systemd-udevd.service






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
/usr/lib/systemd/systemd−udevd [−−daemon] [−−debug]
[−−children−max=] [−−exec−delay=] [−−event−timeout=]
[−−resolve−names=early|late|never] [−−version] [−−help]



     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 daemon can be configured using
udev.conf(5), its command line options, environment
variables, and on the kernel command line, or changed
dynamically with udevadm control.



     −d, −−daemon
     Detach and run in the background.

     −D, −−debug
     Print debug messages to standard error.

     −c=, −−children−max=
     Limit the number of events executed in parallel.

     −e=, −−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.

     −t=, −−event−timeout=
     Set the number of seconds to wait for events to finish.
     After this time, the event will be terminated. The
     default is 180 seconds.

     −N=, −−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









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     devices will be owned by root.

     −h, −−help
     Print a short help text and exit.

     −−version
     Print a short version string and exit.



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

     udev.log_priority=, rd.udev.log_priority=
     Set the log level.

     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.

     udev.event_timeout=, rd.udev.event_timeout=
     Wait for events to finish up to the given number of
     seconds. This option might be useful if events are
     terminated due to kernel drivers taking too long to
     initialize.

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

     net.naming−scheme=
     Network interfaces are renamed to give them predictable
     names when possible (unless net.ifnames=0 is specified,
     see above). With this kernel command line option it is
     possible to pick a specific version of this algorithm
     and override the default chosen at compilation time.
     Expects one of the naming scheme identifiers listed in
     systemd.net‐naming‐scheme(7), or "latest" to select the
     latest scheme known (to this particular version of
     systemd−udevd.service).

     Note that selecting a specific scheme is not sufficient
     to fully stabilize interface naming: the naming is
     generally derived from driver attributes exposed by the
     kernel. As the kernel is updated, previously missing
     attributes systemd−udevd.service is checking might
     appear, which affects older name derivation algorithms,
     too.









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     udev.conf(5), udev(7), udevadm(8)