Next: operating-system Reference, Up: Configuração do sistema [Contents][Index]
The operating system is configured by providing an operating-system
declaration in a file that can then be passed to the guix system
command (see Invoking guix system). A simple setup, with the default
system services, the default Linux-Libre kernel, initial RAM disk, and boot
loader looks like this:
;; This is an operating system configuration template ;; for a "bare bones" setup, with no X11 display server. (use-modules (gnu)) (use-service-modules networking ssh) (use-package-modules screen ssh) (operating-system (host-name "komputilo") (timezone "Europe/Berlin") (locale "en_US.utf8") ;; Boot in "legacy" BIOS mode, assuming /dev/sdX is the ;; target hard disk, and "my-root" is the label of the target ;; root file system. (bootloader (bootloader-configuration (bootloader grub-bootloader) (targets '("/dev/sdX")))) ;; It's fitting to support the equally bare bones ‘-nographic’ ;; QEMU option, which also nicely sidesteps forcing QWERTY. (kernel-arguments (list "console=ttyS0,115200")) (file-systems (cons (file-system (device (file-system-label "my-root")) (mount-point "/") (type "ext4")) %base-file-systems)) ;; This is where user accounts are specified. The "root" ;; account is implicit, and is initially created with the ;; empty password. (users (cons (user-account (name "alice") (comment "Bob's sister") (group "users") ;; Adding the account to the "wheel" group ;; makes it a sudoer. Adding it to "audio" ;; and "video" allows the user to play sound ;; and access the webcam. (supplementary-groups '("wheel" "audio" "video"))) %base-user-accounts)) ;; Globally-installed packages. (packages (cons screen %base-packages)) ;; Add services to the baseline: a DHCP client and ;; an SSH server. (services (append (list (service dhcp-client-service-type) (service openssh-service-type (openssh-configuration (openssh openssh-sans-x) (port-number 2222)))) %base-services)))
Este exemplo deve ser autodescritivo. Alguns dos campos definidos acima,
como host-name e bootloader, são obrigatórios. Outros, como
packages e services, podem ser omitidos; nesse caso, eles
recebem um valor padrão.
Below we discuss the effect of some of the most important fields
(see operating-system Reference, for details about all the available
fields), and how to instantiate the operating system using
guix system.
The bootloader field describes the method that will be used to boot
your system. Machines based on Intel processors can boot in “legacy” BIOS
mode, as in the example above. However, more recent machines rely instead
on the Unified Extensible Firmware Interface (UEFI) to boot. In that
case, the bootloader field should contain something along these
lines:
(bootloader-configuration
(bootloader grub-efi-bootloader)
(targets '("/boot/efi")))
See Configuração do carregador de inicialização, for more information on the available configuration options.
The packages field lists packages that will be globally visible on
the system, for all user accounts—i.e., in every user’s PATH
environment variable—in addition to the per-user profiles (see Invocando guix package). The %base-packages variable provides all the tools
one would expect for basic user and administrator tasks—including the GNU
Core Utilities, the GNU Networking Utilities, the mg lightweight
text editor, find, grep, etc. The example above adds
GNU Screen to those, taken from the (gnu packages screen) module
(see Módulos de pacote). The (list package output) syntax can be
used to add a specific output of a package:
(use-modules (gnu packages)) (use-modules (gnu packages dns)) (operating-system ;; ... (packages (cons (list isc-bind "utils") %base-packages)))
Referring to packages by variable name, like isc-bind above, has the
advantage of being unambiguous; it also allows typos and such to be
diagnosed right away as “unbound variables”. The downside is that one
needs to know which module defines which package, and to augment the
use-package-modules line accordingly. To avoid that, one can use the
specification->package procedure of the (gnu packages) module,
which returns the best package for a given name or name and version:
(use-modules (gnu packages)) (operating-system ;; ... (packages (append (map specification->package '("tcpdump" "htop" "gnupg@2.0")) %base-packages)))
The services field lists system services to be made available
when the system starts (see Serviços). The operating-system
declaration above specifies that, in addition to the basic services, we want
the OpenSSH secure shell daemon listening on port 2222 (see openssh-service-type). Under the hood,
openssh-service-type arranges so that sshd is started with
the right command-line options, possibly with supporting configuration files
generated as needed (see Definindo serviços).
Occasionally, instead of using the base services as is, you will want to
customize them. To do this, use modify-services (see modify-services) to modify the list.
