From 8bba28260af21c1703cdf8aa0d19c8498a78fb81 Mon Sep 17 00:00:00 2001 From: Edward Amsden Date: Wed, 27 Mar 2019 20:52:28 -0400 Subject: [PATCH] nixos/digital-ocean-image: init --- .../virtualisation/digital-ocean-config.nix | 197 ++++++++++++++++++ .../virtualisation/digital-ocean-image.nix | 69 ++++++ .../virtualisation/digital-ocean-init.nix | 95 +++++++++ 3 files changed, 361 insertions(+) create mode 100644 nixos/modules/virtualisation/digital-ocean-config.nix create mode 100644 nixos/modules/virtualisation/digital-ocean-image.nix create mode 100644 nixos/modules/virtualisation/digital-ocean-init.nix diff --git a/nixos/modules/virtualisation/digital-ocean-config.nix b/nixos/modules/virtualisation/digital-ocean-config.nix new file mode 100644 index 000000000000..88cb0cd450e8 --- /dev/null +++ b/nixos/modules/virtualisation/digital-ocean-config.nix @@ -0,0 +1,197 @@ +{ config, pkgs, lib, modulesPath, ... }: +with lib; +{ + imports = [ + (modulesPath + "/profiles/qemu-guest.nix") + (modulesPath + "/virtualisation/digital-ocean-init.nix") + ]; + options.virtualisation.digitalOcean = with types; { + setRootPassword = mkOption { + type = bool; + default = false; + example = true; + description = "Whether to set the root password from the Digital Ocean metadata"; + }; + setSshKeys = mkOption { + type = bool; + default = true; + example = true; + description = "Whether to fetch ssh keys from Digital Ocean"; + }; + seedEntropy = mkOption { + type = bool; + default = true; + example = true; + description = "Whether to run the kernel RNG entropy seeding script from the Digital Ocean vendor data"; + }; + }; + config = + let + cfg = config.virtualisation.digitalOcean; + hostName = config.networking.hostName; + doMetadataFile = "/run/do-metadata/v1.json"; + in mkMerge [{ + fileSystems."/" = { + device = "/dev/disk/by-label/nixos"; + autoResize = true; + fsType = "ext4"; + }; + boot = { + growPartition = true; + kernelParams = [ "console=ttyS0" "panic=1" "boot.panic_on_fail" ]; + initrd.kernelModules = [ "virtio_scsi" ]; + kernelModules = [ "virtio_pci" "virtio_net" ]; + loader = { + grub.device = "/dev/vda"; + timeout = 0; + grub.configurationLimit = 0; + }; + }; + services.openssh = { + enable = mkDefault true; + passwordAuthentication = mkDefault false; + }; + services.do-agent.enable = mkDefault true; + networking = { + hostName = mkDefault ""; # use Digital Ocean metadata server + }; + + /* Check for and wait for the metadata server to become reachable. + * This serves as a dependency for all the other metadata services. */ + systemd.services.digitalocean-metadata = { + path = [ pkgs.curl ]; + description = "Get host metadata provided by Digitalocean"; + script = '' + set -eu + DO_DELAY_ATTEMPTS=0 + while ! curl -fsSL -o $RUNTIME_DIRECTORY/v1.json http://169.254.169.254/metadata/v1.json; do + DO_DELAY_ATTEMPTS=$((DO_DELAY_ATTEMPTS + 1)) + if (( $DO_DELAY_ATTEMPTS >= $DO_DELAY_ATTEMPTS_MAX )); then + echo "giving up" + exit 1 + fi + + echo "metadata unavailable, trying again in 1s..." + sleep 1 + done + chmod 600 $RUNTIME_DIRECTORY/v1.json + ''; + environment = { + DO_DELAY_ATTEMPTS_MAX = "10"; + }; + serviceConfig = { + Type = "oneshot"; + RemainAfterExit = true; + RuntimeDirectory = "do-metadata"; + RuntimeDirectoryPreserve = "yes"; + }; + unitConfig = { + ConditionPathExists = "!${doMetadataFile}"; + After = [ "network-pre.target" ] ++ + optional config.networking.dhcpcd.enable "dhcpcd.service" ++ + optional config.systemd.network.enable "systemd-networkd.service"; + }; + }; + + /* Fetch the root password from the digital ocean metadata. + * There is no specific route for this, so we use jq to get + * it from the One Big JSON metadata blob */ + systemd.services.digitalocean-set-root-password = mkIf cfg.setRootPassword { + path = [ pkgs.shadow pkgs.jq ]; + description = "Set root password provided by Digitalocean"; + wantedBy = [ "multi-user.target" ]; + script = '' + set -eo pipefail + ROOT_PASSWORD=$(jq -er '.auth_key' ${doMetadataFile}) + echo "root:$ROOT_PASSWORD" | chpasswd + mkdir -p /etc/do-metadata/set-root-password + ''; + unitConfig = { + ConditionPathExists = "!