Our supervisor cheat sheet¶

This page collects know-how about using supervisor on a Lino server.

supervisor¶: A daemon used to monitor and control a number of processes at operating system level. Main documentation: http://supervisord.org

Overview ¶

On a production server, the equivalent of pm runserver is an asgi process running under supervisor. For each Lino site there is a separate supervisor config file. The web server (nginx) communicates with this process via a Linux socket.

Configuration files created by getlino ¶

When either web_server or appy (or both) is defined in the configuration files, getlino configure will

install the supervisor system package,
create a logrotate configuration file (/etc/logrotate.d/supervisor.conf) for /var/log/supervisor/supervisord.log,
create a libreoffice.conf file in the supervisor_dir,

and getlino startsite will install a supervisor config file for the site.

Diagnose ¶

See the status of supervisor:

$ sudo service supervisor status

Example output:

● supervisor.service - Supervisor process control system for UNIX
     Loaded: loaded (/lib/systemd/system/supervisor.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2024-11-25 10:22:11 UTC; 22s ago
       Docs: http://supervisord.org
   Main PID: 185508 (supervisord)
      Tasks: 12 (limit: 2300)
     Memory: 848.9M
        CPU: 20.056s
     CGroup: /system.slice/supervisor.service
             ├─185508 /usr/bin/python3 /usr/bin/supervisord -n -c /etc/supervisor/supervisord.conf
             ├─185509 /usr/local/lino/shared/env/pilv/bin/python /usr/local/lino/shared/env/pilv/bin/daphne -u /run/daphne/alpha_daphne0.sock --fd 0 --access-log - --proxy-headers asgi:app>
             ├─185510 /usr/local/lino/shared/env/pilv/bin/python /usr/local/lino/shared/env/pilv/bin/daphne -u /run/daphne/beta_daphne0.sock --fd 0 --access-log - --proxy-headers asgi:appl>
             ├─185511 python manage.py linod --force
             ├─185512 python manage.py linod --force
             ├─185513 /usr/lib/libreoffice/program/oosplash --accept=socket,host=127.0.0.1,port=8100;urp; --nologo --headless --nofirststartwizard
             └─185542 /usr/lib/libreoffice/program/soffice.bin --accept=socket,host=127.0.0.1,port=8100;urp; --nologo --headless --nofirststartwizard

Possible issues ¶

Main process exited¶

When the status says

Process: 184306 ExecStart=/usr/bin/supervisord -n -c /etc/supervisor/supervisord.conf (code=exited, status=1/FAILURE)

Followed later by

Main process exited, code=exited, status=1/FAILURE”.

You can manually invoke the specified command as root in order to see what happens:

$ sudo /usr/bin/supervisord -n -c /etc/supervisor/supervisord.conf

Could not create FastCGI socket¶

Possible error message during supervisord startup:

Could not create FastCGI socket tcp://127.0.0.1:8003: [Errno 98] Address already in use

This means that the process who owns this socket hasn’t been stopped for some reason. You can show a list of candidates:

$ ps aux | grep python

Or you can use netstat to get more information about which process owns a given socket:

$ sudo netstat -tulpen

Example output on a running Lino site:

Active Internet connections (only servers)
Proto  Local Address   Foreign Address State   User  Inode    PID/Program name
...
tcp    127.0.0.1:8001  0.0.0.0:*       LISTEN  0     3660773  184777/python3
tcp    127.0.0.1:8003  0.0.0.0:*       LISTEN  0     3660776  184777/python3
tcp    127.0.0.1:8100  0.0.0.0:*       LISTEN  0     1217773  58122/soffice.bin
tcp    127.0.0.1:3306  0.0.0.0:*       LISTEN  108   3534434  177680/mariadbd
tcp    127.0.0.1:6379  0.0.0.0:*       LISTEN  109   11902    560/redis-server 12
...

Our supervisor cheat sheet¶

Overview¶

Configuration files created by getlino¶

Diagnose¶

Possible issues¶