nixos-infect/nixos-infect
2017-02-14 00:18:59 -08:00

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#! /usr/bin/env bash
# These are the only supported Digital Ocean images:
#
# Fedora 24 x64
# Ubuntu 16.04 x64
# Debian 8.5 x64
#
# YMMV with any other hoster + image combination.
# nixos-infect is so named because of the high likelihood of rendering a system
# inoperable. Use with caution and preferably only on newly-provisioned
# systems.
#
# WARNING NB This script wipes out the targeted host's root filesystem when it
# runs to completion. Any errors halt execution. set -x is used to help debug,
# as often a failed run leaves the system in an inconsistent state, requiring a
# rebuild (in DigitalOcean panel: Droplet Settings -> "Destroy" -> "Rebuild
# from original").
#
# TO USE:
# - Add any custom config you want (see notes below)
# - Deploy the droplet indicated at the top of the file, enable ipv6, add your ssh key
# - cat customConfig.optional nixos-infect | ssh root@targethost
#
# Alternatively, use the user data mechamism by supplying the following lines (without >)
# in the Digital Ocean Web UI (or HTTP API):
#
# > #cloud-config
# >
# > runcmd:
# > - curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | bash 2>&1 | tee /tmp/infect.log
#
# Potential tweaks:
# /etc/nixos/{,hardware-}configuration.nix : rudimentary mostly static config
# /etc/nixos/networking.nix, networking settings determined at runtime
# tweak if no ipv6, different number of adapters, etc.
#
# Motivation for this script: nixos-assimilate should supplant this script
# entirely, if it's ever completed. nixos-in-place was quite broken when I
# tried it, and also took a pretty janky approach that was substantially more
# complex than this (although it supported more platforms): it didn't install
# to root (/nixos instead), left dregs of the old filesystem (almost always
# unnecessary since starting from a fresh deployment), and most importantly,
# simply didn't work for me! (old system was being because grub wasnt properly
# reinstalled)
set -ex -o pipefail
makeConf() {
# NB <<"EOF" quotes / $ ` in heredocs, <<EOF does not
mkdir -p /etc/nixos
local IFS=$'\n'; keys=($(grep -vE '^[[:space:]]*(#|$)' /root/.ssh/authorized_keys))
cat > /etc/nixos/configuration.nix << EOF
{ ... }: {
imports = [
./hardware-configuration.nix
./networking.nix # generated at runtime by nixos-infect
];
boot.cleanTmpDir = true;
networking.hostName = "$(hostname)";
networking.firewall.allowPing = true;
services.openssh.enable = true;
users.users.root.openssh.authorizedKeys.keys = [$(for key in ${keys[@]}; do echo -n "
\"$key\""; done)
];
}
EOF
# (nixos-generate-config will add qemu-user and bind-mounts, so avoid)
cat > /etc/nixos/hardware-configuration.nix << EOF
{ ... }:
{
imports = [ <nixpkgs/nixos/modules/profiles/qemu-guest.nix> ];
boot.loader.grub.device = "/dev/$disk";
fileSystems."/" = { device = "/dev/${disk}1"; fsType = "ext4"; };
}
EOF
local IFS=$'\n'
eth0_ip4s=($(ip address show dev eth0 | grep 'inet ' | sed -r 's|.*inet ([0-9.]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|'))
eth0_ip6s=($(ip address show dev eth0 | grep 'inet6 .*global' | sed -r 's|.*inet6 ([0-9a-f:]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|'))
eth1_ip4s=($(ip address show dev eth1 | grep 'inet ' | sed -r 's|.*inet ([0-9.]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|'))
eth1_ip6s=($(ip address show dev eth1 | grep 'inet6 .*global' | sed -r 's|.*inet6 ([0-9a-f:]+)/([0-9]+).*|{ address="\1"; prefixLength=\2; }|'))
gateway=($(ip route show dev eth0 | grep default | sed -r 's|default via ([0-9.]+).*|\1|'))
gateway6=($(ip -6 route show dev eth0 | grep default | sed -r 's|default via ([0-9a-f:]+).*|\1|'))
ether0=($(ip address show dev eth0 | grep link/ether | sed -r 's|.*link/ether ([0-9a-f:]+) .*|\1|'))
ether1=($(ip address show dev eth1 | grep link/ether | sed -r 's|.*link/ether ([0-9a-f:]+) .*|\1|'))
nameservers=($(grep ^nameserver /etc/resolv.conf | cut -f2 -d' '))