/etc/do-metadata/set-root-password"; + Before = optional config.services.openssh.enable "sshd.service"; + After = [ "digitalocean-metadata.service" ]; + Requires = [ "digitalocean-metadata.service" ]; + }; + serviceConfig = { + Type = "oneshot"; + }; + }; + + /* Set the hostname from Digital Ocean, unless the user configured it in + * the NixOS configuration. The cached metadata file isn't used here + * because the hostname is a mutable part of the droplet. */ + systemd.services.digitalocean-set-hostname = mkIf (hostName == "") { + path = [ pkgs.curl pkgs.nettools ]; + description = "Set hostname provided by Digitalocean"; + wantedBy = [ "network.target" ]; + script = '' + set -e + DIGITALOCEAN_HOSTNAME=$(curl -fsSL http://169.254.169.254/metadata/v1/hostname) + hostname "$DIGITALOCEAN_HOSTNAME" + if [[ ! -e /etc/hostname || -w /etc/hostname ]]; then + printf "%s\n" "$DIGITALOCEAN_HOSTNAME" > /etc/hostname + fi + ''; + unitConfig = { + Before = [ "network.target" ]; + After = [ "digitalocean-metadata.service" ]; + Wants = [ "digitalocean-metadata.service" ]; + }; + serviceConfig = { + Type = "oneshot"; + }; + }; + + /* Fetch the ssh keys for root from Digital Ocean */ + systemd.services.digitalocean-ssh-keys = mkIf cfg.setSshKeys { + description = "Set root ssh keys provided by Digital Ocean"; + wantedBy = [ "multi-user.target" ]; + path = [ pkgs.jq ]; + script = '' + set -e + mkdir -m 0700 -p /root/.ssh + jq -er '.public_keys[]' ${doMetadataFile} > /root/.ssh/authorized_keys + chmod 600 /root/.ssh/authorized_keys + ''; + serviceConfig = { + Type = "oneshot"; + RemainAfterExit = true; + }; + unitConfig = { + ConditionPathExists = "!/root/.ssh/authorized_keys"; + Before = optional config.services.openssh.enable "sshd.service"; + After = [ "digitalocean-metadata.service" ]; + Requires = [ "digitalocean-metadata.service" ]; + }; + }; + + /* Initialize the RNG by running the entropy-seed script from the + * Digital Ocean metadata + */ + systemd.services.digitalocean-entropy-seed = mkIf cfg.seedEntropy { + description = "Run the kernel RNG entropy seeding script from the Digital Ocean vendor data"; + wantedBy = [ "network.target" ]; + path = [ pkgs.jq pkgs.mpack ]; + script = '' + set -eo pipefail + TEMPDIR=$(mktemp -d) + jq -er '.vendor_data' ${doMetadataFile} | munpack -tC $TEMPDIR + ENTROPY_SEED=$(grep -rl "DigitalOcean Entropy Seed script" $TEMPDIR) + ${pkgs.runtimeShell} $ENTROPY_SEED + rm -rf $TEMPDIR + ''; + unitConfig = { + Before = [ "network.target" ]; + After = [ "digitalocean-metadata.service" ]; + Requires = [ "digitalocean-metadata.service" ]; + }; + serviceConfig = { + Type = "oneshot"; + }; + }; + + } + ]; + meta.maintainers = with maintainers; [ arianvp eamsden ]; +} + diff --git a/nixos/modules/virtualisation/digital-ocean-image.nix b/nixos/modules/virtualisation/digital-ocean-image.nix new file mode 100644 index 000000000000..b582e235d435 --- /dev/null +++ b/nixos/modules/virtualisation/digital-ocean-image.nix @@ -0,0 +1,69 @@ +{ config, lib, pkgs, ... }: + +with lib; +let + cfg = config.virtualisation.digitalOceanImage; +in +{ + + imports = [ ./digital-ocean-config.nix ]; + + options = { + virtualisation.digitalOceanImage.diskSize = mkOption { + type = with types; int; + default = 4096; + description = '' + Size of disk image. Unit is MB. + ''; + }; + + virtualisation.digitalOceanImage.configFile = mkOption { + type = with types; nullOr path; + default = null; + description = '' + A path to a configuration file which will be placed at + /etc/nixos/configuration.nix and be used when switching + to a new configuration. If set to null, a default + configuration is used that imports + (modulesPath + "/virtualisation/digital-ocean-config.nix"). + ''; + }; + + virtualisation.digitalOceanImage.compressionMethod = mkOption { + type = types.enum [ "gzip" "bzip2" ]; + default = "gzip"; + example = "bzip2"; + description = '' + Disk image compression method. Choose bzip2 to generate smaller images that + take longer to generate but will consume less metered storage space on your + Digital Ocean account. + ''; + }; + }; + + #### implementation + config = { + + system.build.digitalOceanImage = import ../../lib/make-disk-image.nix { + name = "digital-ocean-image"; + format = "qcow2"; + postVM = let + compress = { + "gzip" = "${pkgs.gzip}/bin/gzip"; + "bzip2" = "${pkgs.bzip2}/bin/bzip2"; + }.