diff options
Diffstat (limited to 'nixos/modules/profiles/macos-builder.nix')
-rw-r--r-- | nixos/modules/profiles/macos-builder.nix | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/nixos/modules/profiles/macos-builder.nix b/nixos/modules/profiles/macos-builder.nix new file mode 100644 index 000000000000..895dd04cb485 --- /dev/null +++ b/nixos/modules/profiles/macos-builder.nix @@ -0,0 +1,134 @@ +{ config, pkgs, ... }: + +let + keysDirectory = "/var/keys"; + + user = "builder"; + + keyType = "ed25519"; + +in + +{ imports = [ + ../virtualisation/qemu-vm.nix + ]; + + # The builder is not intended to be used interactively + documentation.enable = false; + + environment.etc = { + "ssh/ssh_host_ed25519_key" = { + mode = "0600"; + + source = ./keys/ssh_host_ed25519_key; + }; + + "ssh/ssh_host_ed25519_key.pub" = { + mode = "0644"; + + source = ./keys/ssh_host_ed25519_key.pub; + }; + }; + + # DNS fails for QEMU user networking (SLiRP) on macOS. See: + # + # https://github.com/utmapp/UTM/issues/2353 + # + # This works around that by using a public DNS server other than the DNS + # server that QEMU provides (normally 10.0.2.3) + networking.nameservers = [ "8.8.8.8" ]; + + nix.settings = { + auto-optimise-store = true; + + min-free = 1024 * 1024 * 1024; + + max-free = 3 * 1024 * 1024 * 1024; + + trusted-users = [ "root" user ]; + }; + + services.openssh = { + enable = true; + + authorizedKeysFiles = [ "${keysDirectory}/%u_${keyType}.pub" ]; + }; + + system.build.macos-builder-installer = + let + privateKey = "/etc/nix/${user}_${keyType}"; + + publicKey = "${privateKey}.pub"; + + # This installCredentials script is written so that it's as easy as + # possible for a user to audit before confirming the `sudo` + installCredentials = pkgs.writeShellScript "install-credentials" '' + KEYS="''${1}" + INSTALL=${hostPkgs.coreutils}/bin/install + "''${INSTALL}" -g nixbld -m 600 "''${KEYS}/${user}_${keyType}" ${privateKey} + "''${INSTALL}" -g nixbld -m 644 "''${KEYS}/${user}_${keyType}.pub" ${publicKey} + ''; + + hostPkgs = config.virtualisation.host.pkgs; + + in + hostPkgs.writeShellScriptBin "create-builder" '' + KEYS="''${KEYS:-./keys}" + ${hostPkgs.coreutils}/bin/mkdir --parent "''${KEYS}" + PRIVATE_KEY="''${KEYS}/${user}_${keyType}" + PUBLIC_KEY="''${PRIVATE_KEY}.pub" + if [ ! -e "''${PRIVATE_KEY}" ] || [ ! -e "''${PUBLIC_KEY}" ]; then + ${hostPkgs.coreutils}/bin/rm --force -- "''${PRIVATE_KEY}" "''${PUBLIC_KEY}" + ${hostPkgs.openssh}/bin/ssh-keygen -q -f "''${PRIVATE_KEY}" -t ${keyType} -N "" -C 'builder@localhost' + fi + if ! ${hostPkgs.diffutils}/bin/cmp "''${PUBLIC_KEY}" ${publicKey}; then + (set -x; sudo --reset-timestamp ${installCredentials} "''${KEYS}") + fi + KEYS="$(nix-store --add "$KEYS")" ${config.system.build.vm}/bin/run-nixos-vm + ''; + + system.stateVersion = "22.05"; + + users.users."${user}"= { + isNormalUser = true; + }; + + virtualisation = { + diskSize = 20 * 1024; + + memorySize = 3 * 1024; + + forwardPorts = [ + { from = "host"; guest.port = 22; host.port = 22; } + ]; + + # Disable graphics for the builder since users will likely want to run it + # non-interactively in the background. + graphics = false; + + sharedDirectories.keys = { + source = "\"$KEYS\""; + target = keysDirectory; + }; + + # If we don't enable this option then the host will fail to delegate builds + # to the guest, because: + # + # - The host will lock the path to build + # - The host will delegate the build to the guest + # - The guest will attempt to lock the same path and fail because + # the lockfile on the host is visible on the guest + # + # Snapshotting the host's /nix/store as an image isolates the guest VM's + # /nix/store from the host's /nix/store, preventing this problem. + useNixStoreImage = true; + + # Obviously the /nix/store needs to be writable on the guest in order for it + # to perform builds. + writableStore = true; + + # This ensures that anything built on the guest isn't lost when the guest is + # restarted. + writableStoreUseTmpfs = false; + }; +} |