Pubapps Systemd Use

back to Web_Application_Hosting

Introduction

If one or more of your web applications hosted on pubapps infrastructure are architected to run on the webserver you need to have two copies of the app running on every pubweb[1,2] server to account for the HA (High Availability) configuration of the pubapps infrastructure where a secondary pubweb webserver will take over if there is an issue with the main webserver. To make sure your web applications are running after an HA failover or start when a server in pubapps infrastructure is restarted we encourage you to use a systemd script, which can automate the start/stop/restart process. This help article should help you create and use such a script.

Configuration

Systemd has two modes of operation - system-wide, which requires the service scripts to be in a system location and operated by root and a user mode. You will be using the user mode.

• Create a user systemd directory under your /pubapps/PROJECT/ $HOME directory in pubapps

mkdir -p .config/systemd/user/

• Add a service script for the application, e.g. ~/.config/systemd/user/projprod.service or projdev.service

Script

Example systemd script

[Unit]
Description=MyProject (Production)
After=network.target

[Service]
Type=simple

WorkingDirectory=/pubapps/myinstance/myproject/prod/
ExecStart=/pubapps/myinstance/myproject/prod/conda/bin/python3 run/runserver.py
TimeoutSec=30
RestartSec=15s
Restart=always

[Install]
WantedBy=multi-user.target

Use

• Enable user linger mode to avoid having your application be shut down when you log out:

loginctl enable-linger PROJECTUSER

• Manage the application with
  • Initial load of the configuration to enable the service

systemctl --user enable projprod

• • Reload configuration (after every change of the systemd service script)

systemctl --user daemon-reload

• • Start service

systemctl --user start projprod

• • Stop service

systemctl --user stop projprod

• • Restart service

systemctl --user restart projprod

• • Check if the service is running

systemctl --user status projprod

• Start the application on pubweb[1,2] servers.

For additional information search web for 'systemd user mode'. E.g. https://wiki.archlinux.org/title/Systemd/User