LinuxStories: Configure NIC(Network Interface Card) bonding in CentOS 7 / RHEL 7

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NIC(Network Interface Card) bonding is also known as Network bonding. It can be defined as the aggregation or combination of multiple NIC  into a single bond interface. It’s main purpose is to provide high availability and redundancy.

In this article we will learn how to configure nic or netwok bonding in CentOS 7 & RHEL 7. In my case I have two interface cards (enp0s3 & enp0s8) and will form a bond interface (bond0).

Prerequisite

If bonding module is not loaded on your linux box then use the below command to load.

 

If bonding module is not loaded on your linux box then use the below command to load.

 

[root@openstack ~]# modprobe bonding

 

To list the bonding module info, use following command.

 

[root@openstack ~]# modinfo bonding

 

Output will be something like below

Step:1 Create Bond Interface File

Create a bond interface file (ifcfg-bond0) under the folder “/etc/sysconfig/network-scripts/”

[root@openstack network-scripts]# vi ifcfg-bond0
DEVICE=bond0
TYPE=Bond
NAME=bond0
BONDING_MASTER=yes
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.168.1.70
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
BONDING_OPTS="mode=5 miimon=100"

Save & exit the file.
Specify the IP address, Netmask & bonding modes as per your requirement. In my example i am using ‘mode=5′ which is used to provide fault tolerance and load balancing.

Step:2 Edit the NIC interface files

For ifcfg-enp0s3

[root@openstack ~]# vi /etc/sysconfig/network-scripts/ifcfg-enp0s3
TYPE=Ethernet
BOOTPROTO=none
DEVICE=enp0s3
ONBOOT=yes
HWADDR="08:00:27:69:60:c9"
MASTER=bond0
SLAVE=yes

For ifcfg-enp0s8

[root@openstack ~]# cat /etc/sysconfig/network-scripts/ifcfg-enp0s8
TYPE=Ethernet
BOOTPROTO=none
DEVICE=enp0s8
ONBOOT=yes
HWADDR="08:00:27:ea:71:8d"
MASTER=bond0
SLAVE=yes

 

Step:3 Restart the Network Service

Below command will restart the network service and will bring above changes into the effect.

[root@openstack ~]# systemctl restart network.service

 

Step:4 Test & Verify bond interface.

Use ‘ifconfig‘ & ‘ip add‘ command to check bond interface along with its slave interfaces.



Use following command to view bond interface settings like bonding mode & slave interface.

[root@openstack ~]# cat /proc/net/bonding/bond0

Step:5 Fault tolerance testing

To test the fault tolerance we can down one interface and check whether you are still able access the server.

[root@openstack ~]# ifdown enp0s8
Device 'enp0s8' successfully disconnected.
[root@openstack ~]#

Source: http://www.linuxtechi.com/configure-nic-bonding-in-centos-7-rhel-7/

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