Creating a NixOS live CD/en - Revision history

FuzzyBot: Updating to match new version of source page

2025-10-07T20:37:55Z

Updating to match new version of source page

← Older revision		Revision as of 20:37, 7 October 2025
Line 40:		Line 40:
	inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";		inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
	outputs = { self, nixpkgs }: {		outputs = { self, nixpkgs }: {
			packages.x86_64-linux.default = self.nixosConfigurations.exampleIso.config.system.build.isoImage;
	nixosConfigurations = {		nixosConfigurations = {
	exampleIso = nixpkgs.lib.nixosSystem {		exampleIso = nixpkgs.lib.nixosSystem {
Line 58:		Line 59:

	<syntaxhighlight lang="console">		<syntaxhighlight lang="console">
	~~# git init~~
	~~# git add flake.nix~~		# nix build path:$PWD
	# nix build ~~.#nixosConfigurations.exampleIso.config.system.build.isoImage~~
	</syntaxhighlight>		</syntaxhighlight>

Line 109:		Line 109:
	Static IP addresses can be set in the image itself. This can be useful for VPS installation.		Static IP addresses can be set in the image itself. This can be useful for VPS installation.

	<syntaxhighlight lang="nix">		<syntaxhighlight lang="nix" line="1">
	{		{
	...		...
	networking = {		networking = {
	usePredictableInterfaceNames = false;		usePredictableInterfaceNames = false;
	interfaces.eth0.~~ip4~~ = [{		interfaces.eth0.ipv4.addresses = [{
	address = "64.137.201.46";		address = "64.137.201.46";
	prefixLength = 24;		prefixLength = 24;

FuzzyBot: Updating to match new version of source page

2024-07-30T12:45:06Z

Updating to match new version of source page

← Older revision		Revision as of 12:45, 30 July 2024
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	== Motivation ==		== Motivation ==

	Creating a modified NixOS LiveCD out of an existing working NixOS installation has a number of benefits:		Creating a modified NixOS LiveCD out of an existing working NixOS installation has a number of benefits:

	* Ensures authenticity.		* Ensures authenticity.

	* No need for internet access.		* No need for internet access.

	* It is easy to add your own packages and configuration changes to the image.		* It is easy to add your own packages and configuration changes to the image.

	== Building ==		== Building ==

	Building minimal NixOS installation CD with the <code>nix-build</code> command by creating this <code>iso.nix</code>-file. In this example with [[Neovim]] preinstalled.		Building minimal NixOS installation CD with the <code>nix-build</code> command by creating this <code>iso.nix</code>-file. In this example with [[Neovim]] preinstalled.

	<syntaxhighlight lang="nix">		<syntaxhighlight lang="nix">
	{ config, pkgs, ... }:		{ config, pkgs, ... }:
Line 19:		Line 26:
	}		}
	</syntaxhighlight>		</syntaxhighlight>

	Build the image via:		Build the image via:

	<syntaxhighlight lang="bash">		<syntaxhighlight lang="bash">
	nix-build '<nixpkgs/nixos>' -A config.system.build.isoImage -I nixos-config=iso.nix		nix-build '<nixpkgs/nixos>' -A config.system.build.isoImage -I nixos-config=iso.nix
	</syntaxhighlight>		</syntaxhighlight>

	Alternatively, use Nix [[Flakes]] to generate a ISO installation image, using the <code>nixos-24.05</code> branch as nixpkgs source:		Alternatively, use Nix [[Flakes]] to generate a ISO installation image, using the <code>nixos-24.05</code> branch as nixpkgs source:

	{{file\|flake.nix\|nix\|<nowiki>		{{file\|flake.nix\|nix\|<nowiki>
	{		{
Line 43:		Line 54:
	}		}
	</nowiki>}}		</nowiki>}}

	The following commands will generate the iso-image:		The following commands will generate the iso-image:

	<syntaxhighlight lang="console">		<syntaxhighlight lang="console">
	# git init		# git init
Line 49:		Line 62:
	# nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage		# nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage
	</syntaxhighlight>		</syntaxhighlight>

	The resulting image can be found in <code>result</code>:		The resulting image can be found in <code>result</code>:

	<syntaxhighlight lang="console">		<syntaxhighlight lang="console">
	$ ls result/iso/		$ ls result/iso/
	nixos-24.05.20240721.63d37cc-x86_64-linux.iso		nixos-24.05.20240721.63d37cc-x86_64-linux.iso
	</syntaxhighlight>		</syntaxhighlight>

