mirror of
https://github.com/elitak/nixos-infect.git
synced 2024-12-22 16:18:29 +03:00
186 lines
7.2 KiB
Bash
Executable file
186 lines
7.2 KiB
Bash
Executable file
#! /usr/bin/env bash
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# Use Digital Ocean Droplet image:
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#
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# Fedora 24 x64
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#
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# YMMV with any other hoster + image combination.
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# nixos-infect is so named because of the high likelihood of rendering a system
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# inoperable. Use with caution and preferably only on newly-provisioned
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# systems.
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#
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# WARNING NB This script wipes out the targeted host's root filesystem when it
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# runs to completion. Any errors halt execution. set -x is used to help debug,
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# as often a failed run leaves the system in an inconsistent state, requiring a
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# rebuild (in DigitalOcean panel: Droplet Settings -> "Destroy" -> "Rebuild
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# from original").
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#
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# TO USE:
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# - Add any custom config you want (see notes below)
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# - Deploy the droplet indicated at the top of the file, enable ipv6, add your ssh key
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# - cat customConfig.optional nixos-infect | ssh root@targethost
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#
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# Potential tweaks:
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# /etc/nixos/{,hardware-}configuration.nix : rudimentary mostly static config
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# /etc/nixos/networking.nix, networking settings determined at runtime
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# tweak if no ipv6, different number of adapters, etc.
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#
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# Motivation for this script: nixos-assimilate should supplant this script
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# entirely, if it's ever completed. nixos-in-place was quite broken when I
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# tried it, and also took a pretty janky approach that was substantially more
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# complex than this (although it supported more platforms): it didn't install
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# to root (/nixos instead), left dregs of the old filesystem (almost always
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# unnecessary since starting from a fresh deployment), and most importantly,
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# simply didn't work for me! (old system was being because grub wasnt properly
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# reinstalled)
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set -ex
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nixos_channel=nixos-unstable
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makeConf() {
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# NB <<"EOF" quotes / $ ` in heredocs, <<EOF does not
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mkdir -p /etc/nixos
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local IFS=$'\n'; keys=($(grep -vE '^[[:space:]]*(#|$)' /root/.ssh/authorized_keys))
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cat > /etc/nixos/configuration.nix << EOF
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{ ... }: {
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imports = [
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./hardware-configuration.nix
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./networking.nix # generated at runtime by nixos-infect
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];
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boot.cleanTmpDir = true;
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networking.hostName = "$(hostname)";
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networking.firewall.allowPing = true;
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services.openssh.enable = true;
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users.users.root.openssh.authorizedKeys.keys = [$(for key in ${keys[@]}; do echo -n "
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\"$key\""; done)
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];
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}
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EOF
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# (nixos-generate-config will add qemu-user and bind-mounts, so avoid)
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cat > /etc/nixos/hardware-configuration.nix << EOF
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{ ... }:
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{
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imports = [ <nixpkgs/nixos/modules/profiles/qemu-guest.nix> ];
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boot.loader.grub.device = "nodev";
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fileSystems."/" = { device = "/dev/vda1"; fsType = "ext4"; };
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}
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EOF
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local IFS=$'\n'
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ip4s=($(ip address show dev eth0 | grep 'inet ' | sed -r 's|.*inet ([0-9.]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|'))
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ip6s=($(ip address show dev eth0 | grep 'inet6 .*global' | sed -r 's|.*inet6 ([0-9a-f:]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|'))
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gateway=($(ip route show dev eth0 | grep default | sed -r 's|default via ([0-9.]+).*|\1|'))
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gateway6=($(ip -6 route show dev eth0 | grep default | sed -r 's|default via ([0-9a-f:]+).*|\1|'))
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ether0=($(ip address show dev eth0 | grep link/ether | sed -r 's|.*link/ether ([0-9a-f:]+) .*|\1|'))
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ether1=($(ip address show dev eth1 | grep link/ether | sed -r 's|.*link/ether ([0-9a-f:]+) .*|\1|'))
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nameservers=($(grep ^nameserver /etc/resolv.conf | cut -f2 -d' '))
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cat > /etc/nixos/networking.nix << EOF
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{ ... }: {
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# This file was populated at runtime with the networking
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# details gathered from the active system.
