1 <?xml version='
1.0'
?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
6 <refentry id=
"kernel-command-line" xmlns:
xi=
"http://www.w3.org/2001/XInclude">
9 <title>kernel-command-line
</title>
10 <productname>systemd
</productname>
14 <refentrytitle>kernel-command-line
</refentrytitle>
15 <manvolnum>7</manvolnum>
19 <refname>kernel-command-line
</refname>
20 <refpurpose>Kernel command line parameters
</refpurpose>
24 <para><filename>/proc/cmdline
</filename></para>
28 <title>Description
</title>
30 <para>The kernel, the programs running in the initrd and in the host system may be configured at boot via
31 kernel command line arguments. In addition, various systemd tools look at the EFI variable
32 <literal>SystemdOptions
</literal> (if available). Both sources are combined, but the kernel command line
33 has higher priority. Please note that
<emphasis>the EFI variable is only used by systemd tools, and is
34 ignored by the kernel and other user space tools
</emphasis>, so it is not a replacement for the kernel
37 <para>For command line parameters understood by the kernel, please
39 <ulink url=
"https://docs.kernel.org/admin-guide/kernel-parameters.html"><filename>kernel-parameters.html
</filename></ulink>
41 <citerefentry project='man-pages'
><refentrytitle>bootparam
</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
</para>
43 <para>For command line parameters understood by the initrd, see
44 <citerefentry project='man-pages'
><refentrytitle>dracut.cmdline
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
45 or the documentation of the specific initrd implementation of your
50 <title>Core OS Command Line Arguments
</title>
52 <variablelist class='kernel-commandline-options'
>
54 <term><varname>systemd.unit=
</varname></term>
55 <term><varname>rd.systemd.unit=
</varname></term>
56 <term><varname>systemd.dump_core
</varname></term>
57 <term><varname>systemd.crash_chvt
</varname></term>
58 <term><varname>systemd.crash_shell
</varname></term>
59 <term><varname>systemd.crash_reboot
</varname></term>
60 <term><varname>systemd.confirm_spawn
</varname></term>
61 <term><varname>systemd.service_watchdogs
</varname></term>
62 <term><varname>systemd.show_status
</varname></term>
63 <term><varname>systemd.status_unit_format=
</varname></term>
64 <term><varname>systemd.log_target=
</varname></term>
65 <term><varname>systemd.log_level=
</varname></term>
66 <term><varname>systemd.log_location=
</varname></term>
67 <term><varname>systemd.log_color
</varname></term>
68 <term><varname>systemd.log_ratelimit_kmsg
</varname></term>
69 <term><varname>systemd.default_standard_output=
</varname></term>
70 <term><varname>systemd.default_standard_error=
</varname></term>
71 <term><varname>systemd.setenv=
</varname></term>
72 <term><varname>systemd.machine_id=
</varname></term>
73 <term><varname>systemd.set_credential=
</varname></term>
74 <term><varname>systemd.set_credential_binary=
</varname></term>
75 <term><varname>systemd.import_credentials=
</varname></term>
76 <term><varname>systemd.reload_limit_interval_sec=
</varname></term>
77 <term><varname>systemd.reload_limit_burst=
</varname></term>
79 <para>Parameters understood by the system and service
80 manager to control system behavior. For details, see
81 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
83 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
88 <term><varname>systemd.mask=
</varname></term>
89 <term><varname>systemd.wants=
</varname></term>
90 <term><varname>systemd.debug_shell
</varname></term>
92 <para>Additional parameters understood by
93 <citerefentry><refentrytitle>systemd-debug-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
94 to mask or start specific units at boot, or invoke a debug
97 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
102 <term><varname>systemd.run=
</varname></term>
103 <term><varname>systemd.run_success_action=
</varname></term>
104 <term><varname>systemd.run_failure_action=
</varname></term>
106 <para>Additional parameters understood by
107 <citerefentry><refentrytitle>systemd-run-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>, to
108 run a command line specified on the kernel command line as system service after booting up.
