nixos-images/nix/kexec-installer/kexec-run.sh

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#!/bin/sh
set -ex
# provided by nix
init="@init@"
kernelParams="@kernelParams@"
SCRIPT_DIR=$(dirname "$(readlink -f "$0")")
INITRD_TMP=$(TMPDIR=$SCRIPT_DIR mktemp -d)
cd "$INITRD_TMP"
cleanup() {
rm -rf "$INITRD_TMP"
}
trap cleanup EXIT
mkdir -p ssh
extractPubKeys() {
home="$1"
for file in .ssh/authorized_keys .ssh/authorized_keys2; do
key="$home/$file"
if test -e "$key"; then
# workaround for debian shenanigans
grep -o '\(\(ssh\|ecdsa\|sk\)-[^ ]* .*\)' "$key" >> ssh/authorized_keys || true
fi
done
}
extractPubKeys /root
if test -n "${SUDO_USER-}"; then
sudo_home=$(sh -c "echo ~$SUDO_USER")
extractPubKeys "$sudo_home"
fi
# Typically for NixOS
if test -e /etc/ssh/authorized_keys.d/root; then
cat /etc/ssh/authorized_keys.d/root >> ssh/authorized_keys
fi
if test -n "${SUDO_USER-}" && test -e "/etc/ssh/authorized_keys.d/$SUDO_USER"; then
cat "/etc/ssh/authorized_keys.d/$SUDO_USER" >> ssh/authorized_keys
fi
for p in /etc/ssh/ssh_host_*; do
test -e "$p" || continue
cp -a "$p" ssh
done
# save the networking config for later use
"$SCRIPT_DIR/ip" --json addr > addrs.json
"$SCRIPT_DIR/ip" -4 --json route > routes-v4.json
"$SCRIPT_DIR/ip" -6 --json route > routes-v6.json
find . | cpio -o -H newc | gzip -9 >> "$SCRIPT_DIR/initrd"
if ! "$SCRIPT_DIR/kexec" --load "$SCRIPT_DIR/bzImage" \
--kexec-syscall-auto \
--initrd="$SCRIPT_DIR/initrd" --no-checks \
--command-line "init=$init $kernelParams"; then
echo "kexec failed, dumping dmesg"
dmesg | tail -n 100
exit 1
fi
# Disconnect our background kexec from the terminal
echo "machine will boot into nixos in 6s..."
if test -e /dev/kmsg; then
# this makes logging visible in `dmesg`, or the system console or tools like journald
exec > /dev/kmsg 2>&1
else
exec > /dev/null 2>&1
fi
# We will kexec in background so we can cleanly finish the script before the hosts go down.
# This makes integration with tools like terraform easier.
nohup sh -c "sleep 6 && '$SCRIPT_DIR/kexec' -e" &