SystemD¶

Increasingly, Linux distributions are adopting or planning to adopt the systemd init system. This powerful suite of software can manage many aspects of your server, from services to mounted devices and system states. ¹

Concepts¶

Unit¶

In systemd, a unit refers to any resource that the system knows how to operate on and manage. This is the primary object that the systemd tools know how to deal with. These resources are defined using configuration files called unit files. ¹

Path¶

A path unit defines a filesystem path that systmed can monitor for changes. Another unit must exist that will be be activated when certain activity is detected at the path location. Path activity is determined through inotify events.

My idea, you can use this for those services that should trigger on file uploads or backup dumps. Although I wonder if the Unit's main service knows which path was triggered? If it does, than it's easy, else you still need a "file walker".

Example¶

[Unit]
Description=Timezone Helper Service
After=network.target
StartLimitIntervalSec=0

[Service]
Type=simple
Restart=always
RestartSec=3
User=joostvdg
ExecStart=/usr/bin/timezone_helper_service

[Install]
WantedBy=multi-user.target

Resources¶

• https://www.linuxjournal.com/content/linux-filesystem-events-inotify

References¶