EDIT: Works for root, sudo is the problem. Read below.
I have a directory with my own libraries, e.g. my Python libraries are located at /home/name/lib/py
Follow configuration helps me to run multiple python services in dedicated VENVs on one Centos host
/etc/sysconfig/my-appEnvironmentFile option in service config see code below:
-bash-4.2$ sudo vi /etc/sysconfig/my-app
PATH=/usr/local/my-app/env/bin:$PATH
LD_LIBRARY_PATH=/usr/local/my-app/env/lib:$LD_LIBRARY_PATH
-bash-4.2$ sudo vi /etc/systemd/system/my-app.service
[Unit]
Description=my-app daemon
After=network.target
[Service]
EnvironmentFile=/etc/sysconfig/my_app
User=app_user
Group=app_user
Type=simple
ExecStart=/usr/local/my-app/env/bin/python /usr/local/my-app/main.py
Restart=on-failure
RestartSec=5s
PrivateTmp=true
[Install]
WantedBy=multi-user.target