372 lines
16 KiB
Bash
372 lines
16 KiB
Bash
#!/usr/bin/env bash
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# Installs NixOS on a Hetzner server, wiping the server.
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#
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# This is for a specific server configuration; adjust where needed.
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#
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# Prerequisites:
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# * this script requires ubuntu installed
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# * Update the script to put in your SSH pubkey, adjust hostname, NixOS version etc.
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# * have the following packages installed
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# * - zfs-initramfs
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# * - parted
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# * - sudo
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# * - grub-efi-amd64-bin
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cat > /etc/apt/preferences.d/90_zfs <<EOF
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Package: libnvpair1linux libuutil1linux libzfs2linux libzpool2linux spl-dkms zfs-dkms zfs-test zfsutils-linux zfsutils-linux-dev zfs-zed
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Pin: release n=buster-backports
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Pin-Priority: 990
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EOF
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apt update -y
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apt install -y dpkg-dev linux-headers-$(uname -r) linux-image-amd64 sudo parted zfs-dkms zfsutils-linux
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#
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# Usage:
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# ssh root@YOUR_SERVERS_IP bash -s < hetzner-dedicated-wipe-and-install-nixos.sh
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#
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# When the script is done, make sure to boot the server from HD, not rescue mode again.
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# Explanations:
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#
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# * Following largely https://nixos.org/nixos/manual/index.html#sec-installing-from-other-distro.
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# * and https://nixos.wiki/wiki/NixOS_on_ZFS
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# * **Important:** First you need to boot in legacy-BIOS mode. Then ask for
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# hetzner support to enable UEFI for you.
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# * We set a custom `configuration.nix` so that we can connect to the machine afterwards,
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# inspired by https://nixos.wiki/wiki/Install_NixOS_on_Hetzner_Online
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# * This server has 2 SSDs.
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# We put everything on mirror (RAID1 equivalent).
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# * A root user with empty password is created, so that you can just login
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# as root and press enter when using the Hetzner spider KVM.
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# Of course that empty-password login isn't exposed to the Internet.
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# Change the password afterwards to avoid anyone with physical access
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# being able to login without any authentication.
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# * The script reboots at the end.
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set -euox pipefail
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# Inspect existing disks
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# Should give you something like
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# NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
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# nvme0n1 259:0 0 476.9G 0 disk
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# ├─nvme0n1p1 259:2 0 32G 0 part
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# │ └─md0 9:0 0 32G 0 raid1 [SWAP]
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# ├─nvme0n1p2 259:3 0 512M 0 part
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# │ └─md1 9:1 0 511M 0 raid1 /boot
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# └─nvme0n1p3 259:4 0 444.4G 0 part
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# └─md2 9:2 0 444.3G 0 raid1 /
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# nvme1n1 259:1 0 476.9G 0 disk
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# ├─nvme1n1p1 259:5 0 32G 0 part
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# │ └─md0 9:0 0 32G 0 raid1 [SWAP]
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# ├─nvme1n1p2 259:6 0 512M 0 part
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# │ └─md1 9:1 0 511M 0 raid1 /boot
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# └─nvme1n1p3 259:7 0 444.4G 0 part
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# └─md2 9:2 0 444.3G 0 raid1 /
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lsblk
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# check the disks that you have available
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# you have to use disks by ID with zfs
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# see https://openzfs.github.io/openzfs-docs/Getting%20Started/Ubuntu/Ubuntu%2020.04%20Root%20on%20ZFS.html#step-2-disk-formatting
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ls /dev/disk/by-id
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# should give you something like this
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# md-name-rescue:0 nvme-eui.0025388a01051b58-part1
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# md-name-rescue:1 nvme-eui.0025388a01051b58-part2
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# md-name-rescue:2 nvme-eui.0025388a01051b58-part3
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# md-uuid-15391820:32e070f6:ecbfb99e:e983e018 nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00424
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# md-uuid-48379d14:3c44fe11:e6528eec:ad784ade nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00424-part1
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# md-uuid-f2a894fc:9e90e3af:9af81d28:b120ae1f nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00424-part2
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# nvme-eui.0025388a01051b55 nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00424-part3
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# nvme-eui.0025388a01051b55-part1 nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00427
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# nvme-eui.0025388a01051b55-part2 nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00427-part1
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# nvme-eui.0025388a01051b55-part3 nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00427-part2
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# nvme-eui.0025388a01051b58 nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00427-part3
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#
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# we will use the two disks
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# nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00424
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# nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00427
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# The following variables should be replaced
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DISK1=/dev/disk/by-id/nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00424
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DISK2=/dev/disk/by-id/nvme-SAMSUNG_MZVLB512HBJQ-00000_S4GENA0NA00427
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# Replace with your key
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SSH_PUB_KEY="ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGyQSeQ0CV/qhZPre37+Nd0E9eW+soGs+up6a/bwggoP raphael@RAPHAELs-MacBook-Pro.local"
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# choose whatever you want, it doesn't matter
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MY_HOSTNAME=hetzner-AX41-UEFI-ZFS-NVME
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MY_HOSTID=00000007
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# Undo existing setups to allow running the script multiple times to iterate on it.
