diff --git a/nixos/modules/config/nix-channel.nix b/nixos/modules/config/nix-channel.nix new file mode 100644 index 000000000000..557f17d8b3b7 --- /dev/null +++ b/nixos/modules/config/nix-channel.nix @@ -0,0 +1,70 @@ +/* + Manages the things that are needed for a traditional nix-channel based + configuration to work. + + See also + - ./nix.nix + - ./nix-flakes.nix + */ +{ config, lib, ... }: +let + inherit (lib) + mkIf + mkOption + stringAfter + types + ; + + cfg = config.nix; + +in +{ + options = { + nix = { + nixPath = mkOption { + type = types.listOf types.str; + default = [ + "nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixos" + "nixos-config=/etc/nixos/configuration.nix" + "/nix/var/nix/profiles/per-user/root/channels" + ]; + description = lib.mdDoc '' + The default Nix expression search path, used by the Nix + evaluator to look up paths enclosed in angle brackets + (e.g. ``). + ''; + }; + }; + + system = { + defaultChannel = mkOption { + internal = true; + type = types.str; + default = "https://nixos.org/channels/nixos-unstable"; + description = lib.mdDoc "Default NixOS channel to which the root user is subscribed."; + }; + }; + }; + + config = mkIf cfg.enable { + + environment.extraInit = + '' + if [ -e "$HOME/.nix-defexpr/channels" ]; then + export NIX_PATH="$HOME/.nix-defexpr/channels''${NIX_PATH:+:$NIX_PATH}" + fi + ''; + + environment.sessionVariables = { + NIX_PATH = cfg.nixPath; + }; + + system.activationScripts.nix-channel = stringAfter [ "etc" "users" ] + '' + # Subscribe the root user to the NixOS channel by default. + if [ ! -e "/root/.nix-channels" ]; then + echo "${config.system.defaultChannel} nixos" > "/root/.nix-channels" + fi + ''; + }; +} diff --git a/nixos/modules/config/nix-flakes.nix b/nixos/modules/config/nix-flakes.nix new file mode 100644 index 000000000000..242d8d3b82b7 --- /dev/null +++ b/nixos/modules/config/nix-flakes.nix @@ -0,0 +1,95 @@ +/* + Manages the flake registry. + + See also + - ./nix.nix + - ./nix-channel.nix + */ +{ config, lib, ... }: +let + inherit (lib) + filterAttrs + literalExpression + mapAttrsToList + mkDefault + mkIf + mkOption + types + ; + + cfg = config.nix; + +in +{ + options = { + nix = { + registry = mkOption { + type = types.attrsOf (types.submodule ( + let + referenceAttrs = with types; attrsOf (oneOf [ + str + int + bool + path + package + ]); + in + { config, name, ... }: + { + options = { + from = mkOption { + type = referenceAttrs; + example = { type = "indirect"; id = "nixpkgs"; }; + description = lib.mdDoc "The flake reference to be rewritten."; + }; + to = mkOption { + type = referenceAttrs; + example = { type = "github"; owner = "my-org"; repo = "my-nixpkgs"; }; + description = lib.mdDoc "The flake reference {option}`from` is rewritten to."; + }; + flake = mkOption { + type = types.nullOr types.attrs; + default = null; + example = literalExpression "nixpkgs"; + description = lib.mdDoc '' + The flake input {option}`from` is rewritten to. + ''; + }; + exact = mkOption { + type = types.bool; + default = true; + description = lib.mdDoc '' + Whether the {option}`from` reference needs to match exactly. If set, + a {option}`from` reference like `nixpkgs` does not + match with a reference like `nixpkgs/nixos-20.03`. + ''; + }; + }; + config = { + from = mkDefault { type = "indirect"; id = name; }; + to = mkIf (config.flake != null) (mkDefault ( + { + type = "path"; + path = config.flake.outPath; + } // filterAttrs + (n: _: n == "lastModified" || n == "rev" || n == "revCount" || n == "narHash") + config.flake + )); + }; + } + )); + default = { }; + description = lib.mdDoc '' + A system-wide flake registry. + ''; + }; + }; + }; + + config = mkIf cfg.enable { + environment.etc."nix/registry.json".text = builtins.toJSON { + version = 2; + flakes = mapAttrsToList (n: v: { inherit (v) from to exact; }) cfg.registry; + }; + }; +} diff --git a/nixos/modules/config/nix-remote-build.nix b/nixos/modules/config/nix-remote-build.nix new file mode 100644 index 000000000000..6bc39f3c7527 --- /dev/null +++ b/nixos/modules/config/nix-remote-build.nix @@ -0,0 +1,230 @@ +/* + Manages the remote build configuration, /etc/nix/machines + + See also + - ./nix.nix + - nixos/modules/services/system/nix-daemon.nix + */ +{ config, lib, ... }: + +let + inherit (lib) + any + concatMapStrings + concatStringsSep + filter + getVersion + mkIf + mkMerge + mkOption + optional + optionalString + types + versionAtLeast + ; + + cfg = config.nix; + + nixPackage = cfg.package.out; + + isNixAtLeast = versionAtLeast (getVersion nixPackage); + + buildMachinesText = + concatMapStrings + (machine: + (concatStringsSep " " ([ + "${optionalString (machine.protocol != null) "${machine.protocol}://"}${optionalString (machine.sshUser != null) "${machine.sshUser}@"}${machine.hostName}" + (if machine.system != null then machine.system else if machine.systems != [ ] then concatStringsSep "," machine.systems else "-") + (if machine.sshKey != null then machine.sshKey else "-") + (toString machine.maxJobs) + (toString machine.speedFactor) + (let res = (machine.supportedFeatures ++ machine.mandatoryFeatures); + in if (res == []) then "-" else (concatStringsSep "," res)) + (let res = machine.mandatoryFeatures; + in if (res == []) then "-" else (concatStringsSep "," machine.mandatoryFeatures)) + ] + ++ optional (isNixAtLeast "2.4pre") (if machine.publicHostKey != null then machine.publicHostKey else "-"))) + + "\n" + ) + cfg.buildMachines; + +in +{ + imports = [ + ./nix.nix + ]; + + options = { + nix = { + buildMachines = mkOption { + type = types.listOf (types.submodule { + options = { + hostName = mkOption { + type = types.str; + example = "nixbuilder.example.org"; + description = lib.mdDoc '' + The hostname of the build machine. + ''; + }; + protocol = mkOption { + type = types.enum [ null "ssh" "ssh-ng" ]; + default = "ssh"; + example = "ssh-ng"; + description = lib.mdDoc '' + The protocol used for communicating with the build machine. + Use `ssh-ng` if your remote builder and your + local Nix version support that improved protocol. + + Use `null` when trying to change the special localhost builder + without a protocol which is for example used by hydra. + ''; + }; + system = mkOption { + type = types.nullOr types.str; + default = null; + example = "x86_64-linux"; + description = lib.mdDoc '' + The system type the build machine can execute derivations on. + Either this attribute or {var}`systems` must be + present, where {var}`system` takes precedence if + both are set. + ''; + }; + systems = mkOption { + type = types.listOf types.str; + default = [ ]; + example = [ "x86_64-linux" "aarch64-linux" ]; + description = lib.mdDoc '' + The system types the build machine can execute derivations on. + Either this attribute or {var}`system` must be + present, where {var}`system` takes precedence if + both are set. + ''; + }; + sshUser = mkOption { + type = types.nullOr types.str; + default = null; + example = "builder"; + description = lib.mdDoc '' + The username to log in as on the remote host. This user must be + able to log in and run nix commands non-interactively. It must + also be privileged to build derivations, so must be included in + {option}`nix.settings.trusted-users`. + ''; + }; + sshKey = mkOption { + type = types.nullOr types.str; + default = null; + example = "/root/.ssh/id_buildhost_builduser"; + description = lib.mdDoc '' + The path to the SSH private