Right now Supervisor does not work with Python 3 (Supervisor version 4 will work) and it has problems stopping a Zope4 instance (needs more testing).
A systemd script could look like this:
root@xxxy:~# cat /etc/systemd/system/demo-latest.service [Unit] Description=demo-latest.plone.de After=network.target [Service] Type=simple WorkingDirectory=/home/zope/demo-latest.plone.de/ User=zope Group=zope ExecStart=/home/zope/demo-latest.plone.de/bin/instance fg [Install] WantedBy=multi-user.target
I haven't digged deep into systemd start/stop scripts, but i think i will use it more often. Are you using Supervisor? Is systemd a good replacement?