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# We allow these operations to fail for the case the script runs the first time.
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umount /mnt || true
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vgchange -an || true
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# Stop all mdadm arrays that the boot may have activated.
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mdadm --stop --scan
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# Prevent mdadm from auto-assembling arrays.
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# Otherwise, as soon as we create the partition tables below, it will try to
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# re-assemple a previous RAID if any remaining RAID signatures are present,
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# before we even get the chance to wipe them.
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# From:
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# https://unix.stackexchange.com/questions/166688/prevent-debian-from-auto-assembling-raid-at-boot/504035#504035
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# We use `>` because the file may already contain some detected RAID arrays,
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# which would take precedence over our `<ignore>`.
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echo 'AUTO -all
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ARRAY <ignore> UUID=00000000:00000000:00000000:00000000' > /etc/mdadm/mdadm.conf
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# Create wrapper for parted >= 3.3 that does not exit 1 when it cannot inform
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# the kernel of partitions changing (we use partprobe for that).
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echo -e "#! /usr/bin/env bash\nset -e\n" 'parted $@ 2> parted-stderr.txt || grep "unable to inform the kernel of the change" parted-stderr.txt && echo "This is expected, continuing" || echo >&2 "Parted failed; stderr: $(< parted-stderr.txt)"' > parted-ignoring-partprobe-error.sh && chmod +x parted-ignoring-partprobe-error.sh
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# Create partition tables (--script to not ask)
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./parted-ignoring-partprobe-error.sh --script $DISK1 mklabel gpt
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./parted-ignoring-partprobe-error.sh --script $DISK2 mklabel gpt
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# Create partitions (--script to not ask)
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#
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# We create the 1MB BIOS boot partition at the front.
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#
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# Note we use "MB" instead of "MiB" because otherwise `--align optimal` has no effect;
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# as per documentation https://www.gnu.org/software/parted/manual/html_node/unit.html#unit:
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# > Note that as of parted-2.4, when you specify start and/or end values using IEC
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# > binary units like "MiB", "GiB", "TiB", etc., parted treats those values as exact
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#
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# Note: When using `mkpart` on GPT, as per
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# https://www.gnu.org/software/parted/manual/html_node/mkpart.html#mkpart
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# the first argument to `mkpart` is not a `part-type`, but the GPT partition name:
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# ... part-type is one of 'primary', 'extended' or 'logical', and may be specified only with 'msdos' or 'dvh' partition tables.
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# A name must be specified for a 'gpt' partition table.
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# GPT partition names are limited to 36 UTF-16 chars, see https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_entries_(LBA_2-33).
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# TODO the bios partition should not be this big
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# however if it's less the installation fails with
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# cannot copy /nix/store/d4xbrrailkn179cdp90v4m57mqd73hvh-linux-5.4.100/bzImage to /boot/kernels/d4xbrrailkn179cdp90v4m57mqd73hvh-linux-5.4.100-bzImage.tmp: No space left on device
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./parted-ignoring-partprobe-error.sh --script --align optimal $DISK1 -- mklabel gpt \
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mkpart 'BIOS-boot-partition' 1MB 2MB set 1 bios_grub on \
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mkpart 'EFI-system-partition' 2MB 512MB set 2 esp on \
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mkpart 'data-partition' 512MB '100%'
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./parted-ignoring-partprobe-error.sh --script --align optimal $DISK2 -- mklabel gpt \
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mkpart 'BIOS-boot-partition' 1MB 2MB set 1 bios_grub on \
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mkpart 'EFI-system-partition' 2MB 512MB set 2 esp on \
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mkpart 'data-partition' 512MB '100%'
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# Reload partitions
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partprobe
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# Wait for all devices to exist
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udevadm settle --timeout=5 --exit-if-exists=$DISK1-part1
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udevadm settle --timeout=5 --exit-if-exists=$DISK1-part2
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udevadm settle --timeout=5 --exit-if-exists=$DISK1-part3
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udevadm settle --timeout=5 --exit-if-exists=$DISK2-part1
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udevadm settle --timeout=5 --exit-if-exists=$DISK2-part2
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udevadm settle --timeout=5 --exit-if-exists=$DISK2-part3
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# Wipe any previous RAID signatures
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# somehow the previous RAID signature is only on part1
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mdadm --zero-superblock --force $DISK1-part1
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mdadm --zero-superblock --force $DISK2-part1
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# Creating file systems changes their UUIDs.
