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How to configure a failover IP on CentOS

Reviewed on 22 January 2024 • Published on 29 July 2021

This page shows you how to configure a failover IP on Dedibox servers running on CentOS.

Before you start

To complete the actions presented below, you must have:

A Dedibox account logged into the console
Created a Dedibox dedicated server

Failover IP configuration using the Network Manager

Connect to your server using SSH.

Use the Network Manager tool to configure the interface by running the command:

nmtui

Note

On older CentOS/RHEL versions, you might be used to configuring the interfaces by adding a new network-scripts file in /etc/sysconfig/network-scripts/. This way of configuration has been deprecated starting from CentOS 7 and you should use the Network Manager to avoid configuration issues.

From the Network Manager interface, select Edit a connection and select the interface you want to add an alias to. Then Click Edit….
Browse through the Add … section to add another IP address.
Enter the details of your failover IP and save the settings to generate the configuration file.

Check the configuration file, to verify that the failover IP address has been added:

cat /etc/sysconfig/network-scripts/ifcfg-ens192
...
# Alias on the interface
IPADDR1="62.120.123.123"
PREFIX1="32"

Note

Replace ens192 with the name of your network interface.

Manual configuration of a failover IP

Note

On recent versions of CentOS you should always prefer the configuration using the Network Manager tool. Manual configuration is not recommended for newer versions of CentOS (versions released after CentOS 6).

Connect to your Dedibox using SSH.

Copy the default network configuration of your primary interface to create an alias:

cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scrits/ifcfg-eth0:0

Note

The file ifcfg-eth0 might be named differently, depending on your network interfaces’ name. Use ifconfig to determine the name of your network interface.

Open the file /etc/sysconfig/network-scrits/ifcfg-eth0:0 in a text editor, for example, nano, and edit it as follows:

NM_CONTROLLED="no"
DEVICE="eth0:0"
BOOTPROTO="static"
IPADDR="my_failover_ip"
NETMASK="255.255.255.255"
ONBOOT="yes"

Bring up the interface using the following command:

ifup eth0:0