key with which to authenticate on + the build machine. The private key must not have a passphrase. + If null, the building user (root on NixOS machines) must have an + appropriate ssh configuration to log in non-interactively. + + Note that for security reasons, this path must point to a file + in the local filesystem, *not* to the nix store. + ''; + }; + maxJobs = mkOption { + type = types.int; + default = 1; + description = lib.mdDoc '' + The number of concurrent jobs the build machine supports. The + build machine will enforce its own limits, but this allows hydra + to schedule better since there is no work-stealing between build + machines. + ''; + }; + speedFactor = mkOption { + type = types.int; + default = 1; + description = lib.mdDoc '' + The relative speed of this builder. This is an arbitrary integer + that indicates the speed of this builder, relative to other + builders. Higher is faster. + ''; + }; + mandatoryFeatures = mkOption { + type = types.listOf types.str; + default = [ ]; + example = [ "big-parallel" ]; + description = lib.mdDoc '' + A list of features mandatory for this builder. The builder will + be ignored for derivations that don't require all features in + this list. All mandatory features are automatically included in + {var}`supportedFeatures`. + ''; + }; + supportedFeatures = mkOption { + type = types.listOf types.str; + default = [ ]; + example = [ "kvm" "big-parallel" ]; + description = lib.mdDoc '' + A list of features supported by this builder. The builder will + be ignored for derivations that require features not in this + list. + ''; + }; + publicHostKey = mkOption { + type = types.nullOr types.str; + default = null; + description = lib.mdDoc '' + The (base64-encoded) public host key of this builder. The field + is calculated via {command}`base64 -w0 /etc/ssh/ssh_host_type_key.pub`. + If null, SSH will use its regular known-hosts file when connecting. + ''; + }; + }; + }); + default = [ ]; + description = lib.mdDoc '' + This option lists the machines to be used if distributed builds are + enabled (see {option}`nix.distributedBuilds`). + Nix will perform derivations on those machines via SSH by copying the + inputs to the Nix store on the remote machine, starting the build, + then copying the output back to the local Nix store. + ''; + }; + + distributedBuilds = mkOption { + type = types.bool; + default = false; + description = lib.mdDoc '' + Whether to distribute builds to the machines listed in + {option}`nix.buildMachines`. + ''; + }; + }; + }; + + # distributedBuilds does *not* inhibit /etc/machines generation; caller may + # override that nix option. + config = mkIf cfg.enable { + assertions = + let badMachine = m: m.system == null && m.systems == [ ]; + in + [ + { + assertion = !(any badMachine cfg.buildMachines); + message = '' + At least one system type (via system or + systems) must be set for every build machine. + Invalid machine specifications: + '' + " " + + (concatStringsSep "\n " + (map (m: m.hostName) + (filter (badMachine) cfg.buildMachines))); + } + ]; + + # List of machines for distributed Nix builds + environment.etc."nix/machines" = + mkIf (cfg.buildMachines != [ ]) { + text = buildMachinesText; + }; + + # Legacy configuration conversion. + nix.settings = mkIf (!cfg.distributedBuilds) { builders = null; }; + }; +} diff --git a/nixos/modules/config/nix.nix b/nixos/modules/config/nix.nix new file mode 100644 index 000000000000..cee4f54db0cb --- /dev/null +++ b/nixos/modules/config/nix.nix @@ -0,0 +1,379 @@ +/* + Manages /etc/nix.conf. + + See also + - ./nix-channel.nix + - ./nix-flakes.nix + - ./nix-remote-build.nix + - nixos/modules/services/system/nix-daemon.nix + */ +{ config, lib, pkgs, ... }: + +let + inherit (lib) + concatStringsSep + boolToString + escape + floatToString + getVersion + isBool + isDerivation + isFloat + isInt + isList + isString + literalExpression + mapAttrsToList + mkAfter + mkDefault + mkIf + mkOption + mkRenamedOptionModuleWith + optionalString + optionals + strings + systems + toPretty + types + versionAtLeast + ; + + cfg = config.nix; + + nixPackage = cfg.package.out; + + isNixAtLeast = versionAtLeast (getVersion nixPackage); + + legacyConfMappings = { + useSandbox = "sandbox"; + buildCores = "cores"; + maxJobs = "max-jobs"; + sandboxPaths = "extra-sandbox-paths"; + binaryCaches = "substituters"; + trustedBinaryCaches = "trusted-substituters"; + binaryCachePublicKeys = "trusted-public-keys"; + autoOptimiseStore = "auto-optimise-store"; + requireSignedBinaryCaches = "require-sigs"; + trustedUsers = "trusted-users"; + allowedUsers = "allowed-users"; + systemFeatures = "system-features"; + }; + + semanticConfType = with types; + let + confAtom = nullOr + (oneOf [ + bool + int + float + str + path + package + ]) // { + description = "Nix config atom (null, bool, int, float, str, path or package)"; + }; + in + attrsOf (either confAtom (listOf confAtom)); + + nixConf = + assert isNixAtLeast "2.2"; + let + + mkValueString = v: + if v == null then "" + else if isInt v then toString v + else if isBool v then boolToString v + else if isFloat v then floatToString v + else if isList v then toString v + else if isDerivation v then toString v + else if builtins.isPath v then toString v + else if isString v then v + else if strings.isConvertibleWithToString v then toString v + else abort "The nix conf value: ${toPretty {} v} can not be encoded"; + + mkKeyValue = k: v: "${escape [ "=" ] k} = ${mkValueString v}"; + + mkKeyValuePairs = attrs: concatStringsSep "\n" (mapAttrsToList mkKeyValue attrs); + + in + pkgs.writeTextFile { + name = "nix.conf"; + text = '' + # WARNING: this file is generated from the nix.* options in + # your NixOS configuration, typically + # /etc/nixos/configuration.nix. Do not edit it! + ${mkKeyValuePairs cfg.settings} + ${cfg.extraOptions} + ''; + checkPhase = lib.optionalString cfg.checkConfig ( + if pkgs.stdenv.hostPlatform != pkgs.stdenv.buildPlatform then '' + echo "Ignoring validation for cross-compilation" + '' + else '' + echo "Validating generated nix.conf" + ln -s $out ./nix.conf + set -e + set +o pipefail + NIX_CONF_DIR=$PWD \ + ${cfg.package}/bin/nix show-config ${optionalString (isNixAtLeast "2.3pre") "--no-net"} \ + ${optionalString (isNixAtLeast "2.4pre") "--option experimental-features nix-command"} \ + |& sed -e 's/^warning:/error:/' \ + | (! grep '${if cfg.checkAllErrors then "^error:" else "^error: unknown setting"}') + set -o pipefail + ''); + }; + +in +{ + imports = [ + (mkRenamedOptionModuleWith { sinceRelease = 2003; from = [ "nix" "useChroot" ]; to = [ "nix" "useSandbox" ]; }) + (mkRenamedOptionModuleWith { sinceRelease = 2003; from = [ "nix" "chrootDirs" ]; to = [ "nix" "sandboxPaths" ]; }) + ] ++ + mapAttrsToList + (oldConf: newConf: + mkRenamedOptionModuleWith { + sinceRelease = 2205; + from = [ "nix" oldConf ]; + to = [ "nix" "settings" newConf ]; + }) + legacyConfMappings; + + options = { + nix = { + checkConfig = mkOption { + type = types.bool; + default = true; + description = lib.mdDoc '' + If enabled, checks that Nix can parse the generated nix.conf. + ''; + }; + + checkAllErrors = mkOption { + type = types.bool; + default = true; + description = lib.mdDoc '' + If enabled, checks the nix.conf parsing for any kind of error. When disabled, checks only for unknown settings. + ''; + }; + + extraOptions = mkOption { + type = types.lines; + default = ""; + example = '' + keep-outputs = true + keep-derivations = true + ''; + description = lib.mdDoc "Additional text appended to {file}`nix.conf`."; + }; + + settings = mkOption { + type = types.submodule { + freeformType = semanticConfType; + + options = { + max-jobs = mkOption { + type = types.either types.int (types.enum [ "auto" ]); + default = "auto"; + example = 64; + description = lib.mdDoc '' + This option defines the maximum number of jobs that Nix will try to + build in parallel. The default is auto, which means it will use all + available logical cores. It is recommend to set it to the total + number of logical cores in your system (e.g., 16 for two CPUs with 4 + cores each and hyper-threading). + ''; + }; + + auto-optimise-store = mkOption { + type = types.bool; + default = false; + example = true; + description = lib.mdDoc '' + If set to true, Nix automatically detects files in the store that have + identical contents, and replaces them with hard links to a single copy. + This saves disk space. If set to false (the default), you can still run + nix-store --optimise to get rid of duplicate files. + ''; + }; + + cores = mkOption { + type = types.int; + default = 0; + example = 64; + description = lib.mdDoc '' + This option defines the maximum number of concurrent tasks during + one build. It affects, e.g., -j option for make. + The special value 0 means that the builder should use all + available CPU cores in the system. Some builds may become + non-deterministic with this option; use with care! Packages will + only be affected if enableParallelBuilding is set for them. + ''; + }; + + sandbox = mkOption { + type = types.either types.bool (types.enum [ "relaxed" ]); + default = true; + description = lib.mdDoc '' + If set, Nix will perform builds in a sandboxed environment that it + will set up automatically for each build. This prevents impurities + in builds by disallowing access to dependencies outside of the Nix + store by using network and mount namespaces in a chroot environment. + + This is enabled by default even though it has a possible performance + impact due to the initial setup time of a sandbox for each build. It + doesn't affect derivation hashes, so changing this option will not + trigger a rebuild of packages. + + When set to "relaxed", this option permits derivations that set + `__noChroot = true;` to run outside of the sandboxed environment. + Exercise caution when using this mode of operation! It is intended to + be a quick hack when building with packages that are not easily setup + to be built reproducibly. + ''; + }; + + extra-sandbox-paths = mkOption { + type = types.listOf types.str; + default = [ ]; + example = [ "/dev" "/proc" ]; + description = lib.mdDoc '' + Directories from the host filesystem to be included + in the sandbox. + ''; + }; + + substituters = mkOption { + type = types.listOf types.str; + description = lib.mdDoc '' + List of binary cache URLs used to obtain pre-built binaries + of Nix packages. + + By default https://cache.nixos.org/ is added. + ''; + }; + + trusted-substituters = mkOption { + type = types.listOf types.str; + default = [ ]; + example = [ "https://hydra.nixos.org/" ]; + description = lib.mdDoc '' + List of binary cache URLs that non-root users can use (in + addition to those specified using + {option}`nix.settings.substituters`) by passing + `--option binary-caches` to Nix commands. + ''; + }; + + require-sigs = mkOption { + type = types.bool; + default = true; + description = lib.mdDoc '' + If enabled (the default), Nix will only download binaries from binary caches if + they are cryptographically signed with any of the keys listed in + {option}`nix.settings.trusted-public-keys`. If disabled, signatures are neither + required nor checked, so it's strongly recommended that you use only + trustworthy caches and https to prevent man-in-the-middle attacks. + ''; + }; + + trusted-public-keys = mkOption { + type = types.listOf types.str; + example = [ "hydra.nixos.org-1:CNHJZBh9K4tP3EKF6FkkgeVYsS3ohTl+oS0Qa8bezVs=" ]; + description = lib.mdDoc '' + List of public keys used to sign binary caches. If + {option}`nix.settings.trusted-public-keys` is enabled, + then Nix will use a binary from a binary cache if and only + if it is signed by *any* of the keys + listed here. By default, only the key for + `cache.nixos.org` is included. + ''; + }; + + trusted-users = mkOption { + type = types.listOf types.str; + default = [ "root" ]; + example = [ "root" "alice" "@wheel" ]; + description = lib.mdDoc '' + A list of names of users that have additional rights when + connecting to the Nix daemon, such as the ability to specify + additional binary caches, or to import unsigned NARs. You + can also specify groups by prefixing them with + `@`; for instance, + `@wheel` means all users in the wheel + group. + ''; + }; + + system-features = mkOption { + type = types.listOf types.str; + example = [ "kvm" "big-parallel" "gccarch-skylake" ]; + description = lib.mdDoc '' + The set of features supported by the machine. Derivations + can express dependencies on system features through the + `requiredSystemFeatures` attribute. + + By default, pseudo-features `nixos-test`, `benchmark`, + and `big-parallel` used in Nixpkgs are set, `kvm` + is also included if it is available. + ''; + }; + + allowed-users = mkOption { + type = types.listOf types.str; + default = [ "*" ]; + example = [ "@wheel" "@builders" "alice" "bob" ]; + description = lib.mdDoc '' + A list of names of users (separated by whitespace) that are + allowed to connect to the Nix daemon. As with + {option}`nix.settings.trusted-users`, you can specify groups by + prefixing them with `@`. Also, you can + allow all users by specifying `*`. The + default is `*`. Note that trusted users are + always allowed to connect. + ''; + }; + }; + }; + default = { }; + example = literalExpression '' + { + use-sandbox = true; + show-trace = true; + + system-features = [ "big-parallel" "kvm" "recursive-nix" ]; + sandbox-paths = { "/bin/sh" = "''${pkgs.busybox-sandbox-shell.out}/bin/busybox"; }; + } + ''; + description = lib.mdDoc '' + Configuration for Nix, see + or + {manpage}`nix.conf(5)` for available options. + The value declared here will be translated directly to the key-value pairs Nix expects. + + You can use {command}`nix-instantiate --eval --strict '' -A config.nix.settings` + to view the current value. By default it is empty. + + Nix configurations defined under {option}`nix.*` will be translated and applied to this + option. In addition, configuration specified in {option}`nix.extraOptions` will be appended + verbatim to the resulting config file. + ''; + }; + }; + }; + + config = mkIf cfg.enable { + environment.etc."nix/nix.conf".source = nixConf; + nix.settings = { + trusted-public-keys = [ "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=" ]; + substituters = mkAfter [ "https://cache.nixos.org/" ]; + system-features = mkDefault ( + [ "nixos-test" "benchmark" "big-parallel" "kvm" ] ++ + optionals (pkgs.stdenv.hostPlatform ? gcc.arch) ( + # a builder can run code for `gcc.arch` and inferior architectures + [ "gccarch-${pkgs.stdenv.hostPlatform.gcc.arch}" ] ++ + map (x: "gccarch-${x}") (systems.architectures.inferiors.