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Diffstat (limited to 'nix/hosts/corrino/hetzner-dedicated-wipe-and-install-nixos-luks-raid-lvm.sh')
| -rwxr-xr-x | nix/hosts/corrino/hetzner-dedicated-wipe-and-install-nixos-luks-raid-lvm.sh | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/nix/hosts/corrino/hetzner-dedicated-wipe-and-install-nixos-luks-raid-lvm.sh b/nix/hosts/corrino/hetzner-dedicated-wipe-and-install-nixos-luks-raid-lvm.sh new file mode 100755 index 0000000..de42261 --- /dev/null +++ b/nix/hosts/corrino/hetzner-dedicated-wipe-and-install-nixos-luks-raid-lvm.sh @@ -0,0 +1,347 @@ +#!/usr/bin/env bash + +# 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 put everything on RAID1. +# Storage scheme: `partitions -> RAID -> LVM -> ext4`. +# * 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. + +NIXOS_VERSION="22.11" + +echo "Enter New Hostname" +HOSTNAME="corrino" + +echo "Enter LUKS Password" +LUKS_PASSWORD="FIXME" + +set -eu +set -o pipefail + +set -x + +# Inspect existing disks +lsblk + +# 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 /mnt/dev /mnt/proc /mnt/run /mnt/sys /mnt +vgchange -an +cryptsetup close luks0 +rm initrd_ssh_host_ecdsa_key +set -e + +# Stop all mdadm arrays that the boot may have activated. +mdadm --stop --scan + +# Prevent mdadm from auto-assembling arrays. +# Otherwise, as soon as we create the partition tables below, it will try to +# re-assemple a previous RAID if any remaining RAID signatures are present, +# before we even get the chance to wipe them. +# From: +# https://unix.stackexchange.com/questions/166688/prevent-debian-from-auto-assembling-raid-at-boot/504035#504035 +# We use `>` because the file may already contain some detected RAID arrays, +# which would take precedence over our `<ignore>`. +echo 'AUTO -all +ARRAY <ignore> UUID=00000000:00000000:00000000:00000000' > /etc/mdadm/mdadm.conf + +# Create partition tables (--script to not ask) +parted --script /dev/nvme0n1 mklabel gpt +parted --script /dev/nvme1n1 mklabel gpt + +# Create partitions (--script to not ask) +# +# We create the 1MB BIOS boot partition at the front. +# +# Note we use "MB" instead of "MiB" because otherwise `--align optimal` has no effect; +# as per documentation https://www.gnu.org/software/parted/manual/html_node/unit.html#unit: +# > Note that as of parted-2.4, when you specify start and/or end values using IEC +# > binary units like "MiB", "GiB", "TiB", etc., parted treats those values as exact +# +# Note: When using `mkpart` on GPT, as per +# https://www.gnu.org/software/parted/manual/html_node/mkpart.html#mkpart +# the first argument to `mkpart` is not a `part-type`, but the GPT partition name: +# ... part-type is one of 'primary', 'extended' or 'logical', and may be specified only with 'msdos' or 'dvh' partition tables. +# A name must be specified for a 'gpt' partition table. +# GPT partition names are limited to 36 UTF-16 chars, see https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_entries_(LBA_2-33). +parted --script --align optimal /dev/nvme0n1 -- mklabel gpt mkpart 'bios' 1MB 2MB set 1 bios_grub on mkpart 'boot' 2MB 1000MB mkpart 'root' 1000MB '100%' +parted --script --align optimal /dev/nvme1n1 -- mklabel gpt mkpart 'bios' 1MB 2MB set 1 bios_grub on mkpart 'boot' 2MB 1000MB mkpart 'root' 1000MB '100%' + +# Relaod partitions +partprobe + +# Wait for all devices to exist +udevadm settle --timeout=5 --exit-if-exists=/dev/nvme0n1p1 +udevadm settle --timeout=5 --exit-if-exists=/dev/nvme0n1p2 +udevadm settle --timeout=5 --exit-if-exists=/dev/nvme0n1p3 + +udevadm settle --timeout=5 --exit-if-exists=/dev/nvme1n1p1 +udevadm settle --timeout=5 --exit-if-exists=/dev/nvme1n1p2 +udevadm settle --timeout=5 --exit-if-exists=/dev/nvme1n1p3 + +# Wipe any previous RAID signatures +mdadm --zero-superblock --force /dev/nvme0n1p2 +mdadm --zero-superblock --force /dev/nvme0n1p3 +mdadm --zero-superblock --force /dev/nvme1n1p2 +mdadm --zero-superblock --force /dev/nvme1n1p3 + +# Create RAIDs +# Note that during creating and boot-time assembly, mdadm cares about the +# host name, and the existence and contents of `mdadm.conf`! +# This also affects the names appearing in /dev/md/ being different +# before and after reboot in general (but we take extra care here +# to pass explicit names, and set HOMEHOST for the rebooting system further +# down, so that the names appear the same). +# Almost all details of this are explained in +# https://bugzilla.redhat.com/show_bug.cgi?id=606481#c14 +# and the followup comments by Doug Ledford. +#mdadm --create --run --verbose /dev/md0 --level=1 --raid-devices=2 --homehost=lxc11 --name=root0 /dev/nvme0n1p2 /dev/nvme1n1p2 +mdadm --create --run --verbose /dev/md0 --level=1 --raid-devices=2 --homehost=$HOSTNAME --name=md0 /dev/nvme0n1p2 /dev/nvme1n1p2 +mdadm --create --run --verbose /dev/md1 --level=1 --raid-devices=2 --homehost=$HOSTNAME --name=md1 /dev/nvme0n1p3 /dev/nvme1n1p3 + +# Assembling the RAID can result in auto-activation of previously-existing LVM +# groups, preventing the RAID block device wiping below with +# `Device or resource busy`. So disable all VGs first. +vgchange -an + +# Wipe filesystem signatures that might be on the RAID from some +# possibly existing older use of the disks (RAID creation does not do that). +# See https://serverfault.com/questions/911370/why-does-mdadm-zero-superblock-preserve-file-system-information +wipefs -a /dev/md0 +wipefs -a /dev/md1 + +# 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 + +# LUKS +echo "$LUKS_PASSWORD" | cryptsetup luksFormat --type luks2 -h sha512 /dev/md1 +echo "$LUKS_PASSWORD" | cryptsetup luksOpen /dev/md1 luks0 + +# LVM +# PVs +pvcreate /dev/mapper/luks0 +#pvcreate /dev/md0 + +# VGs +#vgcreate vg0 /dev/md0 +vgcreate vg0 /dev/mapper/luks0 + +# LVs (--yes to automatically wipe detected file system signatures) +lvcreate --yes --extents 95%FREE -n root vg0 # 5% slack space + +# Filesystems (-F to not ask on preexisting FS) +mkfs.ext4 -F -L boot /dev/md0 +mkfs.ext4 -F -L root /dev/vg0/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/boot +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 /mnt/boot +mount /dev/disk/by-label/boot /mnt/boot + +# 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 +. $HOME/.nix-profile/etc/profile.d/nix.sh +set -u -x + +# FIXME Keep in sync with `system.stateVersion` set below! +nix-channel --add https://nixos.org/channels/nixos-$NIXOS_VERSION nixpkgs +nix-channel --update + +# Getting NixOS installation tools +nix-env -iE "_: with import <nixpkgs/nixos> { configuration = {}; }; with config.system.build; [ nixos-generate-config nixos-install nixos-enter manual.manpages ]" + +nixos-generate-config --root /mnt + +# 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'" +# DOESNT WORK on PX server there it was eno1 + +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 $DEFAULT_GATEWAY" + +# Generate `configuration.nix`. Note that we splice in shell variables. +cat > /mnt/etc/nixos/configuration.nix <<EOF +{ config, pkgs, lib, ... }: +{ + imports = + [ # Include the results of the hardware scan. + ./hardware-configuration.nix + ]; + # Use GRUB2 as the boot loader. + # We don't use systemd-boot because Hetzner uses BIOS legacy boot. + boot.loader.systemd-boot.enable = false; + + boot.loader.grub = { + enable = true; + efiSupport = false; + version = 2; + enableCryptodisk = true; + device = "nodev"; + devices = [ "/dev/nvme0n1" "/dev/nvme1n1"]; + }; + networking.hostName = "$HOSTNAME"; + boot.initrd.kernelModules = [ "dm-snapshot" ]; + boot.initrd.availableKernelModules = [ "cryptd" "aesni_intel" "igb" ];#"FIXME Your network driver" ]; + boot.initrd.network = { + enable = true; + ssh = { + enable = true; + + # ssh port during boot for luks decryption + port = 2222; + authorizedKeys = config.users.users.root.openssh.authorizedKeys.keys; + hostKeys = [ "/initrd_ssh_host_ecdsa_key" ]; + }; + postCommands = '' + echo 'cryptsetup-askpass' >> /root/.profile + ''; + }; + boot.kernelParams = [ "ip=$IP_V4::$DEFAULT_GATEWAY:255.255.255.192:$HOSTNAME:$NIXOS_INTERFACE:off:8.8.8.8:8.8.4.4:" ]; + boot.loader.supportsInitrdSecrets = true; + boot.initrd.luks.forceLuksSupportInInitrd = true; + boot.initrd.luks.devices = { + root = { + preLVM = true; + device = "/dev/md1"; + allowDiscards = true; + }; + }; + + boot.initrd.secrets = { + "/initrd_ssh_host_ecdsa_key" = "/initrd_ssh_host_ecdsa_key"; + }; + # The mdadm RAID1s were created with 'mdadm --create ... --homehost=hetzner', + # but the hostname for each machine may be different, and mdadm's HOMEHOST + # setting defaults to '<system>' (using the system hostname). + # This results mdadm considering such disks as "foreign" as opposed to + # "local", and showing them as e.g. '/dev/md/hetzner:root0' + # instead of '/dev/md/root0'. + # This is mdadm's protection against accidentally putting a RAID disk + # into the wrong machine and corrupting data by accidental sync, see + # https://bugzilla.redhat.com/show_bug.cgi?id=606481#c14 and onward. + # We do not worry about plugging disks into the wrong machine because + # we will never exchange disks between machines, so we tell mdadm to + # ignore the homehost entirely. + environment.etc."mdadm.conf".text = '' + HOMEHOST <ignore> + ''; + # The RAIDs are assembled in stage1, so we need to make the config + # available there. + boot.initrd.services.swraid.mdadmConf = config.environment.etc."mdadm.conf".text; + # Network (Hetzner uses static IP assignments, and we don't use DHCP here) + networking.useDHCP = false; + networking.interfaces."$NIXOS_INTERFACE".ipv4.addresses = [ + { + address = "$IP_V4"; + + # FIXME Lookup for right netmask prefix length within rescu system + prefixLength = 26; + } + ]; + networking.interfaces."$NIXOS_INTERFACE".ipv6.addresses = [ + { + address = "$IP_V6"; + prefixLength = 64; + } + ]; + networking.defaultGateway = "$DEFAULT_GATEWAY"; + networking.defaultGateway6 = { address = "fe80::1"; interface = "$NIXOS_INTERFACE"; }; + networking.nameservers = [ "8.8.8.8" "8.8.4.4" ]; + # Initial empty root password for easy login: + users.users.root.initialHashedPassword = ""; + services.openssh.permitRootLogin = "prohibit-password"; + users.users.root.openssh.authorizedKeys.keys = [ + # FIXME Replace this by your SSH pubkey! + "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPZi43zHEsoWaQomLGaftPE5k0RqVrZyiTtGqZlpWsew" + ]; + services.openssh.enable = true; + + # FIXME + # This value determines the NixOS release with which your system is to be + # compatible, in order to avoid breaking some software such as database + # servers. You should change this only after NixOS release notes say you + # should. + system.stateVersion = "$NIXOS_VERSION"; # Did you read the comment? +} +EOF + +ssh-keygen -t ecdsa -N "" -f initrd_ssh_host_ecdsa_key; +cp initrd_ssh_host_ecdsa_key /mnt/initrd_ssh_host_ecdsa_key; + +# Install NixOS +PATH="$PATH" `which nixos-install` --no-root-passwd --root /mnt --max-jobs 40 + +umount /mnt/boot +umount /mnt + +echo "DONE" |
