334 lines
11 KiB
Markdown
334 lines
11 KiB
Markdown
---
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title:
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Nixos
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sidebar: true
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misc_links: >-
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<a href="set_up_build_environments.md" target="_blank">Set up build environments</a>.<br>
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<a href="wireguard.html" target="_blank">Wireguard</a>.<br>
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<a href="dovecot.html" target="_blank">Dovecot</a>.<br>
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abstract: >-
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I know nothing about nix. This file exists to record my learning
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experience.\
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\
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The plan is to be able to install nix on debian, then load a reproducible
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configuration file so that I can instantly and reproducibly produce a
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host setup the way I want it.
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...
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Nixos is primarily a package manager with a declarative functional language as its package manager.
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Which makes it possible to reproducibly create a setup. Unfortunately the packages are hard to customise, because access to the
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configuration files is restricted and non trivial -- you have to create your own package.
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Nixos solves the problem of dll hell by having any number of configurations living on the same machine -- which leads to massive and rapid accumulation of garbage. Garbage collection is very slow, and requires either a lot of ram or a lot of swap (12GB swap recommended. This is a feature I do not want, but wind up suffering, for the advantage of reproducible setups.
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To avoid bloat, can use a strategy of re-install from scratch, which Nixos makes less painful. I notice the mail server insists
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on pinning to a specific Nixos release.
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# Install Nixos
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On linux running systemd, with SELinux disabled, with curl, as root
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```bash
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bash <(curl -L https://nixos.org/nix/install) --daemon
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```
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log off, then open a new terminal
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```bash
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nix-shell -p nix-info --run "nix-info -m"
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```
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You can open an issue at
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https://github.com/NixOS/nix/issues/new?labels=installer&template=installer.md
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Or get in touch with the community: https://nixos.org/community
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# minimal server
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This describes nixos, which I would like to use, but probably cannot
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be conveniently installed in a hosting service.
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ssh and avahi daemon, pubkeys setup for ssh, users created.
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## configuration.nix
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```nix
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# Edit this configuration file to define what should be installed on
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# your system. Help is available in the configuration.nix(5) man page, on
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# https://search.nixos.org/options and in the NixOS manual (`nixos-help`).
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{ config, lib, pkgs, ... }:
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{
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imports =
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[ # Include the results of the hardware scan.
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./hardware-configuration.nix
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];
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# Use the systemd-boot EFI boot loader.
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boot.loader.systemd-boot.enable = true;
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boot.loader.efi.canTouchEfiVariables = true;
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# networking.hostName = "nixos"; # Define your hostname.
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# Pick only one of the below networking options.
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# networking.wireless.enable = true; # Enables wireless support via wpa_supplicant.
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# networking.networkmanager.enable = true; # Easiest to use and most distros use this by default.
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# Set your time zone.
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# time.timeZone = "Europe/Amsterdam";
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# Configure network proxy if necessary
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# networking.proxy.default = "http://user:password@proxy:port/";
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# networking.proxy.noProxy = "127.0.0.1,localhost,internal.domain";
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# Select internationalisation properties.
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i18n.defaultLocale = "en_US.UTF-8";
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# console = {
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# font = "Lat2-Terminus16";
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# keyMap = "us";
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# useXkbConfig = true; # use xkb.options in tty.
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# };
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# Enable the X11 windowing system.
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# services.xserver.enable = true;
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# Configure keymap in X11
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# services.xserver.xkb.layout = "us";
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# services.xserver.xkb.options = "eurosign:e,caps:escape";
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# Enable CUPS to print documents.
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# services.printing.enable = true;
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# Enable sound.
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# hardware.pulseaudio.enable = true;
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# OR
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# services.pipewire = {
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# enable = true;
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# pulse.enable = true;
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# };
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# Enable touchpad support (enabled default in most desktopManager).
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services.libinput.enable = false;
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#enable avahi-daemon
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services.avahi = {
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enable = true;
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ipv6 = true;
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ipv4 = true;
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publish = {
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enable = true;
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addresses = true;
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};
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# nssmdns4 = true;
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};
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# guest additions
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# not very useful unless desktop enabled, or maybe it just does not work at all
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#virtualisation.virtualbox.guest.enable = true;
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# Define a user account. Don't forget to set a password with ‘passwd’.
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users.users.cherry = {
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isNormalUser = true;
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extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
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openssh.authorizedKeys.keys = [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAVcyLSWwsa8aN+v2PaS1wuHXGVhTdC+43B3eZ9j/C/M" ];
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# packages = with pkgs; [
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# firefox
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# tree
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# ];
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};
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# Define a user account. Don't forget to set a password with ‘passwd’.
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users.users.root = {
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openssh.authorizedKeys.keys = [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAVcyLSWwsa8aN+v2PaS1wuHXGVhTdC+43B3eZ9j/C/M" ];
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};
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# List packages installed in system profile. To search, run:
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# $ nix search wget
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# environment.systemPackages = with pkgs; [
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# vim # Do not forget to add an editor to edit configuration.nix! The Nano editor is also installed by default.
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# wget
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# ];
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# Some programs need SUID wrappers, can be configured further or are
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# started in user sessions.
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# programs.mtr.enable = true;
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# programs.gnupg.agent = {
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# enable = true;
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# enableSSHSupport = true;
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# };
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# List services that you want to enable:
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# Enable the OpenSSH daemon.