${pkgs.stdenv.hostPlatform.gcc.arch} or []) + ) + ); + }; + }; +} diff --git a/nixos/modules/misc/version.nix b/nixos/modules/misc/version.nix index 0f55ab8a09ce..0a66eafe933e 100644 --- a/nixos/modules/misc/version.nix +++ b/nixos/modules/misc/version.nix @@ -140,13 +140,6 @@ in ''; }; - defaultChannel = mkOption { - internal = true; - type = types.str; - default = "https://nixos.org/channels/nixos-unstable"; - description = lib.mdDoc "Default NixOS channel to which the root user is subscribed."; - }; - configurationRevision = mkOption { type = types.nullOr types.str; default = null; diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix index bd715535dd6a..0275d50e83ef 100644 --- a/nixos/modules/module-list.nix +++ b/nixos/modules/module-list.nix @@ -16,6 +16,10 @@ ./config/malloc.nix ./config/mysql.nix ./config/networking.nix + ./config/nix.nix + ./config/nix-channel.nix + ./config/nix-flakes.nix + ./config/nix-remote-build.nix ./config/no-x-libs.nix ./config/nsswitch.nix ./config/power-management.nix @@ -661,7 +665,6 @@ ./services/misc/moonraker.nix ./services/misc/n8n.nix ./services/misc/nitter.nix - ./services/misc/nix-daemon.nix ./services/misc/nix-gc.nix ./services/misc/nix-optimise.nix ./services/misc/nix-ssh-serve.nix @@ -1143,6 +1146,7 @@ ./services/system/earlyoom.nix ./services/system/kerberos/default.nix ./services/system/localtimed.nix + ./services/system/nix-daemon.nix ./services/system/nscd.nix ./services/system/saslauthd.nix ./services/system/self-deploy.nix diff --git a/nixos/modules/services/misc/nix-daemon.nix b/nixos/modules/services/misc/nix-daemon.nix deleted file mode 100644 index 44cf71ad401a..000000000000 --- a/nixos/modules/services/misc/nix-daemon.nix +++ /dev/null @@ -1,844 +0,0 @@ -{ config, lib, pkgs, ... }: - -with lib; - -let - - cfg = config.nix; - - nixPackage = cfg.package.out; - - isNixAtLeast = versionAtLeast (getVersion nixPackage); - - makeNixBuildUser = nr: { - name = "nixbld${toString nr}"; - value = { - description = "Nix build user ${toString nr}"; - - /* - For consistency with the setgid(2), setuid(2), and setgroups(2) - calls in `libstore/build.cc', don't add any supplementary group - here except "nixbld". - */ - uid = builtins.add config.ids.uids.nixbld nr; - isSystemUser = true; - group = "nixbld"; - extraGroups = [ "nixbld" ]; - }; - }; - - nixbldUsers = listToAttrs (map makeNixBuildUser (range 1 cfg.nrBuildUsers)); - - nixConf = - assert isNixAtLeast "2.2"; - let - - mkValueString = v: - if v == null then "" - else if isInt v then toString v - else if isBool v then boolToString v - else if isFloat v then floatToString v - else if isList v then toString v - else if isDerivation v then toString v - else if builtins.isPath v then toString v - else if isString v then v - else if strings.isConvertibleWithToString v then toString v - else abort "The nix conf value: ${toPretty {} v} can not be encoded"; - - mkKeyValue = k: v: "${escape [ "=" ] k} = ${mkValueString v}"; - - mkKeyValuePairs = attrs: concatStringsSep "\n" (mapAttrsToList mkKeyValue attrs); - - in - pkgs.writeTextFile { - name = "nix.conf"; - text = '' - # WARNING: this file is generated from the nix.* options in - # your NixOS configuration, typically - # /etc/nixos/configuration.nix. Do not edit it! - ${mkKeyValuePairs cfg.settings} - ${cfg.extraOptions} - ''; - checkPhase = lib.optionalString cfg.checkConfig ( - if pkgs.stdenv.hostPlatform != pkgs.stdenv.buildPlatform then '' - echo "Ignoring validation for cross-compilation" - '' - else '' - echo "Validating generated nix.conf" - ln -s $out ./nix.conf - set -e - set +o pipefail - NIX_CONF_DIR=$PWD \ - ${cfg.package}/bin/nix show-config ${optionalString (isNixAtLeast "2.3pre") "--no-net"} \ - ${optionalString (isNixAtLeast "2.4pre") "--option experimental-features nix-command"} \ - |& sed -e 's/^warning:/error:/' \ - | (! grep '${if cfg.checkAllErrors then "^error:" else "^error: unknown setting"}') - set -o pipefail - ''); - }; - - legacyConfMappings = { - useSandbox = "sandbox"; - buildCores = "cores"; - maxJobs = "max-jobs"; - sandboxPaths = "extra-sandbox-paths"; - binaryCaches = "substituters"; - trustedBinaryCaches = "trusted-substituters"; - binaryCachePublicKeys = "trusted-public-keys"; - autoOptimiseStore = "auto-optimise-store"; - requireSignedBinaryCaches = "require-sigs"; - trustedUsers = "trusted-users"; - allowedUsers = "allowed-users"; - systemFeatures = "system-features"; - }; - - semanticConfType = with types; - let - confAtom = nullOr - (oneOf [ - bool - int - float - str - path - package - ]) // { - description = "Nix config atom (null, bool, int, float, str, path or package)"; - }; - in - attrsOf (either confAtom (listOf confAtom)); - -in - -{ - imports = [ - (mkRenamedOptionModuleWith { sinceRelease = 2003; from = [ "nix" "useChroot" ]; to = [ "nix" "useSandbox" ]; }) - (mkRenamedOptionModuleWith { sinceRelease = 2003; from = [ "nix" "chrootDirs" ]; to = [ "nix" "sandboxPaths" ]; }) - (mkRenamedOptionModuleWith { sinceRelease = 2205; from = [ "nix" "daemonIONiceLevel" ]; to = [ "nix" "daemonIOSchedPriority" ]; }) - (mkRenamedOptionModuleWith { sinceRelease = 2211; from = [ "nix" "readOnlyStore" ]; to = [ "boot" "readOnlyNixStore" ]; }) - (mkRemovedOptionModule [ "nix" "daemonNiceLevel" ] "Consider nix.daemonCPUSchedPolicy instead.") - ] ++ mapAttrsToList (oldConf: newConf: mkRenamedOptionModuleWith { sinceRelease = 2205; from = [ "nix" oldConf ]; to = [ "nix" "settings" newConf ]; }) legacyConfMappings; - - ###### interface - - options = { - - nix = { - - enable = mkOption { - type = types.bool; - default = true; - description = lib.mdDoc '' - Whether to enable Nix. - Disabling Nix makes the system hard to modify and the Nix programs and configuration will not be made available by NixOS itself. - ''; - }; - - package = mkOption { - type = types.package; - default = pkgs.nix; - defaultText = literalExpression "pkgs.nix"; - description = lib.mdDoc '' - This option specifies the Nix package instance to use throughout the system. - ''; - }; - - distributedBuilds = mkOption { - type = types.bool; - default = false; - description = lib.mdDoc '' - Whether to distribute builds to the machines listed in - {option}`nix.buildMachines`. - ''; - }; - - daemonCPUSchedPolicy = mkOption { - type = types.enum [ "other" "batch" "idle" ]; - default = "other"; - example = "batch"; - description = lib.mdDoc '' - Nix daemon process CPU scheduling policy. This policy propagates to - build processes. `other` is the default scheduling - policy for regular tasks. The `batch` policy is - similar to `other`, but optimised for - non-interactive tasks. `idle` is for extremely - low-priority tasks that should only be run when no other task - requires CPU time. - - Please note that while using the `idle` policy may - greatly improve responsiveness of a system performing expensive - builds, it may also slow down and potentially starve crucial - configuration updates during load. - - `idle` may therefore be a sensible policy for - systems that experience only intermittent phases of high CPU load, - such as desktop or portable computers used interactively. Other - systems should use the `other` or - `batch` policy instead. - - For more fine-grained resource control, please refer to - {manpage}`systemd.resource-control(5)` and adjust - {option}`systemd.services.nix-daemon` directly. - ''; - }; - - daemonIOSchedClass = mkOption { - type = types.enum [ "best-effort" "idle" ]; - default = "best-effort"; - example = "idle"; - description = lib.mdDoc '' - Nix daemon process I/O scheduling class. This