images/alpine-uncloud-image.sh

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#!/bin/sh
# This script generates Alpine images for Uncloud.
#
# Test image locally (without network) with:
# qemu-system-x86_64 -enable-kvm -m 1G -drive file=$IMAGE,format=qcow2
set -e
set -x
# XXX: Handle command-line arguments?
RELEASE=v3.11
ARCH=x86_64
IMAGE_PATH=alpine-uncloud-$RELEASE-$(date -I).img.qcow2
IMAGE_SIZE=10G
NBD_DEVICE=/dev/nbd1
APK_MIRROR=http://dl-2.alpinelinux.org/alpine/ # Mind the trailing /
cleanup() {
# The order here is important.
umount /mnt/dev/pts 2>/dev/null || true
umount /mnt/dev/shm 2>/dev/null || true
umount /mnt/dev 2>/dev/null || true
umount /mnt/proc 2>/dev/null || true
umount /mnt/run 2>/dev/null || true
umount /mnt/sys 2>/dev/null || true
umount /mnt/boot 2>/dev/null || true
umount /mnt 2>/dev/null || true
qemu-nbd --disconnect "$NBD_DEVICE" || true
}
run_root() {
chroot /mnt /usr/bin/env \
PATH=/sbin:/usr/sbin:/bin:/usr/bin \
sh -c "$*"
}
if [ "$(whoami)" != 'root' ]; then
echo "This script must be run as root." >&2
exit 1
fi
if [ $(lsb_release --short --id) != "Alpine" ]; then
echo "WARNING: this script has been designed to run on an Alpine system." >&2
echo "WARNING: Not running Alpine. Giving you 5 seconds to abort." >&2
sleep 5
fi
# Create base QCOW2 image.
qemu-img create -f qcow2 "$IMAGE_PATH" "$IMAGE_SIZE"
modprobe nbd max_part=16
qemu-nbd --connect="$NBD_DEVICE" "$IMAGE_PATH"
# Wait for qemu-nbd to settle.
sleep 1
# Don't forget to cleanup, even if the script crash.
trap cleanup EXIT
# Create partition table, format partitions.
sfdisk --no-reread "$NBD_DEVICE" <<EOF
1M,500M,L,*
,,L
EOF
mkfs.ext4 "${NBD_DEVICE}p1"
mkfs.ext4 "${NBD_DEVICE}p2"
# Mount partitions, install base OS.
mount "${NBD_DEVICE}p2" /mnt
mkdir /mnt/boot
mount "${NBD_DEVICE}p1" /mnt/boot
# TODO: Remove bash
apk add -U -X $APK_MIRROR$RELEASE/main/ \
--allow-untrusted \
--arch="$ARCH" \
--root=/mnt \
--initdb \
alpine-base alpine-conf openssh sudo syslinux tzdata gnupg bash
mount --bind /dev /mnt/dev
mount --bind /dev/pts /mnt/dev/pts
mount --bind /dev/shm /mnt/dev/shm
mount --bind /proc /mnt/proc
mount --bind /run /mnt/run
mount --bind /sys /mnt/sys
# Required to resolve package mirror in chroot.
cp /etc/resolv.conf /mnt/etc/resolv.conf
# Initialize /etc/hosts.
cat > /mnt/etc/hosts << EOF
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
EOF
# Accept router advertisements for SLAAC.
run_root sysctl -w net.ipv6.conf.all.accept_ra=1
# Configure package sources and update package index.
run_root setup-timezone -z UTC
if [ "$RELEASE" = "edge" ]
then
cat >/mnt/etc/apk/repositories <<EOF
$APK_MIRROR$RELEASE/main
$APK_MIRROR$RELEASE/community
$APK_MIRROR$RELEASE/testing
EOF
else
cat >/mnt/etc/apk/repositories <<EOF
$APK_MIRROR$RELEASE/main
$APK_MIRROR$RELEASE/community
EOF
fi
# Update package index.
run_root apk update
# Install RDNSSD for DNS discovery from router advertisement.
run_root apk add ndisc6
# Initialize base services.
for i in ntpd sshd crond rdnssd; do
run_root rc-update add $i default
done
for i in hwclock modules sysctl hostname bootmisc networking syslog swap urandom; do
run_root rc-update add $i boot
done
for i in mount-ro killprocs savecache; do
run_root rc-update add $i shutdown
done
# Set hostname.
run_root setup-hostname -n alpine
# Install kernel and bootloader.
dd if=/usr/share/syslinux/mbr.bin of=/dev/nbd0 bs=1 count=440
extlinux -i /mnt/boot
cat >/mnt/boot/extlinux.conf <<EOF
DEFAULT linux
LABEL linux
LINUX vmlinuz-$(echo "$linux" | cut -d- -f2-)
INITRD initramfs-$(echo "$linux" | cut -d- -f2-)
APPEND root=/dev/vda3 rw modules=sd-mod,usb-storage,ext4 quiet rootfstype=ext4
EOF
run_root apk add linux-virt
# Generate fstab file.
boot_uuid=$(blkid --match-tag UUID --output value "${NBD_DEVICE}p1")
root_uuid=$(blkid --match-tag UUID --output value "${NBD_DEVICE}p2")
cat >>/mnt/etc/fstab <<EOF
UUID=$boot_uuid /boot ext4 rw,relatime,data=ordered 0 2
UUID=$root_uuid / ext4 rw,relatime,data=ordered 0 1
EOF
# FIXME: add fnux's SSH key for testing purposes.
mkdir -p /mnt/root/.ssh
curl https://key.wf/fnux > /mnt/root/.ssh/authorized_keys
# Make sure everything is written to disk before exiting.
sync