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services.openssh = {
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enable = true;
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hostKeys = [
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{
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path = "/etc/ssh/ssh_host_ed25519_key";
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rounds = 100;
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type = "ed25519";
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}
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];
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settings = {
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PasswordAuthentication = false;
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PubkeyAuthentication = true;
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PermitRootLogin = "prohibit-password";
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UsePAM = false;
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ChallengeResponseAuthentication = false;
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Ciphers = [ "chacha20-poly1305@openssh.com" ];
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GatewayPorts = "Yes";
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KbdInteractiveAuthentication = false;
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KexAlgorithms = [ "curve25519-sha256" "curve25519-sha256@libssh.org" ];
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Macs = [ "hmac-sha2-256-etm@openssh.com" ];
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};
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};
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# Open ports in the firewall.
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# networking.firewall.allowedTCPPorts = [ ... ];
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# networking.firewall.allowedUDPPorts = [ ... ];
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# Or disable the firewall altogether.
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networking.firewall.enable = false;
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# Copy the NixOS configuration file and link it from the resulting system
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# (/run/current-system/configuration.nix). This is useful in case you
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# accidentally delete configuration.nix.
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# system.copySystemConfiguration = true;
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# This option defines the first version of NixOS you have installed on this particular machine,
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# and is used to maintain compatibility with application data (e.g. databases) created on older NixOS versions.
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#
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# Most users should NEVER change this value after the initial install, for any reason,
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# even if you've upgraded your system to a new NixOS release.
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#
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# This value does NOT affect the Nixpkgs version your packages and OS are pulled from,
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# so changing it will NOT upgrade your system - see https://nixos.org/manual/nixos/stable/#sec-upgrading for how
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# to actually do that.
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#
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# This value being lower than the current NixOS release does NOT mean your system is
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# out of date, out of support, or vulnerable.
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#
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# Do NOT change this value unless you have manually inspected all the changes it would make to your configuration,
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# and migrated your data accordingly.
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#
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# For more information, see `man configuration.nix` or https://nixos.org/manual/nixos/stable/options#opt-system.stateVersion .
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system.stateVersion = "24.05"; # Did you read the comment?
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}
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```
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## hardware-configuration.nix
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This should be set up automatically by the install
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process. For a human to do it is very difficult.
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```nix
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{
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imports = [ ];
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boot.initrd.availableKernelModules = [ "ata_piix" "ohci_pci" "ehci_pci" "ahci" "sd_mod" "sr_mod" ];
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boot.initrd.kernelModules = [ ];
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boot.kernelModules = [ ];
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boot.extraModulePackages = [ ];
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fileSystems."/" =
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{ device = "/dev/disk/by-uuid/bf0ee7f8-0397-44d6-a3f7-462b848d0912";
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fsType = "ext4";
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};
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fileSystems."/boot" =
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{ device = "/dev/disk/by-uuid/B4E2-93D5";
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fsType = "vfat";
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options = [ "fmask=0077" "dmask=0077" ];
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};
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swapDevices =
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[ { device = "/dev/disk/by-uuid/2b67021b-3b31-4e2d-a521-05362ffb39f8"; }
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];
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# Enables DHCP on each ethernet and wireless interface. In case of scripted networking
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# (the default) this is the recommended approach. When using systemd-networkd it's
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# still possible to use this option, but it's recommended to use it in conjunction
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# with explicit per-interface declarations with `networking.interfaces.<interface>.useDHCP`.
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networking.useDHCP = lib.mkDefault true;
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# networking.interfaces.enp0s3.useDHCP = lib.mkDefault true;
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nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
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virtualisation.virtualbox.guest.enable = true;
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}
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```
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# change config
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```bash
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nano /etc/nixos/conf*.nix
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df -h .
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nixos-rebuild test
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nixos-rebuild boot
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df -h .
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```
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## garbage collect old configs
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```bash
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nix-env --delete-generations old
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nix-store --gc --print-dead
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nix-store --gc --print-live
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nix-store --gc
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```
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# Install nginx, mariadb, and php
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[Nginx setup](https://wiki.nixos.org/wiki/Nginx#LEMP_stack)
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# Nixos mail server
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[This](https://nixos-mailserver.readthedocs.io/en/latest/) has the huge advantage that it only needs a small computer.
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Setup is also decribed as ridiculously easy -- compare and contrast with much grief while setting up on debian.
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And the huge disadvantage that it only exists for Nix 23.05, while the latest "stable" (not very stable at all) release is 24.05
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It also has only a minimal nginx setup. Not at all sure what will happen when I combine it with a real nginx setup.
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We have to pin to a particular release: The following code is an example of such pinning
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```nix
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{ config, pkgs, ... }: {
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imports = [
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# builtins.fetchTarbll pins Nixos to a particular release, prevents the lastest release (24.05)from being default installed.
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(builtins.fetchTarball {
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# Pick a release version you are interested in and set its hash, e.g.
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url = "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/nixos-23.05/nixos-mailserver-nixos-23.05.tar.gz";
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# To get the sha256 of the nixos-mailserver tarball, we can use the nix-prefetch-url command:
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# release="nixos-23.05"; nix-prefetch-url "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/${release}/nixos-mailserver-${release}.tar.gz" --unpack
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sha256 = "0000000000000000000000000000000000000000000000000000";
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})
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];
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mailserver = {
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enable = true;
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fqdn = "mail.example.com";
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domains = [ "example.com" ];
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# A list of all login accounts. To create the password hashes, use
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# nix-shell -p mkpasswd --run 'mkpasswd -sm bcrypt'
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loginAccounts = {
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"user1@example.com" = {
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hashedPasswordFile = "/a/file/containing/a/hashed/password";
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aliases = ["postmaster@example.com"];
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};
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"user2@example.com" = { ... };
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};
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# Use Let's Encrypt certificates. Note that this needs to set up a stripped
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# down nginx and opens port 80.
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certificateScheme = "acme-nginx";
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};
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security.acme.acceptTerms = true;
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security.acme.defaults.email = "security@example.com";
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}
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```
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