install

apt install systemd-container

setup old distribution

root@saturn4:~# cat /saturn/etc/os-release
PRETTY_NAME="Debian GNU/Linux 4 (etch)"
NAME="Debian GNU/Linux"
VERSION_ID="4"
VERSION="4 (etch)"
VERSION_CODENAME=etch
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"