1SYSTEMD-UDEVD.SERVICE(8)     systemd-udevd.service    SYSTEMD-UDEVD.SERVICE(8)
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NAME

6       systemd-udevd.service, systemd-udevd-control.socket, systemd-udevd-
7       kernel.socket, systemd-udevd - Device event managing daemon
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SYNOPSIS

10       systemd-udevd.service
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12       systemd-udevd-control.socket
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14       systemd-udevd-kernel.socket
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16       /usr/lib/systemd/systemd-udevd [--daemon] [--debug] [--children-max=]
17                                      [--exec-delay=] [--event-timeout=]
18                                      [--resolve-names=early|late|never]
19                                      [--version] [--help]
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DESCRIPTION

22       systemd-udevd listens to kernel uevents. For every event, systemd-udevd
23       executes matching instructions specified in udev rules. See udev(7).
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25       The behavior of the daemon can be configured using udev.conf(5), its
26       command line options, environment variables, and on the kernel command
27       line, or changed dynamically with udevadm control.
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OPTIONS

30       -d, --daemon
31           Detach and run in the background.
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33       -D, --debug
34           Print debug messages to standard error.
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36       -c, --children-max=
37           Limit the number of events executed in parallel.
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39       -e, --exec-delay=
40           Delay the execution of RUN instructions by the given number of
41           seconds. This option might be useful when debugging system crashes
42           during coldplug caused by loading non-working kernel modules.
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44       -t, --event-timeout=
45           Set the number of seconds to wait for events to finish. After this
46           time, the event will be terminated. The default is 180 seconds.
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48       -s, --timeout-signal=
49           Set the signal which systemd-udevd will send to forked off
50           processes after reaching event timeout. The setting can be
51           overridden at boot time with the kernel command line option
52           udev.timeout_signal=. Setting to SIGABRT may be helpful in order to
53           debug worker timeouts. Defaults to SIGKILL. Note that setting the
54           option on the command line overrides the setting from the
55           configuration file.
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57       -N, --resolve-names=
58           Specify when systemd-udevd should resolve names of users and
59           groups. When set to early (the default), names will be resolved
60           when the rules are parsed. When set to late, names will be resolved
61           for every event. When set to never, names will never be resolved
62           and all devices will be owned by root.
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64       -h, --help
65           Print a short help text and exit.
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67       --version
68           Print a short version string and exit.
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KERNEL COMMAND LINE

71       Parameters prefixed with "rd." will be read when systemd-udevd is used
72       in an initrd, those without will be processed both in the initrd and on
73       the host.
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75       udev.log_priority=, rd.udev.log_priority=
76           Set the log level.
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78       udev.children_max=, rd.udev.children_max=
79           Limit the number of events executed in parallel.
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81       udev.exec_delay=, rd.udev.exec_delay=
82           Delay the execution of RUN instructions by the given number of
83           seconds. This option might be useful when debugging system crashes
84           during coldplug caused by loading non-working kernel modules.
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86       udev.event_timeout=, rd.udev.event_timeout=
87           Wait for events to finish up to the given number of seconds. This
88           option might be useful if events are terminated due to kernel
89           drivers taking too long to initialize.
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91       udev.timeout_signal=, rd.udev.timeout_signal=
92           Specifies a signal that systemd-udevd will send to workers on
93           timeout. Note that kernel command line option overrides both the
94           setting in the configuration file and the one on the program
95           command line.
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97       udev.blockdev_read_only, rd.udev.blockdev_read_only
98           If specified, mark all physical block devices read-only as they
99           appear. Synthetic block devices (such as loopback block devices or
100           device mapper devices) are left as they are. This is useful to
101           guarantee that the contents of physical block devices remains
102           unmodified during runtime, for example to implement fully stateless
103           systems, for testing or for recovery situations where corrupted
104           file systems shall not be corrupted further through accidental
105           modification.
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107           A block device may be marked writable again by issuing the blockdev
108           --setrw command, see blockdev(8) for details.
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110       net.ifnames=
111           Network interfaces are renamed to give them predictable names when
112           possible. It is enabled by default; specifying 0 disables it.
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114       net.naming-scheme=
115           Network interfaces are renamed to give them predictable names when
116           possible (unless net.ifnames=0 is specified, see above). With this
117           kernel command line option it is possible to pick a specific
118           version of this algorithm and override the default chosen at
119           compilation time. Expects one of the naming scheme identifiers
120           listed in systemd.net-naming-scheme(7), or "latest" to select the
121           latest scheme known (to this particular version of
122           systemd-udevd.service).
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124           Note that selecting a specific scheme is not sufficient to fully
125           stabilize interface naming: the naming is generally derived from
126           driver attributes exposed by the kernel. As the kernel is updated,
127           previously missing attributes systemd-udevd.service is checking
128           might appear, which affects older name derivation algorithms, too.
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SEE ALSO

131       udev.conf(5), udev(7), udevadm(8)
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135systemd 246                                           SYSTEMD-UDEVD.SERVICE(8)
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