cat > /etc/nixos/networking.nix << EOF
{ ... }: {
# This file was populated at runtime with the networking
# details gathered from the active system.
networking = {
nameservers = [$(for a in ${nameservers[@]}; do echo -n "
\"$a\""; done)
];
defaultGateway = "${gateway}";
defaultGateway6 = "${gateway6}";
interfaces = {
eth0 = {
ip4 = [$(for a in ${eth0_ip4s[@]}; do echo -n "
$a"; done)
];
ip6 = [$(for a in ${eth1_ip6s[@]}; do echo -n "
$a"; done)
];
};
eth1 = {
ip4 = [$(for a in ${eth1_ip4s[@]}; do echo -n "
$a"; done)
];
ip6 = [$(for a in ${eth1_ip6s[@]}; do echo -n "
$a"; done)
];
};
};
};
services.udev.extraRules = ''
KERNEL=="eth*", ATTR{address}=="${ether0}", NAME="eth0"
KERNEL=="eth*", ATTR{address}=="${ether1}", NAME="eth1"
'';
}
EOF
#! /usr/bin/env bash
# NB put your semi-sensitive (not posted to github) configuration in a separate
# file and include it via this customConfig() function. e.g.:
# customConfig() {
# cat > /etc/nixos/custom.nix << EOF
# { config, lib, pkgs, ... }: {
# }
# EOF
# }
#
# then you can add the files in configuration.nix's imports above and run something like:
# cat customConfig nixos-infect | root@targethost bash
if [[ "$(type -t customConfig)" == "function" ]]; then customConfig; fi
}
makeSwap() {
# TODO check currently available swapspace first
swapFile=`mktemp`
dd if=/dev/zero of=$swapFile bs=1M count=$((1*1024))
chmod 0600 $swapFile
mkswap $swapFile
swapon $swapFile
}
prepareEnv() {
# $disk is used in makeConf()
for disk in vda sda; do [[ -e /dev/$disk ]] && break; done
# DigitalOcean doesn't seem to set USER while running user data
export USER="root"
export HOME="/root"
# Use adapted wget if curl is missing
which curl || { \
curl() {
eval "wget $(
(local isStdout=1
for arg in "$@"; do
case "$arg" in
"-o")
echo "-O";
isStdout=0
;;
"-O")
isStdout=0
;;
"-L")
;;
*)
echo "$arg"
;;
esac
done;
[[ $isStdout -eq 1 ]] && echo "-O-"
)| tr '\n' ' '
)"
}; export -f curl; }
# Nix installer tries to use sudo regardless of whether we're already uid 0
#which sudo || { sudo() { eval "$@"; }; export -f sudo; }
mkdir -p -m 0755 /nix
}
req() {
type "$1" > /dev/null 2>&1 || which "$1" > /dev/null 2>&1
}
checkEnv() {
# Perform some easy fixups before checking
which dnf && dnf install -y perl-Digest-SHA # Fedora 24
which bzcat || (which yum && yum install -y bzip2) # CentOS
[[ "$(whoami)" == "root" ]] || { echo "ERROR: Must run as root"; return 1; }
( req curl || req wget || echo "ERROR: Missing both curl and wget" ) && \
( req bzcat || echo "ERROR: Missing bzcat" ) && \
( req perl || echo "ERROR: Missing perl" ) && \
( req groupadd || echo "ERROR: Missing groupadd" ) && \
( req useradd || echo "ERROR: Missing useradd" ) \
|| return 1
}
infect() {
# Add nix build users
# FIXME run only if necessary, rather than defaulting true
groupadd -r nixbld -g 30000 || true
for i in {1..10}; do useradd -c "Nix build user $i" -d /var/empty -g nixbld -G nixbld -M -N -r -s $(which nologin) nixbld$i || true; done
curl https://nixos.org/nix/install | $SHELL
source ~/.nix-profile/etc/profile.d/nix.sh
[[ -z "$NIX_CHANNEL" ]] && NIX_CHANNEL="nixos-16.09"
nix-channel --remove nixpkgs
nix-channel --add "https://nixos.org/channels/$NIX_CHANNEL" nixos
nix-channel --update
export NIXOS_CONFIG=/etc/nixos/configuration.nix
nix-env --set \
-I nixpkgs=$HOME/.nix-defexpr/channels/nixos \
-f '<nixpkgs/nixos>' \
-p /nix/var/nix/profiles/system \
-A system
# Remove nix installed with curl | bash
rm -fv /nix/var/nix/profiles/default*
/nix/var/nix/profiles/system/sw/bin/nix-collect-garbage
# Reify resolv.conf
[[ -L /etc/resolv.conf ]] && mv -v /etc/resolv.conf /etc/resolv.conf.lnk && cat /etc/resolv.conf.lnk > /etc/resolv.conf
# Stage the Nix coup d'état
touch /etc/NIXOS
echo etc/nixos > /etc/NIXOS_LUSTRATE
echo etc/resolv.conf >> /etc/NIXOS_LUSTRATE
echo root/.nix-defexpr/channels >> /etc/NIXOS_LUSTRATE
rm -rf /boot.bak && mv -v /boot /boot.bak && \
/nix/var/nix/profiles/system/bin/switch-to-configuration boot
}
prepareEnv
checkEnv
makeConf
makeSwap # smallest (512MB) droplet needs extra memory!
infect
reboot