What Is a Netinstall Image?

Last updated: December 28, 2023

1. Overview

In the realm of operating system installation, netinstall images stand out as a unique and efficient method for setting up a system.

Unlike traditional installation mediums that contain all the necessary packages for a complete installation, netinstall images rely on the Internet to download the required software. Accordingly, this approach offers several advantages, particularly in situations where physical media is unavailable or limited.

In this tutorial, we’ll understand what a netinstall image is and the differences compared to traditional images. Finally, we’ll walk through a simple installation guide.

2. Understanding Netinstall Images

Netinstall images, also known as network install images, can be tailored for various operating systems, not just limited to Linux-based ones. Particularly, they’re compressed files that encapsulate the minimal components needed to bootstrap off the installation process.

In addition, these components typically include three parts:

Instead of including all the packages and software needed for a full installation, a netinstall image typically downloads the required packages from the Internet during the installation process.

3. Netinstall Versus Traditional Images

In this section, we’ll theoretically understand some key differences between netinstall and traditional images.

In contrast to traditional images that encompass a comprehensive set of installation files, a netinstall image serves as a streamlined initial package.

Moreover, the primary disparity lies in the installation process: while traditional images contain all necessary software, a netinstall image downloads essential packages directly from online repositories during installation.

Furthermore, let’s see three categories that are different between the two kinds of images:

  • booting mechanism
  • size
  • content

The key distinction between netinstall images and traditional installation images lies in their size, content, and mechanism of booting. Netinstall images are significantly smaller, often comprising only a few hundred megabytes, due to their limited package selection.

Additionally, this compact size makes them ideal for downloading over the Internet, even on slow connections. Finally, netinstall images request data on the network instead of fetching it locally, which is more akin to network booting instead of a local media boot.

4. Benefits of Netinstall Images

Netinstall images offer several advantages that make them a popular choice among Linux users and system administrators.

In this section, we’ll go over the main characteristics of netinstall images and their advantages.

4.1. Reduced Storage Space Footprint

Netinstall images offer a more efficient use of system resources by leaving a smaller footprint on the hard drive compared to traditional installation methods. In addition, this results in the preservation of valuable disk space, which can then be utilized for additional applications and user data.

4.2. Optimized Hardware Compatibility

Another advantage in favor of using netinstall images is that they’re tailored to minimal hardware requirements. In particular, this makes them suitable for older or low-powered systems. Consequently, this adaptability expands the range of devices that can be effectively installed.

4.3. Up-to-date Packages

Since netinstall images harness Internet connectivity, they can access the latest software repositories, ensuring that the installed packages are up-to-date with security patches and performance enhancements.

4.4. Flexible Installation

Netinstall images enable a more adaptable installation experience. Moreover, this allows us to select and download only the packages we need for specific purposes. In addition, this customization is particularly useful for servers or specialized configurations.

Finally, netinstall images are versatile and can be employed to create extremely minimal installations. This approach enables a highly streamlined installation process, effectively reducing the overall download size.

4.5. Smaller Initial Download Size

Finally, netinstall images are considerably smaller than traditional installation images. One huge advantage of that is that they minimize the amount of data that needs to be transferred over the network initially. Furthermore, this is particularly advantageous for remote installations or limited bandwidth scenarios.

5. Installing Netinstall Image

In this section, we’ll follow a step-by-step guide that walks us through the installation of netinstall image.

5.1. Download the Netinstall Image

The first step is to download the appropriate netinstall image for the desired operating system.

In particular, these images are often available from the official website or distribution repositories:

$ wget https://releases.ubuntu.com/focal/ubuntu-20.04.4-live-server-amd64.iso

Here, we used the wget command to download the image by specifying the URL we need to query. In this case, we’re downloading Ubuntu 20.04.4 LTS distribution.

5.2. Create Bootable Media

Once the netinstall image is downloaded, we transfer it onto bootable media, such as a USB flash drive or CD/DVD. In particular, this can be accomplished using various tools provided by the operating system or third-party packages.

However, we’ll opt for using the dd command line utility:

$ sudo dd if=ubuntu-20.04.4-live-server-amd64.iso of=/dev/sdb bs=4M status=progress

Next, let’s understand the above snippet:

  • sudo enables a permitted user to execute a command as the superuser
  • dd copies and converts files; in this context, it writes the ISO image to the USB drive
  • if= specifies the input file, which is the netinstall ISO image
  • 0f= specifies the output file
  • /dev/sdb is the actual identifier of our USB drive
  • bs=4M sets the block size to 4 megabytes, making the copy process more efficient

As the actual identifier of our USB drive can differ from one environment to another, it’s usually best to check the appropriate device by using the lsblk command.

5.3. Start the Installation

To start the installation, we might have to manually enter a temporary boot menu or set the appropriate boot order in the BIOS or UEFI. We insert the bootable media into the target system and restart it.

Next, our system should boot from the media, initiating the installation process. This typically involves selecting the option to install the operating system.

Finally, this step of the installation process often prompts us to choose our preferred language, region, and keyboard layout.

5.4. Configure Network Connection

If the computer we’re installing Linux on isn’t already connected to the Internet, we’ll need to configure a network connection. Specifically, this is because netinstall images require an Internet connection to download data during the installation process.

Let’s check how to configure our network connection:

$ sudo nmcli device connect eth0
[sudo] password for Dan: 
connection 'eth0' successfully activated

The command above instructs NetworkManager to activate or connect the Ethernet interface named eth0. Accordingly, when we execute this command, NetworkManager attempts to bring up the specified network interface, configures it based on DHCP or its stored settings (if any), and establishes a connection.

Furthermore, we noticed that the connection eth0 was successfully activated.

5.5. Select Required Packages

The installation process usually prompts us to select the packages we want to install. Packages are like apps for Linux.

We can manage this through a specific Text User Interface (TUI) or the apt command.

Hence, we employ apt to select the packages we need:

$ sudo apt install --yes openssh-server
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
  openssh-server
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
After this operation, 49.6 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y

In this example, we opted to install the openssh-server package. To do that, we use the apt command followed by install to instruct Linux to install a certain package.

In essence, openssh-server can ensure remote connectivity to our new system.

5.6. Post-installation Configuration

Once we’ve selected the packages we need, we can begin the installation via a specific command or through the TUI interface. It may take a while depending on the speed of our Internet connection and the size of the packages.

Once the installation is complete, the system should prompt us to set up our user account. Particularly, this is the account that we’ll use to log in to the new Linux environment.

We’re usually prompted to enter the username and password during the process of installation. However, can set up the user account from the CLI as well.

Let’s see how to create a new account using the CLI:

$ sudo useradd -m -s /bin/bash Daniel

This command creates a new user account named Daniel with a home directory and a default shell of /bin/bash.

Finally, we can reboot to the new installation and login with the user we created.

6. Conclusion

In this article, we saw how netinstall images offer a convenient and efficient method for installing Linux operating systems.

Furthermore, we looked at their ability to access up-to-date packages, tailor the installation to specific needs, and conserve disk space. We learned that while this makes them a popular choice for both beginners and experienced Linux users, on the negative side, it requires an Internet connection during the installation.

To demonstrate, we walked through downloading and using a Ubuntu netinstall ISO image.

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