systemd-udevd.service

systemd
Developer Kay Sievers kay@vrfy.org
systemd-udevd.service 8
systemd-udevd.service systemd-udevd-control.socket systemd-udevd-kernel.socket systemd-udevd Device event managing daemon

`systemd-udevd.service`

`systemd-udevd-control.socket`

`systemd-udevd-kernel.socket`

`/lib/systemd/systemd-udevd` `--daemon` `--debug` `--children-max=` `--exec-delay=` `--resolve-names=early|late|never` `--version` `--help`

## Description

`systemd-udevd` listens to kernel uevents. For every event, systemd-udevd executes matching instructions specified in udev rules. See udev 7 .

The behavior of the running daemon can be changed with `udevadm control`.

## Options

`--daemon`

  Detach and run in the background.

`--debug`

  Print debug messages to standard error.

`--children-max=`

  Limit the number of events executed in parallel.

`--exec-delay=`

  Delay the execution of `RUN` instructions by the given number of seconds. This option might be useful when debugging system crashes during coldplug caused by loading non-working kernel modules.

`--resolve-names=`

  Specify when systemd-udevd should resolve names of users and groups. When set to `early` (the default), names will be resolved when the rules are parsed. When set to `late`, names will be resolved for every event. When set to `never`, names will never be resolved and all devices will be owned by root.

`--help`

## Environment

`$UDEV_LOG=`

  Set the logging priority.

## Kernel command line

Parameters starting with "rd." will be read when `systemd-udevd` is used in an initrd.

`udev.log-priority=`
`rd.udev.log-priority=`

  Set the logging priority.

`udev.children-max=`
`rd.udev.children-max=`

  Limit the number of events executed in parallel.

`udev.exec-delay=`
`rd.udev.exec-delay=`

  Delay the execution of `RUN` instructions by the given number of seconds. This option might be useful when debugging system crashes during coldplug caused by loading non-working kernel modules.

`net.ifnames=`

  Network interfaces are renamed to give them predictable names when possible. It is enabled by default; specifying 0 disables it.

## Configuration file

udev expects its main configuration file at `/etc/udev/udev.conf`. It consists of a set of variables allowing the user to override default udev values. All empty lines or lines beginning with '#' are ignored. The following variables can be set:

`udev_log`

  The logging priority. Valid values are the numerical syslog priorities or their textual representations: `err`, `info` and `debug`.

## See Also

udev 7 , udevadm 8