Adding VMs to PATH - Revision history

imported>Olafklingt: add Virtualization Category

2022-07-15T17:23:27Z

add Virtualization Category

← Older revision		Revision as of 17:23, 15 July 2022
Line 78:		Line 78:

	This will make it launch a virtual machine on boot.		This will make it launch a virtual machine on boot.

			[[Category:Virtualization]]

imported>Kisik21: Oops. We're not writing C, single-line comments are not //

2019-08-01T06:12:09Z

Oops. We're not writing C, single-line comments are not //

← Older revision		Revision as of 06:12, 1 August 2019
Line 7:		Line 7:
	but I don't use it here, because we need another kind of derivation. */		but I don't use it here, because we need another kind of derivation. */
	nixosVM = configuration: (import <nixpkgs/nixos> { inherit configuration; }).vm;		nixosVM = configuration: (import <nixpkgs/nixos> { inherit configuration; }).vm;
	// This is a convenience for having the machine configurations.		# This is a convenience for having the machine configurations.
	vms = {		vms = {
	// You can write it inline...		# You can write it inline...
	yuki = { config, pkgs, lib, ... }: {		yuki = { config, pkgs, lib, ... }: {
	services.httpd.enable = true;		services.httpd.enable = true;
	services.httpd.adminAddr = "webmaster@example.com";		services.httpd.adminAddr = "webmaster@example.com";
	};		};
	// Or import from another file.		# Or import from another file.
	sakura = import VMs/sakura.nix;		sakura = import VMs/sakura.nix;
	};		};
	in {		in {
	environment.systemPackages = [		environment.systemPackages = [
	// Then just add it like this!		# Then just add it like this!
	(nixosVM vms.yuki)		(nixosVM vms.yuki)
	];		];

imported>Kisik21: Added "restartIfChanged" parameter to allow VMs to be not restarted on configuration change

2019-07-27T01:00:42Z

Added "restartIfChanged" parameter to allow VMs to be not restarted on configuration change

← Older revision		Revision as of 01:00, 27 July 2019
Line 48:		Line 48:
	network_options ? "",		network_options ? "",
	args ? "",		args ? "",
	diskimagefolder ? "/var/lib/nixos-vms" }:		diskimagefolder ? "/var/lib/nixos-vms",
			restartIfChanged ? true }:
	let		let
	nixos-system = configuration: (import <nixpkgs/nixos> { inherit configuration; });		nixos-system = configuration: (import <nixpkgs/nixos> { inherit configuration; });
Line 55:		Line 56:
	in {		in {
	systemd.services.${hostname} = {		systemd.services.${hostname} = {
	inherit after;		inherit after restartIfChanged;
	environment = {		environment = {
	QEMU_NET_OPTS = network_options;		QEMU_NET_OPTS = network_options;

imported>Kisik21: Described a way to launch NixOS VMs on boot with only Nix

2019-07-27T00:35:54Z

Described a way to launch NixOS VMs on boot with only Nix

New page

A NixOS VM built with <code>nixos-rebuild build-vm</code> is just another derivation. It can be even installed in a NixOS system's PATH by adapting the following snippet:

<syntaxhighlight lang="nix">
{ config, pkgs, lib, ... }:
let
/* nixosVM is syntactic sugar for calling this. There is pkgs.nixos in the nixpkgs,
but I don't use it here, because we need another kind of derivation. */
nixosVM = configuration: (import <nixpkgs/nixos> { inherit configuration; }).vm;
// This is a convenience for having the machine configurations.
vms = {
// You can write it inline...
yuki = { config, pkgs, lib, ... }: {
services.httpd.enable = true;
services.httpd.adminAddr = "webmaster@example.com";
};
// Or import from another file.
sakura = import VMs/sakura.nix;
};
in {
environment.systemPackages = [
// Then just add it like this!
(nixosVM vms.yuki)
];
}
</syntaxhighlight>
To launch a VM automatically, a systemd service can be employed.
<syntaxhighlight lang="nix">
systemd.services.yuki-vm = {
after = [ "network.target" ];
path = [ (nixosVM vms.yuki) ];
script = "run-*-vm";
environment = {
QEMU_NET_OPTS = "hostfwd=tcp::8022-:22";
NIX_DISK_IMAGE = "/var/lib/vms/yuki.qcow2";
QEMU_OPTS = "-m 1024M";
};
scriptArgs = "";
};
</syntaxhighlight>

There is area for improvement, such as wrapping it in a module generating these on the fly.

The following Nix function dynamically generates a systemd service for a NixOS VM.
<syntaxhighlight lang="nix">
{ configuration,
after ? [ "network.target" ],
memory ? "384M",
network_options ? "",
args ? "",
diskimagefolder ? "/var/lib/nixos-vms" }:
let
nixos-system = configuration: (import <nixpkgs/nixos> { inherit configuration; });
hostname = (nixos-system configuration).config.networking.hostName;
nixos-vm = (nixos-system configuration).vm;
in {
systemd.services.${hostname} = {
inherit after;
environment = {
QEMU_NET_OPTS = network_options;
QEMU_ARGS = "${args} -m ${memory}";
NIX_DISK_IMAGE = "${diskimagefolder}/${hostname}.qcow2";
};
script = "run-${hostname}-vm";
};
}
</syntaxhighlight>

This can be used like this:
<syntaxhighlight lang="nix">
{ config, pkgs, lib, ... }:
{
imports = [
(./nixos-vm-service.nix { configuration = (import vms/yuki.nix); memory = "1024M"; })
];
}
</syntaxhighlight>

This will make it launch a virtual machine on boot.