and check that your bond0 interface is active. You are done!.

To verify whether the failover bonding works..

• Do an ifdown eth0 and check /proc/net/bonding/bond0 and check the “Current Active slave”.
• Do a continuous ping to the bond0 ipaddress from a different machine and do a ifdown the active interface. The ping should not break.