Pubapps Systemd Use

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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
  • 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

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