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# Trigger udev so that the entries in /dev/disk/by-uuid get refreshed.
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# `nixos-generate-config` depends on those being up-to-date.
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# See https://github.com/NixOS/nixpkgs/issues/62444
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udevadm trigger
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# taken from https://nixos.wiki/wiki/NixOS_on_ZFS
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zpool create -O mountpoint=none \
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-O atime=off \
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-O compression=lz4 \
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-O xattr=sa \
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-O acltype=posixacl \
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-o ashift=12 \
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-f \
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rpool mirror $DISK1-part3 $DISK2-part3
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# Create the filesystems. This layout is designed so that /home is separate from the root
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# filesystem, as you'll likely want to snapshot it differently for backup purposes. It also
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# makes a "nixos" filesystem underneath the root, to support installing multiple OSes if
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# that's something you choose to do in future.
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zfs create -o mountpoint=legacy rpool/root
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zfs create -o mountpoint=legacy rpool/root/nixos
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zfs create -o mountpoint=legacy rpool/home
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# add 1G of reseved space in case the disk gets full
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# zfs needs space to delete files
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zfs create -o refreservation=1G -o mountpoint=none rpool/reserved
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# this creates a special volume for db data see https://wiki.archlinux.org/index.php/ZFS#Databases
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zfs create -o mountpoint=legacy \
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-o recordsize=8K \
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-o primarycache=metadata \
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-o logbias=throughput \
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rpool/postgres
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# NixOS pre-installation mounts
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#
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# Mount the filesystems manually. The nixos installer will detect these mountpoints
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# and save them to /mnt/nixos/hardware-configuration.nix during the install process.
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mount -t zfs rpool/root/nixos /mnt
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mkdir /mnt/home
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mount -t zfs rpool/home /mnt/home
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mkdir -p /mnt/var/lib/postgres
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mount -t zfs rpool/postgres /mnt/var/lib/postgres
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# Create a raid mirror for the efi boot
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# see https://docs.hetzner.com/robot/dedicated-server/operating-systems/efi-system-partition/
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# TODO check this though the following article says it doesn't work properly
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# https://outflux.net/blog/archives/2018/04/19/uefi-booting-and-raid1/
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mdadm --create --run --verbose /dev/md127 \
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--level 1 \
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--raid-disks 2 \
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--metadata 1.0 \
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--homehost=$MY_HOSTNAME \
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--name=boot_efi \
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$DISK1-part2 $DISK2-part2
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# Assembling the RAID can result in auto-activation of previously-existing LVM
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# groups, preventing the RAID block device wiping below with
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# `Device or resource busy`. So disable all VGs first.
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vgchange -an
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# Wipe filesystem signatures that might be on the RAID from some
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# possibly existing older use of the disks (RAID creation does not do that).
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# See https://serverfault.com/questions/911370/why-does-mdadm-zero-superblock-preserve-file-system-information
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wipefs -a /dev/md127
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# Disable RAID recovery. We don't want this to slow down machine provisioning
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# in the rescue mode. It can run in normal operation after reboot.
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echo 0 > /proc/sys/dev/raid/speed_limit_max
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# Filesystems (-F to not ask on preexisting FS)
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mkfs.vfat -F 32 /dev/md127
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# Creating file systems changes their UUIDs.
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# Trigger udev so that the entries in /dev/disk/by-uuid get refreshed.
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# `nixos-generate-config` depends on those being up-to-date.
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# See https://github.com/NixOS/nixpkgs/issues/62444
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udevadm trigger
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mkdir -p /mnt/boot/efi
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mount /dev/md127 /mnt/boot/efi
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# Installing nix
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# Allow installing nix as root, see
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# https://github.com/NixOS/nix/issues/936#issuecomment-475795730
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mkdir -p /etc/nix
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echo "build-users-group =" > /etc/nix/nix.conf
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# TODO
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# warning: installing Nix as root is not supported by this script!
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curl -L https://nixos.org/nix/install | sh
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set +u +x # sourcing this may refer to unset variables that we have no control over
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. $HOME/.nix-profile/etc/profile.d/nix.sh
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set -u -x
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# Keep in sync with `system.stateVersion` set below!
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nix-channel --add https://nixos.org/channels/nixos-20.09 nixpkgs
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nix-channel --update
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# Getting NixOS installation tools
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nix-env -iE "_: with import <nixpkgs/nixos> { configuration = {}; }; with config.system.build; [ nixos-generate-config nixos-install nixos-enter manual.manpages ]"
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# TODO
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# perl: warning: Please check that your locale settings:
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# LANGUAGE = (unset),
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# LC_ALL = "en_US.UTF-8",
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# LANG = "en_US.UTF-8"
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# are supported and installed on your system.