class propagates to - build processes. `best-effort` is the default - class for regular tasks. The `idle` class is for - extremely low-priority tasks that should only perform I/O when no - other task does. - - Please note that while using the `idle` scheduling - class can improve responsiveness of a system performing expensive - builds, it might also slow down or starve crucial configuration - updates during load. - - `idle` may therefore be a sensible class for - systems that experience only intermittent phases of high I/O load, - such as desktop or portable computers used interactively. Other - systems should use the `best-effort` class. - ''; - }; - - daemonIOSchedPriority = mkOption { - type = types.int; - default = 4; - example = 1; - description = lib.mdDoc '' - Nix daemon process I/O scheduling priority. This priority propagates - to build processes. The supported priorities depend on the - scheduling policy: With idle, priorities are not used in scheduling - decisions. best-effort supports values in the range 0 (high) to 7 - (low). - ''; - }; - - buildMachines = mkOption { - type = types.listOf (types.submodule { - options = { - hostName = mkOption { - type = types.str; - example = "nixbuilder.example.org"; - description = lib.mdDoc '' - The hostname of the build machine. - ''; - }; - protocol = mkOption { - type = types.enum [ null "ssh" "ssh-ng" ]; - default = "ssh"; - example = "ssh-ng"; - description = lib.mdDoc '' - The protocol used for communicating with the build machine. - Use `ssh-ng` if your remote builder and your - local Nix version support that improved protocol. - - Use `null` when trying to change the special localhost builder - without a protocol which is for example used by hydra. - ''; - }; - system = mkOption { - type = types.nullOr types.str; - default = null; - example = "x86_64-linux"; - description = lib.mdDoc '' - The system type the build machine can execute derivations on. - Either this attribute or {var}`systems` must be - present, where {var}`system` takes precedence if - both are set. - ''; - }; - systems = mkOption { - type = types.listOf types.str; - default = [ ]; - example = [ "x86_64-linux" "aarch64-linux" ]; - description = lib.mdDoc '' - The system types the build machine can execute derivations on. - Either this attribute or {var}`system` must be - present, where {var}`system` takes precedence if - both are set. - ''; - }; - sshUser = mkOption { - type = types.nullOr types.str; - default = null; - example = "builder"; - description = lib.mdDoc '' - The username to log in as on the remote host. This user must be - able to log in and run nix commands non-interactively. It must - also be privileged to build derivations, so must be included in - {option}`nix.settings.trusted-users`. - ''; - }; - sshKey = mkOption { - type = types.nullOr types.str; - default = null; - example = "/root/.ssh/id_buildhost_builduser"; - description = lib.mdDoc '' - The path to the SSH private key with which to authenticate on - the build machine. The private key must not have a passphrase. - If null, the building user (root on NixOS machines) must have an - appropriate ssh configuration to log in non-interactively. - - Note that for security reasons, this path must point to a file - in the local filesystem, *not* to the nix store. - ''; - }; - maxJobs = mkOption { - type = types.int; - default = 1; - description = lib.mdDoc '' - The number of concurrent jobs the build machine supports. The - build machine will enforce its own limits, but this allows hydra - to schedule better since there is no work-stealing between build - machines. - ''; - }; - speedFactor = mkOption { - type = types.int; - default = 1; - description = lib.mdDoc '' - The relative speed of this builder. This is an arbitrary integer - that indicates the speed of this builder, relative to other - builders. Higher is faster. - ''; - }; - mandatoryFeatures = mkOption { - type = types.listOf types.str; - default = [ ]; - example = [ "big-parallel" ]; - description = lib.mdDoc '' - A list of features mandatory for this builder. The builder will - be ignored for derivations that don't require all features in - this list. All mandatory features are automatically included in - {var}`supportedFeatures`. - ''; - }; - supportedFeatures = mkOption { - type = types.listOf types.str; - default = [ ]; - example = [ "kvm" "big-parallel" ]; - description = lib.mdDoc '' - A list of features supported by this builder. The builder will - be ignored for derivations that require features not in this - list. - ''; - }; - publicHostKey = mkOption { - type = types.nullOr types.str; - default = null; - description = lib.mdDoc '' - The (base64-encoded) public host key of this builder. The field - is calculated via {command}`base64 -w0 /etc/ssh/ssh_host_type_key.pub`. - If null, SSH will use its regular known-hosts file when connecting. - ''; - }; - }; - }); - default = [ ]; - description = lib.mdDoc '' - This option lists the machines to be used if distributed builds are - enabled (see {option}`nix.distributedBuilds`). - Nix will perform derivations on those machines via SSH by copying the - inputs to the Nix store on the remote machine, starting the build, - then copying the output back to the local Nix store. - ''; - }; - - # Environment variables for running Nix. - envVars = mkOption { - type = types.attrs; - internal = true; - default = { }; - description = lib.mdDoc "Environment variables used by Nix."; - }; - - nrBuildUsers = mkOption { - type = types.int; - description = lib.mdDoc '' - Number of `nixbld` user accounts created to - perform secure concurrent builds. If you receive an error - message saying that “all build users are currently in use”, - you should increase this value. - ''; - }; - - nixPath = mkOption { - type = types.listOf types.str; - default = [ - "nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixos" - "nixos-config=/etc/nixos/configuration.nix" - "/nix/var/nix/profiles/per-user/root/channels" - ]; - description = lib.mdDoc '' - The default Nix expression search path, used by the Nix - evaluator to look up paths enclosed in angle brackets - (e.g. ``). - ''; - }; - - checkConfig = mkOption { - type = types.bool; - default = true; - description = lib.mdDoc '' - If enabled, checks that Nix can parse the generated nix.conf. - ''; - }; - - checkAllErrors = mkOption { - type = types.bool; - default = true; - description = lib.mdDoc '' - If enabled, checks the nix.conf parsing for any kind of error. When disabled, checks only for unknown settings. - ''; - }; - - registry = mkOption { - type = types.attrsOf (types.submodule ( - let - referenceAttrs = with types; attrsOf (oneOf [ - str - int - bool - path - package - ]); - in - { config, name, ... }: - { - options = { - from = mkOption { - type = referenceAttrs; - example = { type = "indirect"; id = "nixpkgs"; }; - description = lib.mdDoc "The flake reference to be rewritten."; - }; - to = mkOption { - type = referenceAttrs; - example = { type = "github"; owner = "my-org"; repo = "my-nixpkgs"; }; - description = lib.mdDoc "The flake reference {option}`from` is rewritten to."; - }; - flake = mkOption { - type = types.nullOr types.attrs; - default = null; - example = literalExpression "nixpkgs"; - description = lib.mdDoc '' - The flake input {option}`from` is rewritten to. - ''; - }; - exact = mkOption { - type = types.bool; - default = true; - description = lib.mdDoc '' - Whether the {option}`from` reference needs to match exactly. If set, - a {option}`from` reference like `nixpkgs` does not - match with a reference like `nixpkgs/nixos-20.03`. - ''; - }; - }; - config = { - from = mkDefault { type = "indirect"; id = name; }; - to = mkIf (config.flake != null) (mkDefault ( - { - type = "path"; - path = config.flake.outPath; - } // filterAttrs - (n: _: n == "lastModified" || n == "rev" || n == "revCount" || n == "narHash") - config.flake - )); - }; - } - )); - default = { }; - description = lib.mdDoc '' - A system-wide flake registry. - ''; - }; - - extraOptions = mkOption { - type = types.lines; - default = ""; - example = '' - keep-outputs = true - keep-derivations = true - ''; - description = lib.mdDoc "Additional text appended to {file}`nix.conf`."; - }; - - settings = mkOption { - type = types.submodule { - freeformType = semanticConfType; - - options = { - max-jobs = mkOption { - type = types.either types.int (types.enum [ "auto" ]); - default = "auto"; - example = 64; - description = lib.mdDoc '' - This option defines the maximum number of jobs that Nix will try to - build in parallel. The default is auto, which means it will use all - available logical cores. It is recommend to set it to the total - number of logical cores in your system (e.g., 16 for two CPUs with 4 - cores each and hyper-threading). - ''; - }; - - auto-optimise-store = mkOption { - type = types.bool; - default = false; - example = true; - description = lib.mdDoc '' - If set to true, Nix automatically detects files in the store that have - identical contents, and replaces them with hard links to a single copy. - This saves disk space. If set to false (the default), you can still run - nix-store --optimise to get rid of duplicate files. - ''; - }; - - cores = mkOption { - type = types.int; - default = 0; - example = 64; - description = lib.mdDoc '' - This option defines the maximum number of concurrent tasks during - one build. It affects, e.g., -j option for make. - The special value 0 means that the builder should use all - available CPU cores in the system. Some builds may become - non-deterministic with this option; use with care! Packages will - only be affected if enableParallelBuilding is set for them. - ''; - }; - - sandbox = mkOption { - type = types.either types.bool (types.enum [ "relaxed" ]); - default = true; - description = lib.mdDoc '' - If set, Nix will perform builds in a sandboxed environment that it - will set up automatically for each build. This prevents impurities - in builds by disallowing access to dependencies outside of the Nix - store by using network and mount namespaces in a chroot environment. - - This is enabled by default even though it has a possible performance - impact due to the initial setup time of a sandbox for each build. It - doesn't affect derivation hashes, so changing this option will not - trigger a rebuild of packages. - - When set to "relaxed", this option permits derivations that set - `__noChroot = true;` to run outside of the sandboxed environment. - Exercise caution when using this mode of operation! It is intended to - be a quick hack when building with packages that are not easily setup - to be built reproducibly. - ''; - }; - - extra-sandbox-paths = mkOption { - type = types.listOf types.str; - default = [ ]; - example = [ "/dev" "/proc" ]; - description = lib.mdDoc '' - Directories from the host filesystem to be included - in the sandbox. - ''; - }; - - substituters = mkOption { - type = types.listOf types.str; - description = lib.mdDoc '' - List of binary cache URLs used to obtain pre-built binaries - of Nix packages. - - By default https://cache.nixos.org/ is added. - ''; - }; - - trusted-substituters = mkOption { - type = types.listOf types.str; - default = [ ]; - example = [ "https://hydra.nixos.org/" ]; - description = lib.mdDoc '' - List of binary cache URLs that non-root users can use (in - addition to those specified using - {option}`nix.settings.substituters`) by passing - `--option binary-caches` to Nix commands. - ''; - }; - - require-sigs = mkOption { - type = types.bool; - default = true; - description = lib.mdDoc '' - If enabled (the default), Nix will only download binaries from binary caches if - they are cryptographically signed with any of the keys listed in - {option}`nix.settings.trusted-public-keys`. If disabled, signatures are neither - required nor checked, so it's strongly recommended that you use only - trustworthy caches and https to prevent man-in-the-middle attacks. - ''; - }; - - trusted-public-keys = mkOption { - type = types.listOf types.str; - example = [ "hydra.nixos.org-1:CNHJZBh9K4tP3EKF6FkkgeVYsS3ohTl+oS0Qa8bezVs=" ]; - description = lib.mdDoc '' - List of public keys used to sign binary caches. If - {option}`nix.settings.trusted-public-keys` is enabled, - then Nix will use a binary from a binary cache if and only - if it is signed by *any* of the keys - listed here. By default, only the key for - `cache.nixos.org` is included. - ''; - }; - - trusted-users = mkOption { - type = types.listOf types.str; - default = [ "root" ]; - example = [ "root" "alice" "@wheel" ]; - description = lib.mdDoc '' - A list of names of users that have additional rights when - connecting to the Nix daemon, such as the ability to specify - additional binary caches, or to import unsigned NARs. You - can also specify groups by prefixing them with - `@`; for instance, - `@wheel` means all users in the wheel - group. - ''; - }; - - system-features = mkOption { - type = types.listOf types.str; - example = [ "kvm" "big-parallel" "gccarch-skylake" ]; - description = lib.mdDoc '' - The set of features supported by the machine. Derivations - can express dependencies on system features through the - `requiredSystemFeatures` attribute. - - By default, pseudo-features `nixos-test`, `benchmark`, - and `big-parallel` used in Nixpkgs are set, `kvm` - is also included if it is available. - ''; - }; - - allowed-users = mkOption { - type = types.listOf types.str; - default = [ "*" ]; - example = [ "@wheel" "@builders" "alice" "bob" ]; - description = lib.mdDoc '' - A list of names of users (separated by whitespace) that are - allowed to connect to the Nix daemon. As with - {option}`nix.settings.trusted-users`, you can specify groups by - prefixing them with `@`. Also, you can - allow all users by specifying `*`. The - default is `*`. Note that trusted users are - always allowed to connect. - ''; - }; - }; - }; - default = { }; - example = literalExpression '' - { - use-sandbox = true; - show-trace = true; - - system-features = [ "big-parallel" "kvm" "recursive-nix" ]; - sandbox-paths = { "/bin/sh" = "''${pkgs.busybox-sandbox-shell.out}/bin/busybox"; }; - } - ''; - description = lib.mdDoc '' - Configuration for Nix, see - or - {manpage}`nix.conf(5)` for available options. - The value declared here will be translated directly to the key-value pairs Nix expects. - - You can use {command}`nix-instantiate --eval --strict '' -A config.nix.settings` - to view the current value. By default it is empty. - - Nix configurations defined under {option}`nix.