${cfg.compressionMethod}; + in '' + ${compress} $diskImage + ''; + configFile = if cfg.configFile == null + then config.virtualisation.digitalOcean.defaultConfigFile + else cfg.configFile; + inherit (cfg) diskSize; + inherit config lib pkgs; + }; + + }; + + meta.maintainers = with maintainers; [ arianvp eamsden ]; + +} diff --git a/nixos/modules/virtualisation/digital-ocean-init.nix b/nixos/modules/virtualisation/digital-ocean-init.nix new file mode 100644 index 000000000000..02f4de009fa8 --- /dev/null +++ b/nixos/modules/virtualisation/digital-ocean-init.nix @@ -0,0 +1,95 @@ +{ config, pkgs, lib, ... }: +with lib; +let + cfg = config.virtualisation.digitalOcean; + defaultConfigFile = pkgs.writeText "digitalocean-configuration.nix" '' + { modulesPath, lib, ... }: + { + imports = lib.optional (builtins.pathExists ./do-userdata.nix) ./do-userdata.nix ++ [ + (modulesPath + "/virtualisation/digital-ocean-config.nix") + ]; + } + ''; +in { + options.virtualisation.digitalOcean.rebuildFromUserData = mkOption { + type = types.bool; + default = true; + example = true; + description = "Whether to reconfigure the system from Digital Ocean user data"; + }; + options.virtualisation.digitalOcean.defaultConfigFile = mkOption { + type = types.path; + default = defaultConfigFile; + defaultText = '' + The default configuration imports user-data if applicable and + (modulesPath + "/virtualisation/digital-ocean-config.nix"). + ''; + description = '' + A path to a configuration file which will be placed at + /etc/nixos/configuration.nix and be used when switching to + a new configuration. + ''; + }; + + config = { + systemd.services.digitalocean-init = mkIf cfg.rebuildFromUserData { + description = "Reconfigure the system from Digital Ocean userdata on startup"; + wantedBy = [ "network-online.target" ]; + unitConfig = { + ConditionPathExists = "!/etc/nixos/do-userdata.nix"; + After = [ "digitalocean-metadata.service" "network-online.target" ]; + Requires = [ "digitalocean-metadata.service" ]; + X-StopOnRemoval = false; + }; + serviceConfig = { + Type = "oneshot"; + RemainAfterExit = true; + }; + restartIfChanged = false; + path = [ pkgs.jq pkgs.gnused pkgs.gnugrep pkgs.systemd config.nix.package config.system.build.nixos-rebuild ]; + environment = { + HOME = "/root"; + NIX_PATH = concatStringsSep ":" [ + "/nix/var/nix/profiles/per-user/root/channels/nixos" + "nixos-config=/etc/nixos/configuration.nix" + "/nix/var/nix/profiles/per-user/root/channels" + ]; + }; + script = '' + set -e + echo "attempting to fetch configuration from Digital Ocean user data..." + userData=$(mktemp) + if jq -er '.user_data' /run/do-metadata/v1.json > $userData; then + # If the user-data looks like it could be a nix expression, + # copy it over. Also, look for a magic three-hash comment and set + # that as the channel. + if nix-instantiate --parse $userData > /dev/null; then + channels="$(grep '^###' "$userData" | sed 's|###\s*||')" + printf "%s" "$channels" | while read channel; do + echo "writing channel: $channel" + done + + if [[ -n "$channels" ]]; then + printf "%s" "$channels" > /root/.nix-channels + nix-channel --update + fi + + echo "setting configuration from Digital Ocean user data" + cp "$userData" /etc/nixos/do-userdata.nix + if [[ ! -e /etc/nixos/configuration.nix ]]; then + install -m0644 ${cfg.defaultConfigFile} /etc/nixos/configuration.nix + fi + else + echo "user data does not appear to be a Nix expression; ignoring" + exit + fi + + nixos-rebuild switch + else + echo "no user data is available" + fi + ''; + }; + }; + meta.maintainers = with maintainers; [ arianvp eamsden ]; +}