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Table of Contents
Interface Teaming
Apr 2021
Overview
Interface teaming is the grouping of interfaces, that share a single IP Address, the OS controls which interface responds to the physical address.
There are two technologies around, Bonding and Teaming. Bonding seems to mainly be more about aggregating links, so if you have 2 x 1GB interfaces, you can in theory bond them to create a 2GB link, this does provide redundancy if one of the links goes down.
It seems that Teaming is becoming the more widely used technology for pure redundancy though, and teaming is just that, taking a couple of interfaces and making them a 'team' where either can respond (in the case that one fails).
Requirements
In this example, we are going to team two interfaces, eth0 and eth1. eth0 is already configured with a static IP Address configuration, so some editing will be required.
In short, to test teaming you will need two interfaces on your server, you can re-purpose the interface(s) being used for management, or use two free ones on another subnet.
You can either plug both interfaces in to the same vlan on a switch, or use two switches that have a link between them.
File Structure
In this example I am using CentOS, this this procedure may differ for other Linux Distros. Firstly navigate to the following directory.
/etc/sysconfig/network-scripts/
If you list the files in this directory (ls) you will see the following:
-rw-r--r--. 1 root root 259 Apr 8 21:32 ifcfg-eth0 -rw-r--r--. 1 root root 177 Apr 8 21:31 ifcfg-eth1 -rw-r--r--. 1 root root 254 Aug 24 2018 ifcfg-lo
(I have only listed the ifcfg files, not all of the files in this directory)