load a squashfs and run it

init

#!/bin/bash
set -x
set -o errexit
set -o nounset
set -o pipefail

function poweroff_before_panic {
  poweroff -f
}
trap poweroff_before_panic EXIT

mount -o remount,rw /
ifup -a
curl -sS -o root/ubuntu.squashfs 10.0.2.2:8080/ubuntu.squashfs

mkdir /run/roots
mount -t tmpfs -o suid,exec none /run/roots
cd /run/roots
mkdir state work image old
mount -t squashfs /root/ubuntu.squashfs image
mount -t overlay \
 -o lowerdir=image,upperdir=state,workdir=work \
 overlay /mnt

cd /mnt
mount --move /sys sys
mount --move /dev dev
mount --move /run run
mount --move /proc proc
pivot_root . run/roots/old
exec /sbin/init