	=== Testing the image ===		=== Testing the image ===

	To inspect the contents of the ISO image:		To inspect the contents of the ISO image:

	<syntaxhighlight lang="console">		<syntaxhighlight lang="console">
	$ mkdir mnt		$ mkdir mnt
Line 63:		Line 81:
	$ umount mnt		$ umount mnt
	</syntaxhighlight>		</syntaxhighlight>

	To boot the ISO image in an emulator:		To boot the ISO image in an emulator:

	<syntaxhighlight lang="console">		<syntaxhighlight lang="console">
	$ nix-shell -p qemu		$ nix-shell -p qemu
	$ qemu-system-x86_64 -enable-kvm -m 256 -cdrom result/iso/nixos-*.iso		$ qemu-system-x86_64 -enable-kvm -m 256 -cdrom result/iso/nixos-*.iso
	</syntaxhighlight>		</syntaxhighlight>

	===SSH===		===SSH===

	In your <tt>iso.nix</tt>:		In your <tt>iso.nix</tt>:

	<syntaxhighlight lang="nix">		<syntaxhighlight lang="nix">
	{		{
Line 81:		Line 104:
	}		}
	</syntaxhighlight>		</syntaxhighlight>

	===Static IP Address===		===Static IP Address===

	Static IP addresses can be set in the image itself. This can be useful for VPS installation.		Static IP addresses can be set in the image itself. This can be useful for VPS installation.

	<syntaxhighlight lang="nix">		<syntaxhighlight lang="nix">
	{		{
Line 98:		Line 124:
	}		}
	</syntaxhighlight>		</syntaxhighlight>

	=== Building faster ===		=== Building faster ===

	The build process is slow because of compression.		The build process is slow because of compression.

	Here are some timings for <code>nix-build</code>:		Here are some timings for <code>nix-build</code>:

	{\| class="wikitable" style="margin:auto"		{\| class="wikitable" style="margin:auto"
	\|+ Compression results		\|+ Compression results
Line 115:		Line 144:
	\| <code>xz -Xdict-size 100%</code> (default) \|\| 450s \|\| 43%		\| <code>xz -Xdict-size 100%</code> (default) \|\| 450s \|\| 43%
	\|}		\|}

	See also: [https://gist.github.com/baryluk/70a99b5f26df4671378dd05afef97fce mksquashfs benchmarks]		See also: [https://gist.github.com/baryluk/70a99b5f26df4671378dd05afef97fce mksquashfs benchmarks]

	If you don't care about file size, you can use a faster compression		If you don't care about file size, you can use a faster compression
	by adding this to your <code>iso.nix</code>:		by adding this to your <code>iso.nix</code>:

	<syntaxhighlight lang="nix">		<syntaxhighlight lang="nix">
	{		{
Line 124:		Line 155:
	}		}
	</syntaxhighlight>		</syntaxhighlight>

	==See also==		==See also==

	* [https://nixos.org/manual/nixos/stable/index.html#sec-building-image NixOS Manual: Building a NixOS (Live) ISO].		* [https://nixos.org/manual/nixos/stable/index.html#sec-building-image NixOS Manual: Building a NixOS (Live) ISO].

	[[Category:NixOS]]		[[Category:NixOS]]
	[[Category:Deployment]]		[[Category:Deployment]]
	[[Category:Cookbook]]		[[Category:Cookbook]]

FuzzyBot: Updating to match new version of source page

2024-07-22T19:32:00Z

Updating to match new version of source page

← Older revision		Revision as of 19:32, 22 July 2024
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	</syntaxhighlight>		</syntaxhighlight>
	=== Testing the image ===		=== Testing the image ===

	To inspect the contents of the ISO image:		To inspect the contents of the ISO image:
	<syntaxhighlight lang="console">		<syntaxhighlight lang="console">
Line 83:		Line 82:
	</syntaxhighlight>		</syntaxhighlight>
	===Static IP Address===		===Static IP Address===

	Static IP addresses can be set in the image itself. This can be useful for VPS installation.		Static IP addresses can be set in the image itself. This can be useful for VPS installation.
	<syntaxhighlight lang="nix">		<syntaxhighlight lang="nix">

