unattended.sh for Raspberry Pi Zero 2 W, camera support, Ansible deploy target

[strophy]

This script was developed to help install Alpine 3.22 on headless Raspberry Pi Zero 2 W boards connecting by Wifi. The SD card is flashed with alpine-rpi-3.22.2-aarch64.img and then populated with the following files:

• headless.apkovl.tar.gz (from this repo)
• authorized_keys (my ssh pubkey)
• unattended.sh (this script)
• wpa_supplicant.conf (wifi connection details)

It then installs itself in sys mode to the SD card, creates two users, sets up Python so the host can be managed by Ansible, sets up camera and gpu devices and persists the network configuration after a reboot.

#!/bin/sh

# Uncomment to enable stdout and errors redirection to console (service won't show messages)
exec 1>/dev/console 2>&1

# shellcheck disable=SC2142  # known special case
alias _logger='logger -st "${0##*/}"'
_logger "Setting-up minimal environment"

ntpd -d -q -n -p pool.ntp.org
_logger "Time synchronized"

SSH_KEY="$(cat /media/mmcblk0/authorized_keys)"

apk add wpa_supplicant
cp /media/mmcblk0/wpa_supplicant.conf /etc/wpa_supplicant/wpa_supplicant.conf
rc-update add wpa_supplicant boot
_logger "Wifi configured"

cat <<-EOF > /tmp/ANSWERFILE
	KEYMAPOPTS="us us"
	HOSTNAMEOPTS="$(hostname)"
	DEVDOPTS=udev
	INTERFACESOPTS="auto lo
	iface lo inet loopback
	
	auto wlan0
	iface wlan0 inet dhcp
	"
	DNSOPTS="none"
	TIMEZONEOPTS="CET"
	PROXYOPTS=none
	APKREPOSOPTS="-1 -c"
	USEROPTS="-a -u pi"
	USERSSHKEY="${SSH_KEY}"
	SSHDOPTS=openssh
	ROOTSSHKEY="${SSH_KEY}"
	NTPOPTS="busybox"
	DISKOPTS=none
	EOF

SSH_CONNECTION="FAKE" setup-alpine -ef /tmp/ANSWERFILE

echo "root:password" | chpasswd
echo "pi:password" | chpasswd
_logger "Initial passwords set"

# Pass disk device via stdin since boot media needs special handling
_logger "Starting disk installation"
printf 'y\nmmcblk0\ny\n' | setup-disk -m sys

# Mount the newly installed system and install Python via chroot
# Needs to be done here because there is not enough space before setup-disk runs
_logger "Mounting new system for post-installation"
mount /dev/mmcblk0p2 /mnt
mount /dev/mmcblk0p1 /mnt/boot
mount --bind /dev /mnt/dev
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys

_logger "Configuring GPU memory and hardware acceleration"
cat > /mnt/boot/usercfg.txt <<-EOF
	gpu_mem=128
	start_x=0
	dtoverlay=vc4-kms-v3d
	dtoverlay=imx219
	EOF

_logger "Configuring repositories"
cat > /mnt/etc/apk/repositories <<-EOF
	https://dl-cdn.alpinelinux.org/alpine/v3.22/main
	https://dl-cdn.alpinelinux.org/alpine/v3.22/community
	https://dl-cdn.alpinelinux.org/alpine/edge/main
	https://dl-cdn.alpinelinux.org/alpine/edge/community
	https://dl-cdn.alpinelinux.org/alpine/edge/testing
	EOF

_logger "Installing useful apps in disk-based system"
chroot /mnt /bin/sh -c 'apk add btop nano python3'

_logger "Cleaning up mounts"
umount /mnt/sys
umount /mnt/proc
umount /mnt/dev
umount /mnt/boot
umount /mnt

_logger "Finished unattended script - rebooting system"
reboot

[macmpi]

cat > /mnt/boot/usercfg.txt <<-EOF
gpu_mem=128
start_x=0

note gpu_mem and start_x statements will only operate if in root config.txt 😉
(unfortunately they may be wiped there after kernel or bootloader updates...may be fixed soon)