systemctl complains about no installation config, but it exists
Your systemd unit doesn't have an [Install]
section. It does, however, have an [INSTALL]
section. Section names are case sensitive.
A similar warning (The unit files have no [Install] section. They are not meant to be enabled using systemctl.) can also be seen on CentOS 7 (at least) when you've already enabled the service, and the symlink already exists in /etc/systemd/system/multi-user.target.wants/. I found this out when re-running make install
from a Makefile intended for installing an app on a freshly provisioned droplet (VPS).