1SYSTEMD-UDEVD.SERVICE(8) systemd-udevd.service SYSTEMD-UDEVD.SERVICE(8)
2
6 systemd-udevd.service, systemd-udevd-control.socket, systemd-udevd-
7 kernel.socket, systemd-udevd - Device event managing daemon
8
10 systemd-udevd.service
11 systemd-udevd-control.socket
13 systemd-udevd-kernel.socket
15 /usr/lib/systemd/systemd-udevd [--daemon] [--debug] [--children-max=]
17 [--exec-delay=] [--event-timeout=]
18 [--resolve-names=early|late|never]
19 [--version] [--help]
20
22 systemd-udevd listens to kernel uevents. For every event, systemd-udevd
23 executes matching instructions specified in udev rules. See udev(7).
24 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.
28
30 -d, --daemon
31 Detach and run in the background.
32 -D, --debug
34 Print debug messages to standard error.
35 -c, --children-max=
37 Limit the number of events executed in parallel.
38 -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.
43 -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.
47 -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.
56 -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.
63 -h, --help
65 Print a short help text and exit.
66 --version
68 Print a short version string and exit.
69
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.
74 udev.log_priority=, rd.udev.log_priority=
76 Set the log level.
77 udev.children_max=, rd.udev.children_max=
79 Limit the number of events executed in parallel.
80 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.
85 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.
90 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.
96 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.
106 A block device may be marked writable again by issuing the blockdev
108 --setrw command, see blockdev(8) for details.
109 net.ifnames=
111 Network interfaces are renamed to give them predictable names when
112 possible. It is enabled by default; specifying 0 disables it.
113 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).
123 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.
129
131 udev.conf(5), udev(7), udevadm(8)
132systemd 246 SYSTEMD-UDEVD.SERVICE(8)