Problem Description:

I’m encountering an issue with my Gunicorn setup while running a Django project. Specifically, I have two instances of Gunicorn running the same Django project: one using nohup and the other implemented as a systemd service. Surprisingly, the instance running with nohup works perfectly fine, while the one set up as a systemd service consistently returns a 400 error.

Background Information:

• I’m running a Django project with Gunicorn as the WSGI server.
• Each instance of Gunicorn is configured identically.
• Both instances are using the same Django project and Gunicorn configuration.

Steps Taken:

1. nohup Instance: I’m starting the nohup instance using the following command:

   nohup /home/user/project_backend/venv/bin/gunicorn --workers 5 --bind 0.0.0.0:8000    backend.wsgi:application &
   

2. It works perfectly fine!

3. Run Gunicorn as a systemd service, create or open the config file:sudo nano /etc/systemd/system/gunicorn.service

4. Following is gunicorn.service

   [Unit]
   Description=gunicorn daemon
   After=network.target
   
   [Service]
   User=user
   Group=user
   WorkingDirectory=/home/user/project_backend
   ExecStart=/home/user/project_backend/venv/bin/gunicorn --workers 5 --bind 0.0.0.0:8000
   ExecReload=/bin/kill -s HUP $MAINPID
   KillMode=mixed
   TimeoutStopSec=5
   
   [Install]
   WantedBy=multi-user.target
   

5. and thenrun sudo systemctl daemon-reload to apply the config change and sudo systemctl start gunicorn

6. Attempted to send the same HTTP request to both instances:

   • Request sent to nohup instance: success
   • Request sent to systemd service instance: failure (returned 400 error)

7. Has anyone encountered a similar issue with Gunicorn and systemd services?

8. What further steps can I take to diagnose and resolve this inconsistency between the two instances?

9. Are there any specific configuration differences between running Gunicorn with nohup and as a systemd service that could potentially cause this behavior?