ungleich-tools/alpine-rebuild-initramfs.sh
2019-12-01 00:38:13 +01:00

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#!/bin/sh
set -e
set -x
MAJOR_VERSION=3.10
MINOR_VERSION=3
IMAGE=alpine-minirootfs-$MAJOR_VERSION.$MINOR_VERSION-x86_64.tar.gz
SSH_KEYS=$(cat ~/.ssh/id_rsa.pub)
RESOLVCONF=/etc/resolv.conf
working_directory=$(pwd -P)
rootfs_tmpdir=$(mktemp -d)
rootfs_url="http://dl-cdn.alpinelinux.org/alpine/v$MAJOR_VERSION/releases/x86_64/$IMAGE"
run_root () {
chroot $rootfs_tmpdir /usr/bin/env \
PATH=/bin:/sbin \
/bin/sh -c "$*"
}
if [ "$(whoami)" != 'root' ]; then
echo "This script must be run as root." >&2
exit 1
fi
# Download, extract inital rootfs.
curl "$rootfs_url" -o "$working_directory/$IMAGE"
tar xf $IMAGE -C $rootfs_tmpdir
# Add SSH keys
run_root mkdir -p root/.ssh
echo $SSH_KEYS > $rootfs_tmpdir/root/.ssh/authorized_keys
run_root chmod 0600 root/.ssh/authorized_keys
run_root chmod 0700 root/.ssh
# Import local resolv.conf.
cat "$RESOLVCONF" > $rootfs_tmpdir/etc/resolv.conf
# Make sure init is found by the kernel.
run_root ln -s /sbin/init /init
cat > "$rootfs_tmpdir/etc/network/interfaces" <<EOF
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet6 manual
pre-up modprobe ipv6 && sysctl -w net.ipv6.conf.eth0.accept_ra=1
post-up ip addr show dev eth0 | grep inet6 >> /etc/issue
EOF
cat > "$rootfs_tmpdir/etc/hostname" <<EOF
alpine-unconfigured
EOF
# Layer atop base rootfs.
run_root apk update
run_root apk upgrade
run_root apk add openssh linux-vanilla openrc udev
run_root rc-update add udev
run_root rc-update add sshd
run_root rc-update add networking
run_root rc-update add hostname
# FIXME: add / install rdnssd / ndisc6 / start it on boot
# ndisc6 is only @testing
# Generate iniramfs image
(cd $rootfs_tmpdir; find . | cpio -H newc -o | gzip -9 > "$working_directory/alpine-initramfs.gz")
cp "$rootfs_tmpdir/boot/vmlinuz-vanilla" "$working_directory/alpine-kernel"
# Cleanup.
rm -r "$rootfs_tmpdir"
# Upload to netboot server. - needs to be done outside sudo
echo "Use alpine-initramfs.gz alpine-kernel from $working_directory"!