nixos-generate-config8NixOSnixos-generate-configgenerate NixOS configuration modulesnixos-generate-configrootdirDescriptionThis command writes two NixOS configuration modules:
This module sets NixOS configuration options based on your
current hardware configuration. In particular, it sets the
option to reflect all currently
mounted file systems, the option to
reflect active swap devices, and the
options to ensure that the
initial ramdisk contains any kernel modules necessary for
mounting the root file system.If this file already exists, it is overwritten. Thus, you
should not modify it manually. Rather, you should include it
from your /etc/nixos/configuration.nix, and
re-run nixos-generate-config to update it
whenever your hardware configuration changes.This is the main NixOS system configuration module. If it
already exists, it’s left unchanged. Otherwise,
nixos-generate-config will write a template
for you to customise.OptionsThis command accepts the following options:If this option is given, treat the directory
root as the root of the file system.
This means that configuration files will be written to
root/etc/nixos,
and that any file systems outside of
root are ignored for the purpose of
generating the option.If this option is given, write the configuration files to
the directory dir instead of
/etc/nixos.Overwrite
/etc/nixos/configuration.nix if it already
exists.Omit everything concerning file system information
(which includes swap devices) from the hardware configuration.Don't generate configuration.nix or
hardware-configuration.nix and print the
hardware configuration to stdout only.ExamplesThis command is typically used during NixOS installation to
write initial configuration modules. For example, if you created and
mounted the target file systems on /mnt and
/mnt/boot, you would run:
$ nixos-generate-config --root /mnt
The resulting file
/mnt/etc/nixos/hardware-configuration.nix might
look like this:
# Do not modify this file! It was generated by ‘nixos-generate-config’
# and may be overwritten by future invocations. Please make changes
# to /etc/nixos/configuration.nix instead.
{ config, pkgs, ... }:
{
imports =
[ <nixos/modules/installer/scan/not-detected.nix>
];
boot.initrd.availableKernelModules = [ "ehci_hcd" "ahci" ];
boot.kernelModules = [ "kvm-intel" ];
boot.extraModulePackages = [ ];
fileSystems."/" =
{ device = "/dev/disk/by-label/nixos";
fsType = "ext3";
options = [ "rw" "data=ordered" "relatime" ];
};
fileSystems."/boot" =
{ device = "/dev/sda1";
fsType = "ext3";
options = [ "rw" "errors=continue" "user_xattr" "acl" "barrier=1" "data=writeback" "relatime" ];
};
swapDevices =
[ { device = "/dev/sda2"; }
];
nix.maxJobs = 8;
}
It will also create a basic
/mnt/etc/nixos/configuration.nix, which you
should edit to customise the logical configuration of your system.
This file includes the result of the hardware scan as follows:
imports = [ ./hardware-configuration.nix ];
After installation, if your hardware configuration changes, you
can run:
$ nixos-generate-config
to update /etc/nixos/hardware-configuration.nix.
Your /etc/nixos/configuration.nix will
not be overwritten.