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nixos-generate-config --root /mnt
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# Find the name of the network interface that connects us to the Internet.
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# Inspired by https://unix.stackexchange.com/questions/14961/how-to-find-out-which-interface-am-i-using-for-connecting-to-the-internet/302613#302613
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RESCUE_INTERFACE=$(ip route get 8.8.8.8 | grep -Po '(?<=dev )(\S+)')
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# Find what its name will be under NixOS, which uses stable interface names.
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# See https://major.io/2015/08/21/understanding-systemds-predictable-network-device-names/#comment-545626
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# NICs for most Hetzner servers are not onboard, which is why we use
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# `ID_NET_NAME_PATH`otherwise it would be `ID_NET_NAME_ONBOARD`.
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INTERFACE_DEVICE_PATH=$(udevadm info -e | grep -Po "(?<=^P: )(.*${RESCUE_INTERFACE})")
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UDEVADM_PROPERTIES_FOR_INTERFACE=$(udevadm info --query=property "--path=$INTERFACE_DEVICE_PATH")
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NIXOS_INTERFACE=$(echo "$UDEVADM_PROPERTIES_FOR_INTERFACE" | grep -o -E 'ID_NET_NAME_PATH=\w+' | cut -d= -f2)
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echo "Determined NIXOS_INTERFACE as '$NIXOS_INTERFACE'"
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IP_V4=$(ip route get 8.8.8.8 | grep -Po '(?<=src )(\S+)')
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echo "Determined IP_V4 as $IP_V4"
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# Determine Internet IPv6 by checking route, and using ::1
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# (because Hetzner rescue mode uses ::2 by default).
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# The `ip -6 route get` output on Hetzner looks like:
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# # ip -6 route get 2001:4860:4860:0:0:0:0:8888
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# 2001:4860:4860::8888 via fe80::1 dev eth0 src 2a01:4f8:151:62aa::2 metric 1024 pref medium
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IP_V6="$(ip route get 2001:4860:4860:0:0:0:0:8888 | head -1 | cut -d' ' -f7 | cut -d: -f1-4)::1"
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echo "Determined IP_V6 as $IP_V6"
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# From https://stackoverflow.com/questions/1204629/how-do-i-get-the-default-gateway-in-linux-given-the-destination/15973156#15973156
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read _ _ DEFAULT_GATEWAY _ < <(ip route list match 0/0); echo "$DEFAULT_GATEWAY"
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echo "Determined DEFAULT_GATEWAY as $DEFAULT_GATEWAY"
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# Generate `configuration.nix`. Note that we splice in shell variables.
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cat > /mnt/etc/nixos/configuration.nix <<EOF
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{ config, pkgs, ... }:
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{
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imports =
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[ # Include the results of the hardware scan.
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./hardware-configuration.nix
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];
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# Use GRUB2 as the boot loader.
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# We don't use systemd-boot because Hetzner uses BIOS legacy boot.
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boot.loader.systemd-boot.enable = false;
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boot.loader.grub = {
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enable = true;
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efiSupport = false;
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devices = ["$DISK1" "$DISK2"];
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copyKernels = true;
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};
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boot.supportedFilesystems = [ "zfs" ];
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networking.hostName = "$MY_HOSTNAME";
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networking.hostId = "$MY_HOSTID";
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# Network (Hetzner uses static IP assignments, and we don't use DHCP here)
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networking.useDHCP = false;
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networking.interfaces."$NIXOS_INTERFACE".ipv4.addresses = [
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{
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address = "$IP_V4";
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prefixLength = 24;
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}
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];
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networking.interfaces."$NIXOS_INTERFACE".ipv6.addresses = [
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{
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address = "$IP_V6";
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prefixLength = 64;
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}
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];
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networking.defaultGateway = "$DEFAULT_GATEWAY";
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networking.defaultGateway6 = { address = "fe80::1"; interface = "$NIXOS_INTERFACE"; };
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networking.nameservers = [ "8.8.8.8" ];
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# Initial empty root password for easy login:
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users.users.root.initialHashedPassword = "";
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services.openssh.permitRootLogin = "prohibit-password";
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users.users.root.openssh.authorizedKeys.keys = ["$SSH_PUB_KEY"];
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services.openssh.enable = true;
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# This value determines the NixOS release with which your system is to be
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# compatible, in order to avoid breaking some software such as database
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# servers. You should change this only after NixOS release notes say you
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# should.
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system.stateVersion = "20.09"; # Did you read the comment?
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}
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EOF
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# Install NixOS
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PATH="$PATH" NIX_PATH="$NIX_PATH" `which nixos-install` \
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--no-root-passwd --root /mnt --max-jobs 40
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umount /mnt
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reboot
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