Systemd service sometimes crashes on startup

Question

I try to start my Gunicorn server using systemd.

The service definition is presented below:

[Unit]
Description=Gunicorn instance to serve Flask application using gunicorn
After=network.target

[Service]
PIDFile=/home/username/application/app.pid
User=username
Group=nginx
WorkingDirectory=/home/username/application
Environment=PATH=/opt/venv/bin/
ExecStart=/opt/venv/bin/gunicorn --pid /home/username/application/app.pid --workers 3 --bind unix:socket.sock -m 007 app:app
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s TERM $MAINPID

[Install]
WantedBy=multi-user.target

The problem is that sometimes the app crashes on startup with the following messages in journalctl

gunicorn[28376]: [2019-08-22 15:01:48 +0300] [28379] [INFO] Worker exiting (pid: 28379)
gunicorn[28376]: [2019-08-22 15:01:48 +0300] [28381] [INFO] Worker exiting (pid: 28381)
gunicorn[28376]: [2019-08-22 15:01:48 +0300] [28376] [INFO] Shutting down: Master
gunicorn[28376]: [2019-08-22 15:01:48 +0300] [28376] [INFO] Reason: Worker failed to boot.
systemd[1]: urzchat-dev.service: main process exited, code=exited, status=3/NOTIMPLEMENTED
systemd[1]: urzchat-dev.service: control process exited, code=exited status=1
systemd[1]: Unit urzchat-dev.service entered failed state.
systemd[1]: urzchat-dev.service failed.

This behavior occurs about 1/3 of all starts.

Tell me, why might that be and how to fix it?

Answer 1

The Environment directive should be enclosed as a string:

Environment="PATH=/opt/venv/bin/"

Also, you may add a condition for your network being connected to the internet before start:

After=network.target network-online.target