Linux4 step Network bonding / teaming configuration in Linux

Network bonding or network teaming is binding two physical NIC (Network Interface Card) together to create once virtual NIC. This virtual NIC serves purpose of redundancy, fault tolerance and load balancing.

For application running on system its a one NIC they are talking to but on bare metal their requests are being served by two physical cards. Hence in case one physical card is failed or unplugged, another one still serves beneath virtual NIC and applications dont even know about failure. Its same as Auto Port Aggregation in HP-UX.

As of now with RHEL7, there are 7 types of NIC bond available :

Bond 0 : Load balancing (round robin)
Bond 1 : Active backup
Bond 2 : Balance XOR
Bond 3 : Broadcast
Bond 4 : 802.3ad
Bond 5 : Balance TLB
Bond 6 : Balance ALB

We will see in detail about these types in another post. More commonly used are type 0 and type 1 bonds. Lets see step by step procedure to configure network bond in Linux.

For this tutorial, we will consider two ethernet cards eth1 and eth2 to configure bond. It is assumed that both are configured/connected to same network vlan.

Step 1:

Configure both eth with master bond0 and slave as themselves. For that, open NIC configuration file located in /etc/sysconfig/network-scripts/ifcfg-eth1 & ifcfg-eth2 in vi and edit entries as highlighted below :

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DEVICE=eth1

ONBOOT=yes

TYPE=Ethernet

BOOTPROTO=none

USERCTL=no

MASTER=bond0

SLAVE=yes

NM_CONTROLLED=no

For eth2 file, DEVICE name will be eth2.

Step 2:

Create bond0 device file under /etc/sysconfig/network-scripts/ifcfg-bond0. Add below details in it.

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DEVICE=bond0

ONBOOT=yes

IPADDR=10.10.2.5

NETMASK=255.255.255.0

BONDING_OPTS="mode=1 miimon=100"

Here under bonding options we choose mode 1. If you choose to select any other mode out of 7 mentioned above, you need to specify here against mode=

Step 3:

Make sure bonding module is loaded into kernel. Add append lines in /etc/modprobe.conf file.

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alias bond0 bonding

options bond0 mode=balance-alb miimon=100

Execute module with below command.

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# modprobe bonding

Step 4:

Thats it. You are done with configuration. You need to restart networking service and you are good to go. Make sure your network manager service is not running.

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# service network restart

Shutting down interface bond0:                             [  OK  ]

Shutting down loopback interface:                          [  OK  ]

Bringing up loopback interface:                            [  OK  ]

Bringing up interface bond0:                               [  OK  ]

You can confirm your bond0 is up with mentioned IP in ip addr command output. Bonding mode can be verified with below command :

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# cat /proc/net/bonding/bond0

Bonding Mode: load balancing (round-robin)

MII Status: up

MII Polling Interval (ms): 100

Up Delay (ms): 100

Down Delay (ms): 100

Slave Interface: eth0

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:0c:29:b6:be:32

Slave Interface: eth1

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:0c:29:b6:be:56