FuzzyBot: Updating to match new version of source page

2024-07-22T17:52:44Z

Updating to match new version of source page

New page

== Motivation ==
Creating a modified NixOS LiveCD out of an existing working NixOS installation has a number of benefits:
* Ensures authenticity.
* No need for internet access.
* It is easy to add your own packages and configuration changes to the image.
== Building ==
Building minimal NixOS installation CD with the <code>nix-build</code> command by creating this <code>iso.nix</code>-file. In this example with [[Neovim]] preinstalled.
<syntaxhighlight lang="nix">
{ config, pkgs, ... }:
{
imports = [
<nixpkgs/nixos/modules/installer/cd-dvd/installation-cd-minimal.nix>

# Provide an initial copy of the NixOS channel so that the user
# doesn't need to run "nix-channel --update" first.
<nixpkgs/nixos/modules/installer/cd-dvd/channel.nix>
];
environment.systemPackages = [ pkgs.neovim ];
}
</syntaxhighlight>
Build the image via:
<syntaxhighlight lang="bash">
nix-build '<nixpkgs/nixos>' -A config.system.build.isoImage -I nixos-config=iso.nix
</syntaxhighlight>
Alternatively, use Nix [[Flakes]] to generate a ISO installation image, using the <code>nixos-24.05</code> branch as nixpkgs source:
{{file|flake.nix|nix|<nowiki>
{
description = "Minimal NixOS installation media";
inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
outputs = { self, nixpkgs }: {
nixosConfigurations = {
exampleIso = nixpkgs.lib.nixosSystem {
system = "x86_64-linux";
modules = [
({ pkgs, modulesPath, ... }: {
imports = [ (modulesPath + "/installer/cd-dvd/installation-cd-minimal.nix") ];
environment.systemPackages = [ pkgs.neovim ];
})
];
};
};
};
}
</nowiki>}}
The following commands will generate the iso-image:
<syntaxhighlight lang="console">
# git init
# git add flake.nix
# nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage
</syntaxhighlight>
The resulting image can be found in <code>result</code>:
<syntaxhighlight lang="console">
$ ls result/iso/
nixos-24.05.20240721.63d37cc-x86_64-linux.iso
</syntaxhighlight>
=== Testing the image ===

To inspect the contents of the ISO image:
<syntaxhighlight lang="console">
$ mkdir mnt
$ sudo mount -o loop result/iso/nixos-*.iso mnt
$ ls mnt
boot EFI isolinux nix-store.squashfs version.txt
$ umount mnt
</syntaxhighlight>
To boot the ISO image in an emulator:
<syntaxhighlight lang="console">
$ nix-shell -p qemu
$ qemu-system-x86_64 -enable-kvm -m 256 -cdrom result/iso/nixos-*.iso
</syntaxhighlight>
===SSH===
In your <tt>iso.nix</tt>:
<syntaxhighlight lang="nix">
{
...
# Enable SSH in the boot process.
systemd.services.sshd.wantedBy = pkgs.lib.mkForce [ "multi-user.target" ];
users.users.root.openssh.authorizedKeys.keys = [
"ssh-ed25519 AaAeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee username@host"
];
...
}
</syntaxhighlight>
===Static IP Address===

Static IP addresses can be set in the image itself. This can be useful for VPS installation.
<syntaxhighlight lang="nix">
{
...
networking = {
usePredictableInterfaceNames = false;
interfaces.eth0.ip4 = [{
address = "64.137.201.46";
prefixLength = 24;
}];
defaultGateway = "64.137.201.1";
nameservers = [ "8.8.8.8" ];
};
...
}
</syntaxhighlight>
=== Building faster ===
The build process is slow because of compression.

Here are some timings for <code>nix-build</code>:
{| class="wikitable" style="margin:auto"
|+ Compression results
|-
! squashfsCompression !! Time !! Size
|-
| <code>lz4</code> || 100s || 59%
|-
| <code>gzip -Xcompression-level 1</code> || 105s || 52%
|-
| <code>gzip</code> || 210s || 49%
|-
| <code>xz -Xdict-size 100%</code> (default) || 450s || 43%
|}
See also: [https://gist.github.com/baryluk/70a99b5f26df4671378dd05afef97fce mksquashfs benchmarks]

If you don't care about file size, you can use a faster compression
by adding this to your <code>iso.nix</code>:
<syntaxhighlight lang="nix">
{
isoImage.squashfsCompression = "gzip -Xcompression-level 1";
}
</syntaxhighlight>
==See also==
* [https://nixos.org/manual/nixos/stable/index.html#sec-building-image NixOS Manual: Building a NixOS (Live) ISO].
[[Category:NixOS]]
[[Category:Deployment]]
[[Category:Cookbook]]