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.TH "SYSTEMD\-UDEVD\&.SERVICE" "8" "" "systemd 241" "systemd-udevd.service"
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.SH "NAME"
systemd-udevd.service, systemd-udevd-control.socket, systemd-udevd-kernel.socket, systemd-udevd \- Device event managing daemon
.SH "SYNOPSIS"
.PP
systemd\-udevd\&.service
.PP
systemd\-udevd\-control\&.socket
.PP
systemd\-udevd\-kernel\&.socket
.HP \w'\fB/lib/systemd/systemd\-udevd\fR\ 'u
\fB/lib/systemd/systemd\-udevd\fR [\fB\-\-daemon\fR] [\fB\-\-debug\fR] [\fB\-\-children\-max=\fR] [\fB\-\-exec\-delay=\fR] [\fB\-\-event\-timeout=\fR] [\fB\-\-resolve\-names=early|late|never\fR] [\fB\-\-version\fR] [\fB\-\-help\fR]
.SH "DESCRIPTION"
.PP
\fBsystemd\-udevd\fR
listens to kernel uevents\&. For every event, systemd\-udevd executes matching instructions specified in udev rules\&. See
\fBudev\fR(7)\&.
.PP
The behavior of the daemon can be configured using
\fBudev.conf\fR(5), its command line options, environment variables, and on the kernel command line, or changed dynamically with
\fBudevadm control\fR\&.
.SH "OPTIONS"
.PP
\fB\-d\fR, \fB\-\-daemon\fR
.RS 4
Detach and run in the background\&.
.RE
.PP
\fB\-D\fR, \fB\-\-debug\fR
.RS 4
Print debug messages to standard error\&.
.RE
.PP
\fB\-c=\fR, \fB\-\-children\-max=\fR
.RS 4
Limit the number of events executed in parallel\&.
.RE
.PP
\fB\-e=\fR, \fB\-\-exec\-delay=\fR
.RS 4
Delay the execution of
\fIRUN\fR
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\&.
.RE
.PP
\fB\-t=\fR, \fB\-\-event\-timeout=\fR
.RS 4
Set the number of seconds to wait for events to finish\&. After this time, the event will be terminated\&. The default is 180 seconds\&.
.RE
.PP
\fB\-N=\fR, \fB\-\-resolve\-names=\fR
.RS 4
Specify when systemd\-udevd should resolve names of users and groups\&. When set to
\fBearly\fR
(the default), names will be resolved when the rules are parsed\&. When set to
\fBlate\fR, names will be resolved for every event\&. When set to
\fBnever\fR, names will never be resolved and all devices will be owned by root\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
Print a short help text and exit\&.
.RE
.PP
\fB\-\-version\fR
.RS 4
Print a short version string and exit\&.
.RE
.SH "KERNEL COMMAND LINE"
.PP
Parameters starting with "rd\&." will be read when
\fBsystemd\-udevd\fR
is used in an initrd\&.
.PP
\fIudev\&.log_priority=\fR, \fIrd\&.udev\&.log_priority=\fR
.RS 4
Set the log level\&.
.RE
.PP
\fIudev\&.children_max=\fR, \fIrd\&.udev\&.children_max=\fR
.RS 4
Limit the number of events executed in parallel\&.
.RE
.PP
\fIudev\&.exec_delay=\fR, \fIrd\&.udev\&.exec_delay=\fR
.RS 4
Delay the execution of
\fIRUN\fR
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\&.
.RE
.PP
\fIudev\&.event_timeout=\fR, \fIrd\&.udev\&.event_timeout=\fR
.RS 4
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\&.
.RE
.PP
\fInet\&.ifnames=\fR
.RS 4
Network interfaces are renamed to give them predictable names when possible\&. It is enabled by default; specifying 0 disables it\&.
.RE
.PP
\fInet\&.naming\-scheme=\fR
.RS 4
Network interfaces are renamed to give them predictable names when possible (unless
\fInet\&.ifnames=0\fR
is specified, see above)\&. The names are derived from various device metadata fields\&. Newer versions of
systemd\-udevd\&.service
take more of these fields into account, improving (and thus possibly changing) the names used for the same devices\&. With this kernel command line option it is possible to pick a specific version of this algorithm\&. It expects a naming scheme identifier as argument\&. Currently the following identifiers are known:
"v238",
"v239",
"v240"
which each implement the naming scheme that was the default in the indicated systemd version\&. In addition,
"latest"
may be used to designate the latest scheme known (to this particular version of
systemd\-udevd\&.service)\&.
.sp
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\&.
.RE
.SH "SEE ALSO"
.PP
\fBudev.conf\fR(5),
\fBudev\fR(7),
\fBudevadm\fR(8)