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networking = {
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nameservers = [$(for a in ${nameservers[@]}; do echo -n "
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\"$a\""; done)
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];
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defaultGateway = "${gateway}";
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defaultGateway6 = "${gateway6}";
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interfaces = {
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eth0 = {
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ip4 = [$(for a in ${ip4s[@]}; do echo -n "
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$a"; done)
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];
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ip6 = [$(for a in ${ip6s[@]}; do echo -n "
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$a"; done)
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];
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};
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# eth1 is for private networking or something?
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eth1.useDHCP = false;
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};
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};
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services.udev.extraRules = ''
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KERNEL=="eth*", ATTR{address}=="${ether0}", NAME="eth0"
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KERNEL=="eth*", ATTR{address}=="${ether1}", NAME="eth1"
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'';
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}
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EOF
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#! /usr/bin/env bash
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# NB put your semi-sensitive (not posted to github) configuration in a separate
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# file and include it via this customConfig() function. e.g.:
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# customConfig() {
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# cat > /etc/nixos/custom.nix << EOF
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# { config, lib, pkgs, ... }: {
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# }
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# EOF
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# }
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#
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# then you can add the files in configuration.nix's imports above and run something like:
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# cat customConfig nixos-infect | root@targethost bash
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if [[ `type -t customConfig` == "function" ]]; then customConfig; fi
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}
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makeSwap() {
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swapFile=`mktemp`
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dd if=/dev/zero of=$swapFile bs=1M count=$((1*1024))
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chmod 0600 $swapFile
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mkswap $swapFile
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swapon $swapFile
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}
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makeConf
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makeSwap # smallest (512MB) droplet needs extra memory!
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dnf install -y perl-Digest-SHA || true # Fedora 24
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groupadd -r nixbld
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seq 1 10 | xargs -I{} useradd -c "Nix build user {}" -d /var/empty -g nixbld -G nixbld -M -N -r -s `which nologin` nixbld{}
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curl https://nixos.org/nix/install | sh
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source ~/.nix-profile/etc/profile.d/nix.sh
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nix-channel --add https://nixos.org/channels/${nixos_channel} nixos
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nix-channel --update
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newRootImg=`mktemp`
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newRootMount=`mktemp -d`
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oldRootMount=`mktemp -d`
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export NIXOS_CONFIG=/etc/nixos/configuration.nix
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nix-env -i \
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-f /nix/var/nix/profiles/per-user/root/channels/nixpkgs/nixos \
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-A config.system.build.nixos-install
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# XXX GOTCHA NB bindmount causes /bin/bash permission BUG on many
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# versions (nix 1.10-1.11, nixpkgs 15-16), so we must use loopback image instead.
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# See: https://github.com/NixOS/nixpkgs/issues/10230
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dd if=/dev/zero of=$newRootImg bs=1M count=2047 # XXX 2048+ will cause mkfs.ext4 to fail on x86
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mkfs.ext4 -F $newRootImg
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mount $newRootImg $newRootMount
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rsync -Ra /./etc/nixos $newRootMount
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nixos-install --root $newRootMount
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mount -B / $oldRootMount
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# Everything up to this point is revertible; this is the truly destructive step.
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# GOTCHAs when running manually: very easy to forget slash at end of source, or use / as dest instead of bindmounted root, both of which are catastrophic...
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rsync -a --delete --exclude=$(dirname $newRootMount) $newRootMount/ $oldRootMount || true
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# Restore access to commands
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/nix/var/nix/profiles/system/activate # (this destroys resolv.conf)
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for ns in ${nameservers[@]}; do echo "nameserver $ns" >> /etc/resolv.conf; done
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source /nix/var/nix/profiles/system/etc/profile
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# grub/initrd was skipped with "nodev", because installing from inside install-root would result in wrong fs UUID, so we need a final rebuild
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sed -i 's,nodev,/dev/vda,' /etc/nixos/hardware-configuration.nix
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# TODO see aszlig's comment in issue about not even having to call rebuild, just nix-build system or something; without ever having to use nixos-install either? and separate ext4fs?
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# man nixos-rebuild mentions this!!: nixos-rebuid build == nix-build /path/to/nixpkgs/nixos -A system
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nixos-rebuild boot --install-grub || echo "WARNING: could not install grub, but we'll hope for the best: that the old installation of grub will manage to boot the new installation."
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sync
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echo "You may now Ctrl-C or otherwise terminate this process."
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reboot -f
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