diy shell script explanation of base image creation to run systemd-nspawn containers from btrfs subvolumes

lvbootstrap

#!/bin/sh
log=3
fence="s/.*/    &/"

echo "# How to make a new base image"
echo "for containers."
echo
echo "Create a new logical volume:"
echo
lvcreate --help 2> /dev/null | head -n $log | sed "$fence"
echo
echo
echo "Setup a filesystem on it:"
echo
mkfs.btrfs --help | head -n $log | sed "$fence"
echo
echo
echo "Mount new volume, read-write"
echo
mount --help | head -n $log | sed "$fence"
echo
echo
echo "Create a subvolume for the first _OS_ install"
echo
btrfs subvolume create --help | head -n $log | sed "$fence"
echo
echo
echo "Mount the subvolume, and bootstrap _OS_ on it"
echo
mount --help | head -n $log | sed "$fence"
debootstrap --help | head -n $log | sed "$fence"
echo
echo
echo "Unmount volume again"
echo
umount --help | head -n $log | sed "$fence"
echo
echo
echo 'Edit `/etc/fstab`, add volume e.g. __read-only__ on boot'
echo
cat /etc/fstab | head -n $log | sed "$fence"
echo
echo
echo "Spawn new container as disposable snapshot"
echo
systemd-nspawn -xb --help | head -n $log | sed "$fence"