build_container.sh

#!/bin/sh
set -xe

# generic system setup
apt install -y debootstrap systemd-container
systemd-machine-id-setup
systemctl enable machines.target
#echo 'kernel.unprivileged_userns_clone=1' > /etc/sysctl.d/nspawn.conf
#echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.d/nspawn.conf
systemctl restart systemd-sysctl.service
systemctl enable systemd-networkd
cp container/80-container-ve.network /etc/systemd/network/ # override default conf to remove LinkLocalAddressing which conflicts with GCP internal DNS address #sad
systemctl restart systemd-networkd

# params
name=test
container=/var/lib/machines/$name/

# destroy existing setup
systemctl disable systemd-nspawn@$name.service
systemctl stop systemd-nspawn@$name.service
rm -f /etc/systemd/nspawn/$name.nspawn
rm -rf $container

# create new setup
debootstrap --include=systemd-container,ca-certificates buster $container
echo 'deb http://security.debian.org/ buster/updates main contrib non-free' >> $container/etc/apt/sources.list
echo 'deb http://deb.debian.org/debian buster-updates main contrib non-free' >> $container/etc/apt/sources.list
#echo 'deb [trusted=yes] file:///repo ./' >> $container/etc/apt/sources.list
#cp -rv repo $container/
systemd-nspawn -D $container -E DEBIAN_FRONTEND=noninteractive apt update -y
systemd-nspawn -D $container -E DEBIAN_FRONTEND=noninteractive apt upgrade -y
systemd-nspawn -D $container -E DEBIAN_FRONTEND=noninteractive apt dist-upgrade -y

systemd-nspawn -D $container systemctl enable systemd-networkd.service
systemd-nspawn -D $container systemctl enable systemd-resolved.service

ln -sf /run/systemd/resolve/stub-resolv.conf $container/etc/resolv.conf

mkdir -p /etc/systemd/nspawn/
#echo "[Network]" > /etc/systemd/nspawn/$name.nspawn
#echo "Zone=$name" >> /etc/systemd/nspawn/$name.nspawn
cp container/80-container-host0.network $container/etc/systemd/network/ # override default conf to remove LinkLocalAddressing which conflicts with GCP internal DNS address #sad
systemctl enable systemd-nspawn@$name.service
systemctl start systemd-nspawn@$name.service