For example, suppose you want to modify guix-daemon and Mingetty (the
console log-in) in the %base-services list (see %base-services). To do that, you can write the following in your
operating system declaration:
(define %my-services ;; My very own list of services. (modify-services %base-services (guix-service-type config => (guix-configuration (inherit config) ;; Fetch substitutes from example.org. (substitute-urls (list "https://example.org/guix" "https://ci.guix.gnu.org")))) (mingetty-service-type config => (mingetty-configuration (inherit config) ;; Automatically log in as "guest". (auto-login "guest"))))) (operating-system ;; … (services %my-services))
This changes the configuration—i.e., the service parameters—of the
guix-service-type instance, and that of all the
mingetty-service-type instances in the %base-services list
(see see the cookbook for how to auto-login
one user to a specific TTY in GNU Guix Cookbook)). Observe
how this is accomplished: first, we arrange for the original configuration
to be bound to the identifier config in the body, and then we
write the body so that it evaluates to the desired configuration. In
particular, notice how we use inherit to create a new configuration
which has the same values as the old configuration, but with a few
modifications.
The configuration for a typical “desktop” usage, with an encrypted root partition, a swap file on the root partition, the X11 display server, GNOME and Xfce (users can choose which of these desktop environments to use at the log-in screen by pressing F1), network management, power management, and more, would look like this:
;; This is an operating system configuration template ;; for a "desktop" setup with GNOME and Xfce where the ;; root partition is encrypted with LUKS, and a swap file. (use-modules (gnu) (gnu system nss) (guix utils)) (use-service-modules desktop sddm xorg) (use-package-modules certs gnome) (operating-system (host-name "antelope") (timezone "Europe/Paris") (locale "en_US.utf8") ;; Choose US English keyboard layout. The "altgr-intl" ;; variant provides dead keys for accented characters. (keyboard-layout (keyboard-layout "us" "altgr-intl")) ;; Use the UEFI variant of GRUB with the EFI System ;; Partition mounted on /boot/efi. (bootloader (bootloader-configuration (bootloader grub-efi-bootloader) (targets '("/boot/efi")) (keyboard-layout keyboard-layout))) ;; Specify a mapped device for the encrypted root partition. ;; The UUID is that returned by 'cryptsetup luksUUID'. (mapped-devices (list (mapped-device (source (uuid "12345678-1234-1234-1234-123456789abc")) (target "my-root") (type luks-device-mapping)))) (file-systems (append (list (file-system (device (file-system-label "my-root")) (mount-point "/") (type "ext4") (dependencies mapped-devices)) (file-system (device (uuid "1234-ABCD" 'fat)) (mount-point "/boot/efi") (type "vfat"))) %base-file-systems)) ;; Specify a swap file for the system, which resides on the ;; root file system. (swap-devices (list (swap-space (target "/swapfile")))) ;; Create user `bob' with `alice' as its initial password. (users (cons (user-account (name "bob") (comment "Alice's brother") (password (crypt "alice" "$6$abc")) (group "students") (supplementary-groups '("wheel" "netdev" "audio" "video"))) %base-user-accounts)) ;; Add the `students' group (groups (cons* (user-group (name "students")) %base-groups)) ;; This is where we specify system-wide packages. (packages (append (list ;; for HTTPS access nss-certs ;; for user mounts gvfs) %base-packages)) ;; Add GNOME and Xfce---we can choose at the log-in screen ;; by clicking the gear. Use the "desktop" services, which ;; include the X11 log-in service, networking with ;; NetworkManager, and more. (services (if (target-x86-64?) (append (list (service gnome-desktop-service-type) (service xfce-desktop-service-type) (set-xorg-configuration (xorg-configuration (keyboard-layout keyboard-layout)))) %desktop-services) ;; FIXME: Since GDM depends on Rust (gdm -> gnome-shell -> gjs ;; -> mozjs -> rust) and Rust is currently unavailable on ;; non-x86_64 platforms, we use SDDM and Mate here instead of ;; GNOME and GDM. (append (list (service mate-desktop-service-type) (service xfce-desktop-service-type) (set-xorg-configuration (xorg-configuration (keyboard-layout keyboard-layout)) sddm-service-type)) %desktop-services))) ;; Allow resolution of '.local' host names with mDNS. (name-service-switch %mdns-host-lookup-nss))
Um sistema gráfico com uma escolha de gerenciadores de janelas leves em vez de ambientes de desktop completos teria a seguinte aparência:
;; This is an operating system configuration template ;; for a "desktop" setup without full-blown desktop ;; environments. (use-modules (gnu) (gnu system nss)) (use-service-modules desktop) (use-package-modules bootloaders certs emacs emacs-xyz ratpoison suckless wm xorg) (operating-system (host-name "antelope") (timezone "Europe/Paris") (locale "en_US.utf8") ;; Use the UEFI variant of GRUB with the EFI System ;; Partition mounted on /boot/efi. (bootloader (bootloader-configuration (bootloader grub-efi-bootloader) (targets '("/boot/efi")))) ;; Assume the target root file system is labelled "my-root", ;; and the EFI System Partition has UUID 1234-ABCD. (file-systems (append (list (file-system (device (file-system-label "my-root")) (mount-point "/") (type "ext4")) (file-system (device (uuid "1234-ABCD" 'fat)) (mount-point "/boot/efi") (type "vfat"))) %base-file-systems)) (users (cons (user-account (name "alice") (comment "Bob's sister") (group "users") (supplementary-groups '("wheel" "netdev" "audio" "video"))) %base-user-accounts)) ;; Add a bunch of window managers; we can choose one at ;; the log-in screen with F1. (packages (append (list ;; window managers ratpoison i3-wm i3status dmenu emacs emacs-exwm emacs-desktop-environment ;; terminal emulator xterm ;; for HTTPS access nss-certs) %base-packages)) ;; Use the "desktop" services, which include the X11 ;; log-in service, networking with NetworkManager, and more. (services %desktop-services) ;; Allow resolution of '.local' host names with mDNS. (name-service-switch %mdns-host-lookup-nss))
Este exemplo faz referência ao sistema de arquivos /boot/efi por seu
UUID, 1234-ABCD. Substitua esse UUID pelo UUID correto no seu
sistema, conforme retornado pelo comando blkid.
See Serviços de desktop, for the exact list of services provided by
%desktop-services. See Certificados X.509, for background
information about the nss-certs package that is used here.
Again, %desktop-services is just a list of service objects. If you
want to remove services from there, you can do so using the procedures for
list filtering (see SRFI-1 Filtering and Partitioning in GNU Guile
Reference Manual). For instance, the following expression returns a list
that contains all the services in %desktop-services minus the Avahi
service:
(remove (lambda (service)
(eq? (service-kind service) avahi-service-type))
%desktop-services)
Alternatively, the modify-services macro can be used:
(modify-services %desktop-services
(delete avahi-service-type))
Assuming the operating-system declaration is stored in the
my-system-config.scm file, the guix system reconfigure
my-system-config.scm command instantiates that configuration, and makes it
the default GRUB boot entry (see Invoking guix system).
Nota: We recommend that you keep this my-system-config.scm file safe and under version control to easily track changes to your configuration.
The normal way to change the system configuration is by updating this file
and re-running guix system reconfigure. One should never have to
touch files in /etc or to run commands that modify the system state
such as useradd or grub-install. In fact, you must
avoid that since that would not only void your warranty but also prevent you
from rolling back to previous versions of your system, should you ever need
to.
Speaking of roll-back, each time you run guix system reconfigure,
a new generation of the system is created—without modifying or
deleting previous generations. Old system generations get an entry in the
bootloader boot menu, allowing you to boot them in case something went wrong
with the latest generation. Reassuring, no? The guix system
list-generations command lists the system generations available on disk.
It is also possible to roll back the system via the commands guix
system roll-back and guix system switch-generation.
Although the guix system reconfigure command will not modify
previous generations, you must take care when the current generation is not
the latest (e.g., after invoking guix system roll-back), since the
operation might overwrite a later generation (see Invoking guix system).
At the Scheme level, the bulk of an operating-system declaration is
instantiated with the following monadic procedure (see A mônada do armazém):
Return a derivation that builds os, an operating-system object
(see Derivações).
The output of the derivation is a single directory that refers to all the packages, configuration files, and other supporting files needed to instantiate os.
This procedure is provided by the (gnu system) module. Along with
(gnu services) (see Serviços), this module contains the guts of
Guix System. Make sure to visit it!
Next: operating-system Reference, Up: Configuração do sistema [Contents][Index]