How to configure static IP using Netplan

From Ubuntu 17.10 onwards, the way a network is configured is completely changed. In earlier versions of Ubuntu, a static file (/etc/network/interfaces) was used for configuring network interfaces. Canonical has launched a new tool called Netplan to manage network settings. Netplan is a utility that uses YAML to configure networking on a Linux system.

What will we cover?

In this tutorial, we will learn:

1. How does Netplan work?
2. Netplan commands
3. How to use Netplan for configuring: a) Single Static IP b) Multiple Static IP c) Multiple Static IP with Multiple Gateways.

Prerequisites

1. Ubuntu 20.04 system.

2. ‘Sudo’ access and knowledge of Ubuntu networking.

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id="1">How does Netplan work?

Netplan fetches the network configuration information from a .yaml file (YAML format) . This file can reside inside the following netplan directories:

1. /etc/netplan/

2. /lib/netplan/

3. /run/netplan/

At the initial boot phase, Netplan creates backend config files inside the ‘/run’ directory and transfers control of devices to one of the supported network services/daemon: NetworkManger or Systemd-networkd.

Netplan Commands

Three commands are used in conjunction with Netplan:

netplan generate: This will generate a configuration for renderers or backends using the /etc/netplan.

netplan apply: It is used to apply all the configurations for the renderers.

netplan try: Apply a configuration, then wait for the user to confirm.

Getting started with Netplan

A basic Netplan configuration can be written as::

Netplan reads the above configuration when a system boots and generates a file as ‘/run/NetworkManager/conf.d/10-globally-managed-devices.conf’. The system will be informed that all the network configuration and device management tasks will be handled by NetworkManger. There are currently two backends: NetworkManager and systemd-networkd. Only one can be supported at a time. The default renderer is ‘systemd-networkd’.

Configuring a Static IP address using Netplan

The configuration file for Netplan(.yaml) is stored in the directory ‘/etc/netplan’. In our case, there is no config file in this directory, and no IP is assigned to the interface ‘enp0s3’:

Let’s get started now to assign a static IP on this interface. Before we dive into this tutorial, you must read the below important note:

IMPORTANT NOTE: You should first check if the below configurations works by running the command:

In this way, we can roll back our changes in the config file after a specific timeout. The following screen will appear to confirm if you want to keep changes or revert back to the configuration.

1. Setting a Single Static IP

For setting a single static IP for a system using Netplan, create a new configuration file as ‘/etc/netplan/config.yaml’. Let us modify the interface enp0s3 with the following details:

Now create or open the configuration file in the directory ‘/etc/netplan/’ with the command:

Now put the following contents in this .yaml file:

To apply the above configuration, use the command:

Now check the IP with the ‘ip’ command:

2. Setting Multiple Static IP addresses

In case we need to set multiple static IP on the above interface ‘enp0s3’, just add another address to the addresses key as shown below:

To apply the above configuration, use the command:

3. Setting Multiple Static IP addresses with Multiple Gateways

To apply the above configuration, use the command:

In all the above configurations, we have used NetworkManager as renderer; you can switch to networkd by changing the renderer from NetworkManager to networkd. A sample version of config.yaml, in this case, will be as:

Note: Since we have to configure Netplan using YAML, indentation (number of spaces) should be used properly. Otherwise, YAML will cause indentation errors like the one below:

Wrapping Up

In this guide, we have learned to set static IP using Netplan. Netplan config file is very space-sensitive as it uses the YAML format. Managing networking with Netplan is quite straightforward. You will not find it tough to master once you get used to it.