.Dd January 1, 1980
.Dt nixos-install 8
.Os
.Sh NAME
.Nm nixos-install
.Nd install bootloader and NixOS
.
.
.
.Sh SYNOPSIS
.Nm nixos-install
.Op Fl -verbose | v
.Op Fl I Ar path
.Op Fl -root Ar root
.Op Fl -system Ar path
.Op Fl -flake Ar flake-uri
.Op Fl -impure
.Op Fl -channel Ar channel
.Op Fl -no-channel-copy
.Op Fl -no-root-password | -no-root-passwd
.Op Fl -no-bootloader
.Op Fl -max-jobs | j Ar number
.Op Fl -cores Ar number
.Op Fl -option Ar name value
.Op Fl -show-trace
.Op Fl -keep-going
.Op Fl -help
.
.
.
.Sh DESCRIPTION
This command installs NixOS in the file system mounted on
.Pa /mnt Ns
, based on the NixOS configuration specified in
.Pa /mnt/etc/nixos/configuration.nix Ns
\&. It performs the following steps:
.
.Bl -enum
.It
It copies Nix and its dependencies to
.Pa /mnt/nix/store Ns
\&.
.
.It
It runs Nix in
.Pa /mnt
to build the NixOS configuration specified in
.Pa /mnt/etc/nixos/configuration.nix Ns
\&.
.
.It
It installs the current channel
.Dq nixos
in the target channel profile (unless
.Fl -no-channel-copy
is specified).
.
.It
It installs the GRUB boot loader on the device specified in the option
.Va boot.loader.grub.device
(unless
.Fl -no-bootloader
is specified), and generates a GRUB configuration file that boots into the NixOS
configuration just installed.
.
.It
It prompts you for a password for the root account (unless
.Fl -no-root-password
is specified).
.El
.
.Pp
This command is idempotent: if it is interrupted or fails due to a temporary
problem (e.g. a network issue), you can safely re-run it.
.
.
.
.Sh OPTIONS
.Bl -tag -width indent
.It Fl -verbose , v
Increases the level of verbosity of diagnostic messages printed on standard
error. For each Nix operation, the information printed on standard output is
well-defined; any diagnostic information is printed on standard error, never on
standard output.
.Pp
Please note that this option may be specified repeatedly.
.
.It Fl -root Ar root
Defaults to
.Pa /mnt Ns
\&. If this option is given, treat the directory
.Ar root
as the root of the NixOS installation.
.
.It Fl -system Ar path
If this option is provided,
.Nm
will install the specified closure rather than attempt to build one from
.Pa /mnt/etc/nixos/configuration.nix Ns
\&.
.Pp
The closure must be an appropriately configured NixOS system, with boot loader
and partition configuration that fits the target host. Such a closure is
typically obtained with a command such as
.Ic nix-build -I nixos-config=./configuration.nix '<nixpkgs/nixos>' -A system --no-out-link Ns
\&.
.
.It Fl -flake Ar flake-uri Ns # Ns Ar name
Build the NixOS system from the specified flake. The flake must contain an
output named
.Ql nixosConfigurations. Ns Ar name Ns
\&.
.
.It Fl -channel Ar channel
If this option is provided, do not copy the current
.Dq nixos
channel to the target host. Instead, use the specified derivation.
.
.It Fl I Ar Path
Add a path to the Nix expression search path. This option may be given multiple
times. See the
.Ev NIX_PATH
environment variable for information on the semantics of the Nix search path. Paths added through
.Fl I
take precedence over
.Ev NIX_PATH Ns
\&.
.
.It Fl -max-jobs , j Ar number
Sets the maximum number of build jobs that Nix will perform in parallel to the
specified number. The default is 1. A higher value is useful on SMP systems or
to exploit I/O latency.
.
.It Fl -cores Ar N
Sets the value of the
.Ev NIX_BUILD_CORES
environment variable in the invocation of builders. Builders can use this
variable at their discretion to control the maximum amount of parallelism. For
instance, in Nixpkgs, if the derivation attribute
.Va enableParallelBuilding
is set to true, the builder passes the
.Fl j Ns Va N
flag to GNU Make. The value 0 means that the builder should use all available CPU cores in the system.
.
.It Fl -option Ar name value
Set the Nix configuration option
.Ar name
to
.Ar value Ns
\&.
.
.It Fl -show-trace
Causes Nix to print out a stack trace in case of Nix expression evaluation errors.
.
.It Fl -keep-going
Causes Nix to continue building derivations as far as possible in the face of failed builds.
.
.It Fl -help
Synonym for
.Ic man nixos-install Ns
\&.
.El
.
.
.
.Sh EXAMPLES
A typical NixOS installation is done by creating and mounting a file system on
.Pa /mnt Ns
, generating a NixOS configuration in
.Pa /mnt/etc/nixos/configuration.nix Ns
, and running
.Nm Ns
\&. For instance, if we want to install NixOS on an ext4 file system created in
.Pa /dev/sda1 Ns
:
.Bd -literal -offset indent
$ mkfs.ext4 /dev/sda1
$ mount /dev/sda1 /mnt
$ nixos-generate-config --root /mnt
$ # edit /mnt/etc/nixos/configuration.nix
$ nixos-install
$ reboot
.Ed
.
.
.
.Sh AUTHORS
.An -nosplit
.An Eelco Dolstra
and
.An the Nixpkgs/NixOS contributors