#!/usr/bin/env bash # Adepted from : # * https://mazzo.li/posts/hetzner-zfs.html # * https://nixos.wiki/wiki/Install_NixOS_on_Hetzner_Online # Installs NixOS on a Hetzner server, wiping the server. # # This is for a specific server configuration; adjust where needed. # # Prerequisites: # * Update the script wherever FIXME is present # # Usage: # ssh root@YOUR_SERVERS_IP bash -s < hetzner-dedicated-wipe-and-install-nixos.sh # # When the script is done, make sure to boot the server from HD, not rescue mode again. # Explanations: # # * Adapted from https://gist.github.com/nh2/78d1c65e33806e7728622dbe748c2b6a # * Following largely https://nixos.org/nixos/manual/index.html#sec-installing-from-other-distro. # * **Important:** We boot in legacy-BIOS mode, not UEFI, because that's what Hetzner uses. # * NVMe devices aren't supported for booting (those require EFI boot) # * We set a custom `configuration.nix` so that we can connect to the machine afterwards, # inspired by https://nixos.wiki/wiki/Install_NixOS_on_Hetzner_Online # * This server has 2 HDDs. # We encrypt all hard drives and put an LVM on it the main logical volume is mirrored # Storage scheme: `partitions -> dm-crypt -> LVM -> ext4`. # # ┌────────┐ ┌────────┐ # │ sda1 │ ◄──── grub ─────► │ sdb1 │ # ├────────┤ ├────────┤ # │ sda2 │ ◄──── /boot ─────► │ sdb2 │ # ├────────┤ ├────────┤ # │ sda3 ├───┐ ┌───┤ sdb3 │ # └────────┘ │ │ └────────┘ # │ │ # ┌────────────▼┐ ┌▼────────────┐ # │ a_encrypted │ │ b_encrypted │ # └────────┬────┘ └────┬────────┘ # │ ┌──────────┐ │ # └─────► LVM vg ◄─────┘ # └────┬─────┘ # │ # ┌─────────────▼──────────────┐ # │ root (mirrored/raid1) │ # ├────────────────────────────┤ # │ nextcloud (mirrored/raid1) │ # ├────────────────────────────┤ # │ media (raid0) │ # └────────────────────────────┘ # * A root user with empty password is created, so that you can just login # as root and press enter when using the Hetzner spider KVM. # Of course that empty-password login isn't exposed to the Internet. # Change the password afterwards to avoid anyone with physical access # being able to login without any authentication. # * The script reboots at the end. # * does not use uefi (check if you can : efibootmgr) # # FIXME : change password MAIN_PASSWORD="YOLO" set -eu set -o pipefail set -x # Inspect existing disks lsblk # Cleanup # ------- # Undo existing setups to allow running the script multiple times to iterate on it. # We allow these operations to fail for the case the script runs the first time. set +e umount /mnt/boot-{1,2} umount /mnt vgchange -an cryptsetup close a_encrypted cryptsetup close b_encrypted set -e # Stop all mdadm arrays that the boot may have activated. mdadm --stop --scan # Create partition tables (--script to not ask) # --------------------------------------------- format() { parted --script "$1" -- mklabel gpt parted --script "$1" -- mkpart 'BIOS-boot-partition' 1MB 2MB set 1 bios_grub on #parted --script "$1" -- mkpart 'boot' 2MB 512MiB #parted --script "$1" -- mkpart ESP fat32 2MB 512MiB parted --script "$1" -- mkpart 'boot' fat32 2MB 512MiB set 2 boot on parted --script "$1" -- mkpart primary 512MiB 100% parted --script "$1" -- print } # In this particular machine we have two NVMe disks format /dev/sda format /dev/sdb # Relaod partitions partprobe # Wait for all devices to exist udevadm settle --timeout=5 --exit-if-exists=/dev/sda1 udevadm settle --timeout=5 --exit-if-exists=/dev/sda2 udevadm settle --timeout=5 --exit-if-exists=/dev/sda3 udevadm settle --timeout=5 --exit-if-exists=/dev/sdb1 udevadm settle --timeout=5 --exit-if-exists=/dev/sdb2 udevadm settle --timeout=5 --exit-if-exists=/dev/sdb3 # Disable RAID recovery. We don't want this to slow down machine provisioning # in the rescue mode. It can run in normal operation after reboot. echo 0 > /proc/sys/dev/raid/speed_limit_max # LVM encrypt() { device=$1 label=$2 echo -n "$MAIN_PASSWORD" | cryptsetup luksFormat ${device}3 - echo -n "$MAIN_PASSWORD" | cryptsetup --key-file - open --type luks ${device}3 ${label}_encrypted } encrypt /dev/sda "a" encrypt /dev/sdb "b" # /boot partitions # ---------------- mkfs.fat -F 32 -n boot /dev/sda2 mkfs.fat -F 32 -n boot /dev/sdb2 # PVs pvcreate /dev/mapper/a_encrypted pvcreate /dev/mapper/b_encrypted # VGs vgcreate vg /dev/mapper/a_encrypted /dev/mapper/b_encrypted # LVs (--yes to automatically wipe detected file system signatures) # the root partition should be raid1 lvcreate --mirrors 1 --type raid1 -L 150G -n root vg # Filesystems (-F to not ask on preexisting FS) mkfs.ext4 -F -L root /dev/mapper/vg-root # Creating file systems changes their UUIDs. # Trigger udev so that the entries in /dev/disk/by-uuid get refreshed. # `nixos-generate-config` depends on those being up-to-date. # See https://github.com/NixOS/nixpkgs/issues/62444 udevadm trigger # Wait for FS labels to appear udevadm settle --timeout=5 --exit-if-exists=/dev/disk/by-label/root # NixOS pre-installation mounts # ----------------------------- # Mount target root partition mount /dev/disk/by-label/root /mnt mkdir -p /mnt/boot-{1,2} modprobe vfat mount /dev/sda2 /mnt/boot-1 mount /dev/sdb2 /mnt/boot-2 # Installing nix # -------------- # Installing nix requires `sudo`; the Hetzner rescue mode doesn't have it. apt-get install -y sudo # Allow installing nix as root, see # https://github.com/NixOS/nix/issues/936#issuecomment-475795730 mkdir -p /etc/nix echo "build-users-group =" > /etc/nix/nix.conf curl -L https://nixos.org/nix/install | sh set +u +x # sourcing this may refer to unset variables that we have no control over . $HOME/.nix-profile/etc/profile.d/nix.sh set -u -x # FIXME Keep in sync with `system.stateVersion` set below! nix-channel --add https://nixos.org/channels/nixos-21.05 nixpkgs nix-channel --update # Getting NixOS installation tools nix-env -iE "_: with import { configuration = {}; }; with config.system.build; [ nixos-generate-config nixos-install nixos-enter manual.manpages ]" nixos-generate-config --root /mnt # Detect # ------ # Find the name of the network interface that connects us to the Internet. # Inspired by https://unix.stackexchange.com/questions/14961/how-to-find-out-which-interface-am-i-using-for-connecting-to-the-internet/302613#302613 RESCUE_INTERFACE=$(ip route get 8.8.8.8 | grep -Po '(?<=dev )(\S+)') # Find what its name will be under NixOS, which uses stable interface names. # See https://major.io/2015/08/21/understanding-systemds-predictable-network-device-names/#comment-545626 # NICs for most Hetzner servers are not onboard, which is why we use # `ID_NET_NAME_PATH`otherwise it would be `ID_NET_NAME_ONBOARD`. INTERFACE_DEVICE_PATH=$(udevadm info -e | grep -Po "(?<=^P: )(.*${RESCUE_INTERFACE})") UDEVADM_PROPERTIES_FOR_INTERFACE=$(udevadm info --query=property "--path=$INTERFACE_DEVICE_PATH") NIXOS_INTERFACE=$(echo "$UDEVADM_PROPERTIES_FOR_INTERFACE" | grep -o -E 'ID_NET_NAME_PATH=\w+' | cut -d= -f2) echo "Determined NIXOS_INTERFACE as '$NIXOS_INTERFACE'" #NIXOS_INTERFACE='eth0' IP_V4=$(ip route get 8.8.8.8 | grep -Po '(?<=src )(\S+)') echo "Determined IP_V4 as $IP_V4" # Determine Internet IPv6 by checking route, and using ::1 # (because Hetzner rescue mode uses ::2 by default). # The `ip -6 route get` output on Hetzner looks like: # # ip -6 route get 2001:4860:4860:0:0:0:0:8888 # 2001:4860:4860::8888 via fe80::1 dev eth0 src 2a01:4f8:151:62aa::2 metric 1024 pref medium IP_V6="$(ip route get 2001:4860:4860:0:0:0:0:8888 | head -1 | cut -d' ' -f7 | cut -d: -f1-4)::1" echo "Determined IP_V6 as $IP_V6" # From https://stackoverflow.com/questions/1204629/how-do-i-get-the-default-gateway-in-linux-given-the-destination/15973156#15973156 read _ _ DEFAULT_GATEWAY _ < <(ip route list match 0/0); echo "$DEFAULT_GATEWAY" echo "Determined DEFAULT_GATEWAY as $DEFAULT_GATEWAY" # Generate `configuration.nix`. Note that we splice in shell variables. cat > /mnt/etc/nixos/configuration.nix < }; ipv6 = { address = "$IP_V6"; # the ipv6 addres gateway = "fe80::1"; # the ipv6 gateway prefixLength = 64; # shown in the control panel }; in { imports = [ # Include the results of the hardware scan. ./hardware-configuration.nix ]; # needed lvm for raid boot.initrd.kernelModules = [ "dm-snapshot" "dm_mirror" "dm_raid" "dm_region_hash" ]; # Use GRUB2 as the boot loader. # We don't use systemd-boot because Hetzner uses BIOS legacy boot. boot.loader.systemd-boot.enable = false; boot.loader.grub = { enable = true; efiSupport = false; version = 2; }; # This will mirror all UEFI files, kernels, grub menus and # things needed to boot to the other drive. boot.loader.grub.mirroredBoots = [ { path = "/boot-1"; devices = [ "/dev/sda" ]; } { path = "/boot-2"; devices = [ "/dev/sdb" ]; } ]; # We want to still be able to boot without one of these fileSystems."/boot-1".options = [ "nofail" ]; fileSystems."/boot-2".options = [ "nofail" ]; boot.initrd.luks.reusePassphrases = true; boot.initrd.luks.devices = { a_encrypted = { device = "/dev/sda3"; preLVM = true; }; b_encrypted = { device = "/dev/sdb3"; preLVM = true; }; }; networking.hostName = hostName; # Network configuration (Hetzner uses static IP assignments, and we don't use DHCP here) networking.useDHCP = false; networking.interfaces.\${networkInterface} = { ipv4 = { addresses = [{ address = ipv4.address; prefixLength = ipv4.prefixLength; }]; }; ipv6 = { addresses = [{ address = ipv6.address; prefixLength = ipv6.prefixLength; }]; }; }; networking.defaultGateway = ipv4.gateway; networking.defaultGateway6 = { address = ipv6.gateway; interface = networkInterface; }; networking.nameservers = [ "8.8.8.8" ]; # Initial empty root password for easy login: users.users.root.initialHashedPassword = ""; services.openssh.permitRootLogin = "prohibit-password"; users.users.root.openssh.authorizedKeys.keys = [ # FIXME : add ssh key "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQC6uza62+Go9sBFs3XZE2OkugBv9PJ7Yv8ebCskE5WYPcahMZIKkQw+zkGI8EGzOPJhQEv2xk+XBf2VOzj0Fto4nh8X5+Llb1nM+YxQPk1SVlwbNAlhh24L1w2vKtBtMy277MF4EP+caGceYP6gki5+DzlPUSdFSAEFFWgN1WPkiyUii15Xi3QuCMR8F18dbwVUYbT11vwNhdiAXWphrQG+yPguALBGR+21JM6fffOln3BhoDUp2poVc5Qe2EBuUbRUV3/fOU4HwWVKZ7KCFvLZBSVFutXCj5HuNWJ5T3RuuxJSmY5lYuFZx9gD+n+DAEJt30iXWcaJlmUqQB5awcB1S2d9pJ141V4vjiCMKUJHIdspFrI23rFNYD9k2ZXDA8VOnQE33BzmgF9xOVh6qr4G0oEpsNqJoKybVTUeSyl4+ifzdQANouvySgLJV/pcqaxX1srSDIUlcM2vDMWAs3ryCa0aAlmAVZIHgRhh6wa+IXW8gIYt+5biPWUuihJ4zGBEwkyVXXf2xsecMWCAGPWPDL0/fBfY9krNfC5M2sqxey2ShFIq+R/wMdaI7yVjUCF2QIUNiIdFbJL6bDrDyHnEXJJN+rAo23jUoTZZRv7Jq3DB/A5H7a73VCcblZyUmwMSlpg3wos7pdw5Ctta3zQPoxoAKGS1uZ+yTeZbPMmdbw==" ]; services.openssh.enable = true; system.stateVersion = "21.05"; # enable ssh on init # ------------------ boot.kernelParams = [ # See for docs on this # ip=::::::::: # The server ip refers to the NFS server -- we don't need it. "ip=\${ipv4.address}::\${ipv4.gateway}:\${ipv4.netmask}:\${hostName}-initrd:\${networkInterface}:off:8.8.8.8" ]; boot.initrd.availableKernelModules = [ networkInterfaceModule ]; boot.initrd.network.enable = true; boot.initrd.network.ssh = { enable = true; authorizedKeys = config.users.users.root.openssh.authorizedKeys.keys; port = 22; hostKeys = [ /etc/secrets/initrd/ssh_host_rsa_key /etc/secrets/initrd/ssh_host_ed25519_key ]; }; } EOF mkdir -p /mnt/etc/secrets/initrd/ ssh-keygen -t rsa -N "" -f /mnt/etc/secrets/initrd/ssh_host_rsa_key ssh-keygen -t ed25519 -N "" -f /mnt/etc/secrets/initrd/ssh_host_ed25519_key # Install NixOS #PATH="$PATH" NIX_PATH="$NIX_PATH" `which nixos-install` --no-root-passwd --root /mnt --max-jobs 40 PATH="$PATH" `which nixos-install` --no-root-passwd --root /mnt --max-jobs 40 umount /mnt/boot-{1,2} umount /mnt echo "Determined NIXOS_INTERFACE as '$NIXOS_INTERFACE'" echo "Determined IP_V4 as $IP_V4" echo "Determined IP_V6 as $IP_V6" echo "Determined DEFAULT_GATEWAY as $DEFAULT_GATEWAY" reboot