systemd-machine-tag@.service

systemd

Add a machine tag to the host

systemd-machine-tag@.service

Description

systemd-machine-tag@TAG.service is a service template that adds the machine tag <TAG> (taken from the instance name) to the host's list of machine tags. Whenever an instance of this template is pulled in, the corresponding tag is added; the operation is idempotent, so pulling it in repeatedly has no further effect.

The primary use of this template is automatic, hardware-driven tagging: the SYSTEMD_MACHINE_TAG udev property, when set on a device, causes the matching instance of this template to be pulled in (via SYSTEMD_WANTS=), so that plugging in or detecting a specific device automatically tags the host. See systemd.device(5) for details on the SYSTEMD_WANTS= mechanism.

Machine tags may be inspected and edited with the tags verb of hostnamectl(1), and are stored in the TAGS= field of machine-info(5). Each tag must be 1…255 characters long and consist only of ASCII alphanumeric characters, - and ..