../_images/openl2m_logo.png

Gunicorn Installation

OpenL2M is developed and tested running as an application under the gunicorn WSGI service. This basically runs the OpenL2m Python code as a service process with a WSGI interface. The Nginx web server talks in the backend to this WSGI interface to render client http requests. Gunicorn is started as a service from systemd. (Note that Apache web server should work fine, but is left as an exercise to the reader.)

The gunicorn program was installed during the OpenL2M installation (in the Python Virtual environment). You need to copy the Gunicorn configuration into the “root” openl2m installation path as gunicorn_config.py (e.g. /opt/openl2m/gunicorn_config.py per our example installation).

cp /opt/openl2m/scripts/gunicorn_config.py /opt/openl2m/gunicorn_config.py

Modify this file as needed for your environment. Note the following:

  • If you change the service port from 8001, you will also need to change the corresponding nginx configuration (see later on)!

  • The number of workers is related to how many users your site will service at the same time. If this is large, increase the 3 to something higher, and restart the service (see below)

  • The timeout is increased from the default 30 seconds, to 150. This is to allow large switch stacks to be polled without causing a process timeout. You may need to adjust this timeout to suit your environment.

systemd configuration

We will install Gunicorn as a service under systemd. The systemd service definition is in the file ‘openl2m.service’.

Copy the file openl2m.service to the /etc/systemd/system directory:

sudo cp /opt/openl2m/scripts/openl2m.service /etc/systemd/system

Now activate this service:

sudo systemctl daemon-reload
sudo systemctl start openl2m
sudo systemctl enable openl2m

And verify:

sudo systemctl status openl2m

This should return several lines, indicating the service is running. It should end with something similar to this:

CGroup: /system.slice/openl2m.service
        ├─1008503 /opt/openl2m/venv/bin/python3 /opt/openl2m/venv/bin/gunicorn --pid /var/tmp/openl2m.pid --pythonpath >
        ├─1008523 /opt/openl2m/venv/bin/python3 /opt/openl2m/venv/bin/gunicorn --pid /var/tmp/openl2m.pid --pythonpath >
        ├─1008524 /opt/openl2m/venv/bin/python3 /opt/openl2m/venv/bin/gunicorn --pid /var/tmp/openl2m.pid --pythonpath >
        └─1008525 /opt/openl2m/venv/bin/python3 /opt/openl2m/venv/bin/gunicorn --pid /var/tmp/openl2m.pid --pythonpath >

Oct 25 23:37:56 openl2m-server systemd[1]: Started OpenL2M - Open Layer 2 Switch Management WSGI Service.

If all is well, you are now ready to install the webserver.