What Is Netplan in Ubuntu Linux?
Netplan is the default network configuration utility in modern Ubuntu Linux distributions, designed to simplify and standardize the management of network interfaces. This article explores the purpose of Netplan, how it functions as an abstraction layer over traditional networking tools, and why it plays a critical role in standardizing network setup across desktops, servers, cloud instances, and IoT devices.
The Purpose of Netplan
Prior to Netplan's introduction in Ubuntu 17.10, Linux administrators
had to manage multiple distinct and often conflicting network management
systems. Servers typically relied on ifupdown (configured
via /etc/network/interfaces), while desktop systems managed
networking using NetworkManager. This fragmentation
required administrators to learn different configuration syntaxes and
workflows depending on whether they were deploying a headless server, a
desktop workstation, or a virtual machine.
The primary purpose of Netplan is to solve this fragmentation by providing a single, unified configuration abstraction layer. Netplan does not directly configure network interfaces at the kernel level. Instead, it reads a centralized, human-readable configuration file and translates it into instructions for the system's actual underlying network renderers (backends).
How Netplan Works
Netplan uses YAML (YAML Ain't Markup Language) files located in
/etc/netplan/ to define the state of all network
interfaces, including physical Ethernet ports, Wi-Fi connections,
bridges, VLANs, and bondings.
During boot or when manually executed, Netplan parses these YAML files and generates the necessary configuration files for one of two supported backend renderers:
- systemd-networkd: The default backend for Ubuntu
Server and cloud environments, chosen for its speed, minimal overhead,
and tight integration with
systemd. - NetworkManager: The default backend for Ubuntu Desktop, ideal for dynamic environments where users switch between Wi-Fi networks, connect to VPNs, or use graphical network applets.
By changing a single line in a Netplan YAML file
(renderer: networkd or
renderer: NetworkManager), an administrator can toggle
between these backends without rewriting interface configurations.
Key Benefits and Features
- Human-Readable Centralization: All network definitions—such as static IP assignments, DHCP settings, gateway routes, and DNS servers—are declared in structured YAML files, eliminating the need to search through disparate configuration directories.
- Safe Application with Rollback: Netplan includes
the
netplan trycommand, which temporarily applies a new configuration and requires user confirmation. If network connectivity drops or the user does not confirm within a timeout period, Netplan automatically rolls back the changes, preventing accidental lockouts on remote servers. - Cross-Platform Consistency: Because Netplan acts as a translator, the same syntax can be automated via tools like cloud-init, Ansible, or Terraform across physical servers, cloud images, and lightweight container environments.
By abstracting the complexity of lower-level network daemons into a clean, predictable framework, Netplan ensures that network administration in Ubuntu remains consistent, reliable, and straightforward.