*` will be translated and applied to this - option. In addition, configuration specified in {option}`nix.extraOptions` will be appended - verbatim to the resulting config file. - ''; - }; - }; - }; - - - ###### implementation - - config = mkIf cfg.enable { - environment.systemPackages = - [ - nixPackage - pkgs.nix-info - ] - ++ optional (config.programs.bash.enableCompletion) pkgs.nix-bash-completions; - - environment.etc."nix/nix.conf".source = nixConf; - - environment.etc."nix/registry.json".text = builtins.toJSON { - version = 2; - flakes = mapAttrsToList (n: v: { inherit (v) from to exact; }) cfg.registry; - }; - - # List of machines for distributed Nix builds in the format - # expected by build-remote.pl. - environment.etc."nix/machines" = mkIf (cfg.buildMachines != [ ]) { - text = - concatMapStrings - (machine: - (concatStringsSep " " ([ - "${optionalString (machine.protocol != null) "${machine.protocol}://"}${optionalString (machine.sshUser != null) "${machine.sshUser}@"}${machine.hostName}" - (if machine.system != null then machine.system else if machine.systems != [ ] then concatStringsSep "," machine.systems else "-") - (if machine.sshKey != null then machine.sshKey else "-") - (toString machine.maxJobs) - (toString machine.speedFactor) - (let res = (machine.supportedFeatures ++ machine.mandatoryFeatures); - in if (res == []) then "-" else (concatStringsSep "," res)) - (let res = machine.mandatoryFeatures; - in if (res == []) then "-" else (concatStringsSep "," machine.mandatoryFeatures)) - ] - ++ optional (isNixAtLeast "2.4pre") (if machine.publicHostKey != null then machine.publicHostKey else "-"))) - + "\n" - ) - cfg.buildMachines; - }; - - assertions = - let badMachine = m: m.system == null && m.systems == [ ]; - in - [ - { - assertion = !(any badMachine cfg.buildMachines); - message = '' - At least one system type (via system or - systems) must be set for every build machine. - Invalid machine specifications: - '' + " " + - (concatStringsSep "\n " - (map (m: m.hostName) - (filter (badMachine) cfg.buildMachines))); - } - ]; - - systemd.packages = [ nixPackage ]; - - # Will only work once https://github.com/NixOS/nix/pull/6285 is merged - # systemd.tmpfiles.packages = [ nixPackage ]; - - # Can be dropped for Nix > https://github.com/NixOS/nix/pull/6285 - systemd.tmpfiles.rules = [ - "d /nix/var/nix/daemon-socket 0755 root root - -" - ]; - - systemd.sockets.nix-daemon.wantedBy = [ "sockets.target" ]; - - systemd.services.nix-daemon = - { - path = [ nixPackage pkgs.util-linux config.programs.ssh.package ] - ++ optionals cfg.distributedBuilds [ pkgs.gzip ]; - - environment = cfg.envVars - // { CURL_CA_BUNDLE = "/etc/ssl/certs/ca-certificates.crt"; } - // config.networking.proxy.envVars; - - unitConfig.RequiresMountsFor = "/nix/store"; - - serviceConfig = - { - CPUSchedulingPolicy = cfg.daemonCPUSchedPolicy; - IOSchedulingClass = cfg.daemonIOSchedClass; - IOSchedulingPriority = cfg.daemonIOSchedPriority; - LimitNOFILE = 1048576; - }; - - restartTriggers = [ nixConf ]; - - # `stopIfChanged = false` changes to switch behavior - # from stop -> update units -> start - # to update units -> restart - # - # The `stopIfChanged` setting therefore controls a trade-off between a - # more predictable lifecycle, which runs the correct "version" of - # the `ExecStop` line, and on the other hand the availability of - # sockets during the switch, as the effectiveness of the stop operation - # depends on the socket being stopped as well. - # - # As `nix-daemon.service` does not make use of `ExecStop`, we prefer - # to keep the socket up and available. This is important for machines - # that run Nix-based services, such as automated build, test, and deploy - # services, that expect the daemon socket to be available at all times. - # - # Notably, the Nix client does not retry on failure to connect to the - # daemon socket, and the in-process RemoteStore instance will disable - # itself. This makes retries infeasible even for services that are - # aware of the issue. Failure to connect can affect not only new client - # processes, but also new RemoteStore instances in existing processes, - # as well as existing RemoteStore instances that have not saturated - # their connection pool. - # - # Also note that `stopIfChanged = true` does not kill existing - # connection handling daemons, as one might wish to happen before a - # breaking Nix upgrade (which is rare). The daemon forks that handle - # the individual connections split off into their own sessions, causing - # them not to be stopped by systemd. - # If a Nix upgrade does require all existing daemon processes to stop, - # nix-daemon must do so on its own accord, and only when the new version - # starts and detects that Nix's persistent state needs an upgrade. - stopIfChanged = false; - - }; - - # Set up the environment variables for running Nix. - environment.sessionVariables = cfg.envVars // { NIX_PATH = cfg.nixPath; }; - - environment.extraInit = - '' - if [ -e "$HOME/.nix-defexpr/channels" ]; then - export NIX_PATH="$HOME/.nix-defexpr/channels''${NIX_PATH:+:$NIX_PATH}" - fi - ''; - - nix.nrBuildUsers = mkDefault ( - if cfg.settings.auto-allocate-uids or false then 0 - else max 32 (if cfg.settings.max-jobs == "auto" then 0 else cfg.settings.max-jobs) - ); - - users.users = nixbldUsers; - - services.xserver.displayManager.hiddenUsers = attrNames nixbldUsers; - - system.activationScripts.nix = stringAfter [ "etc" "users" ] - '' - install -m 0755 -d /nix/var/nix/{gcroots,profiles}/per-user - - # Subscribe the root user to the NixOS channel by default. - if [ ! -e "/root/.nix-channels" ]; then - echo "${config.system.defaultChannel} nixos" > "/root/.nix-channels" - fi - ''; - - # Legacy configuration conversion. - nix.settings = mkMerge [ - { - trusted-public-keys = [ "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=" ]; - substituters = mkAfter [ "https://cache.nixos.org/" ]; - - system-features = mkDefault ( - [ "nixos-test" "benchmark" "big-parallel" "kvm" ] ++ - optionals (pkgs.stdenv.hostPlatform ? gcc.arch) ( - # a builder can run code for `gcc.arch` and inferior architectures - [ "gccarch-${pkgs.stdenv.hostPlatform.gcc.arch}" ] ++ - map (x: "gccarch-${x}") (systems.architectures.inferiors.${pkgs.stdenv.hostPlatform.gcc.arch} or []) - ) - ); - } - - (mkIf (!cfg.distributedBuilds) { builders = null; }) - - (mkIf (isNixAtLeast "2.3pre") { sandbox-fallback = false; }) - ]; - - }; - -} diff --git a/nixos/modules/services/system/nix-daemon.nix b/nixos/modules/services/system/nix-daemon.nix new file mode 100644 index 000000000000..7e7ebd7adf84 --- /dev/null +++ b/nixos/modules/services/system/nix-daemon.nix @@ -0,0 +1,263 @@ +/* + Declares what makes the nix-daemon work on systemd. + + See also + - nixos/modules/config/nix.nix: the nix.conf + - nixos/modules/config/nix-remote-build.nix: the nix.conf +*/ +{ config, lib, pkgs, ... }: + +with lib; + +let + + cfg = config.nix; + + nixPackage = cfg.package.out; + + isNixAtLeast = versionAtLeast (getVersion nixPackage); + + makeNixBuildUser = nr: { + name = "nixbld${toString nr}"; + value = { + description = "Nix build user ${toString nr}"; + + /* + For consistency with the setgid(2), setuid(2), and setgroups(2) + calls in `libstore/build.cc', don't add any supplementary group + here except "nixbld". + */ + uid = builtins.add config.ids.uids.nixbld nr; + isSystemUser = true; + group = "nixbld"; + extraGroups = [ "nixbld" ]; + }; + }; + + nixbldUsers = listToAttrs (map makeNixBuildUser (range 1 cfg.nrBuildUsers)); + +in + +{ + imports = [ + ../../config/nix.nix + + (mkRenamedOptionModuleWith { sinceRelease = 2205; from = [ "nix" "daemonIONiceLevel" ]; to = [ "nix" "daemonIOSchedPriority" ]; }) + (mkRenamedOptionModuleWith { sinceRelease = 2211; from = [ "nix" "readOnlyStore" ]; to = [ "boot" "readOnlyNixStore" ]; }) + (mkRemovedOptionModule [ "nix" "daemonNiceLevel" ] "Consider nix.daemonCPUSchedPolicy instead.") + ]; + + ###### interface + + options = { + + nix = { + + enable = mkOption { + type = types.bool; + default = true; + description = lib.mdDoc '' + Whether to enable Nix. + Disabling Nix makes the system hard to modify and the Nix programs and configuration will not be made available by NixOS itself. + ''; + }; + + package = mkOption { + type = types.package; + default = pkgs.nix; + defaultText = literalExpression "pkgs.nix"; + description = lib.mdDoc '' + This option specifies the Nix package instance to use throughout the system. + ''; + }; + + daemonCPUSchedPolicy = mkOption { + type = types.enum [ "other" "batch" "idle" ]; + default = "other"; + example = "batch"; + description = lib.mdDoc '' + Nix daemon process CPU scheduling policy. This policy propagates to + build processes. `other` is the default scheduling + policy for regular tasks. The `batch` policy is + similar to `other`, but optimised for + non-interactive tasks. `idle` is for extremely + low-priority tasks that should only be run when no other task + requires CPU time. + + Please note that while using the `idle` policy may + greatly improve responsiveness of a system performing expensive + builds, it may also slow down and potentially starve crucial + configuration updates during load. + + `idle` may therefore be a sensible policy for + systems that experience only intermittent phases of high CPU load, + such as desktop or portable computers used interactively. Other + systems should use the `other` or + `batch` policy instead. + + For more fine-grained resource control, please refer to + {manpage}`systemd.resource-control(5)` and adjust + {option}`systemd.services.nix-daemon` directly. + ''; + }; + + daemonIOSchedClass = mkOption { + type = types.enum [ "best-effort" "idle" ]; + default = "best-effort"; + example = "idle"; + description = lib.mdDoc '' + Nix daemon process I/O scheduling class. This class propagates to + build processes. `best-effort` is the default + class for regular tasks. The `idle` class is for + extremely low-priority tasks that should only perform I/O when no + other task does. + + Please note that while using the `idle` scheduling + class can improve responsiveness of a system performing expensive + builds, it might also slow down or starve crucial configuration + updates during load. + + `idle` may therefore be a sensible class for + systems that experience only intermittent phases of high I/O load, + such as desktop or portable computers used interactively. Other + systems should use the `best-effort` class. + ''; + }; + + daemonIOSchedPriority = mkOption { + type = types.int; + default = 4; + example = 1; + description = lib.mdDoc '' + Nix daemon process I/O scheduling priority. This priority propagates + to build processes. The supported priorities depend on the + scheduling policy: With idle, priorities are not used in scheduling + decisions. best-effort supports values in the range 0 (high) to 7 + (low). + ''; + }; + + # Environment variables for running Nix. + envVars = mkOption { + type = types.attrs; + internal = true; + default = { }; + description = lib.mdDoc "Environment variables used by Nix."; + }; + + nrBuildUsers = mkOption { + type = types.int; + description = lib.mdDoc '' + Number of `nixbld` user accounts created to + perform secure concurrent builds. If you receive an error + message saying that “all build users are currently in use”, + you should increase this value. + ''; + }; + }; + }; + + + ###### implementation + + config = mkIf cfg.enable { + environment.systemPackages = + [ + nixPackage + pkgs.nix-info + ] + ++ optional (config.programs.bash.enableCompletion) pkgs.nix-bash-completions; + + systemd.packages = [ nixPackage ]; + + # Will only work once https://github.com/NixOS/nix/pull/6285 is merged + # systemd.tmpfiles.packages = [ nixPackage ]; + + # Can be dropped for Nix > https://github.com/NixOS/nix/pull/6285 + systemd.tmpfiles.rules = [ + "d /nix/var/nix/daemon-socket 0755 root root - -" + ]; + + systemd.sockets.nix-daemon.wantedBy = [ "sockets.target" ]; + + systemd.services.nix-daemon = + { + path = [ nixPackage pkgs.util-linux config.programs.ssh.package ] + ++ optionals cfg.distributedBuilds [ pkgs.gzip ]; + + environment = cfg.envVars + // { CURL_CA_BUNDLE = "/etc/ssl/certs/ca-certificates.crt"; } + // config.networking.proxy.envVars; + + unitConfig.RequiresMountsFor = "/nix/store"; + + serviceConfig = + { + CPUSchedulingPolicy = cfg.daemonCPUSchedPolicy; + IOSchedulingClass = cfg.daemonIOSchedClass; + IOSchedulingPriority = cfg.daemonIOSchedPriority; + LimitNOFILE = 1048576; + }; + + restartTriggers = [ config.environment.etc."nix/nix.conf".source ]; + + # `stopIfChanged = false` changes to switch behavior + # from stop -> update units -> start + # to update units -> restart + # + # The `stopIfChanged` setting therefore controls a trade-off between a + # more predictable lifecycle, which runs the correct "version" of + # the `ExecStop` line, and on the other hand the availability of + # sockets during the switch, as the effectiveness of the stop operation + # depends on the socket being stopped as well. + # + # As `nix-daemon.service` does not make use of `ExecStop`, we prefer + # to keep the socket up and available. This is important for machines + # that run Nix-based services, such as automated build, test, and deploy + # services, that expect the daemon socket to be available at all times. + # + # Notably, the Nix client does not retry on failure to connect to the + # daemon socket, and the in-process RemoteStore instance will disable + # itself. This makes retries infeasible even for services that are + # aware of the issue. Failure to connect can affect not only new client + # processes, but also new RemoteStore instances in existing processes, + # as well as existing RemoteStore instances that have not saturated + # their connection pool. + # + # Also note that `stopIfChanged = true` does not kill existing + # connection handling daemons, as one might wish to happen before a + # breaking Nix upgrade (which is rare). The daemon forks that handle + # the individual connections split off into their own sessions, causing + # them not to be stopped by systemd. + # If a Nix upgrade does require all existing daemon processes to stop, + # nix-daemon must do so on its own accord, and only when the new version + # starts and detects that Nix's persistent state needs an upgrade. + stopIfChanged = false; + + }; + + # Set up the environment variables for running Nix. + environment.sessionVariables = cfg.envVars; + + nix.nrBuildUsers = mkDefault ( + if cfg.settings.auto-allocate-uids or false then 0 + else max 32 (if cfg.settings.max-jobs == "auto" then 0 else cfg.settings.max-jobs) + ); + + users.users = nixbldUsers; + + services.xserver.displayManager.hiddenUsers = attrNames nixbldUsers; + + system.activationScripts.nix = stringAfter [ "etc" "users" ] + '' + install -m 0755 -d /nix/var/nix/{gcroots,profiles}/per-user + ''; + + # Legacy configuration conversion. + nix.settings = mkMerge [ + (mkIf (isNixAtLeast "2.3pre") { sandbox-fallback = false; }) + ]; + + }; + +}