</para>
110 <xi:include href=
"version-info.xml" xpointer=
"v240"/>
115 <term><varname>systemd.early_core_pattern=
</varname></term>
117 <para>During early boot, the generation of core dump files is disabled until a core dump handler (if any)
118 takes over. This parameter allows specifying an absolute path where core dump files should be stored until
119 a handler is installed. The path should be absolute and may contain specifiers, see
120 <citerefentry project='man-pages'
><refentrytitle>core
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.
</para>
122 <xi:include href=
"version-info.xml" xpointer=
"v240"/>
127 <term><varname>systemd.restore_state=
</varname></term>
129 <para>This parameter is understood by several system tools
130 to control whether or not they should restore system state
131 from the previous boot. For details, see
132 <citerefentry><refentrytitle>systemd-backlight@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
134 <citerefentry><refentrytitle>systemd-rfkill.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
137 <xi:include href=
"version-info.xml" xpointer=
"v209"/>
142 <term><varname>systemd.volatile=
</varname></term>
144 <para>This parameter controls whether the system shall boot up in volatile mode. Takes a boolean argument, or
145 the special value
<literal>state
</literal>. If false (the default), normal boot mode is selected, the root
146 directory and
<filename>/var/
</filename> are mounted as specified on the kernel command line or
147 <filename>/etc/fstab
</filename>, or otherwise configured. If true, full state-less boot mode is selected. In
148 this case the root directory is mounted as volatile memory file system (
<literal>tmpfs
</literal>), and only
149 <filename>/usr/
</filename> is mounted from the file system configured as root device, in read-only mode. This
150 enables fully state-less boots were the vendor-supplied OS is used as shipped, with only default
151 configuration and no stored state in effect, as
<filename>/etc/
</filename> and
<filename>/var/
</filename> (as
152 well as all other resources shipped in the root file system) are reset at boot and lost on shutdown. If this
153 setting is set to
<literal>state
</literal> the root file system is mounted read-only, however
154 <filename>/var/
</filename> is mounted as a volatile memory file system (
<literal>tmpfs
</literal>), so that the
155 system boots up with the normal configuration applied, but all state reset at boot and lost at shutdown. If
156 this setting is set to
<literal>overlay
</literal> the root file system is set up as
157 <literal>overlayfs
</literal> mount combining the read-only root directory with a writable
158 <literal>tmpfs
</literal>, so that no modifications are made to disk, but the file system may be modified
159 nonetheless with all changes being lost at reboot. For details, see
160 <citerefentry><refentrytitle>systemd-volatile-root.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
162 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
164 <xi:include href=
"version-info.xml" xpointer=
"v233"/>
169 <term><varname>quiet
</varname></term>
171 <para>Parameter understood by both the kernel and the system
172 and service manager to control console log verbosity. For
174 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
176 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
181 <term><varname>debug
</varname></term>
183 <para>Parameter understood by both the kernel and the system
184 and service manager to control console log verbosity. For
186 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
188 <xi:include href=
"version-info.xml" xpointer=
"v205"/>
193 <term><varname>-b
</varname></term>
194 <term><varname>rd.emergency
</varname></term>
195 <term><varname>emergency
</varname></term>
196 <term><varname>rd.rescue
</varname></term>
197 <term><varname>rescue
</varname></term>
198 <term><varname>single
</varname></term>
199 <term><varname>s
</varname></term>
200 <term><varname>S
</varname></term>
201 <term><varname>1</varname></term>
202 <term><varname>2</varname></term>
203 <term><varname>3</varname></term>
204 <term><varname>4</varname></term>
205 <term><varname>5</varname></term>
207 <para>Parameters understood by the system and service
208 manager, as compatibility and convenience options. For details, see
209 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
211 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
216 <term><varname>locale.LANG=
</varname></term>
217 <term><varname>locale.LANGUAGE=
</varname></term>
218 <term><varname>locale.LC_CTYPE=
</varname></term>
219 <term><varname>locale.LC_NUMERIC=
</varname></term>
220 <term><varname>locale.LC_TIME=
</varname></term>
221 <term><varname>locale.LC_COLLATE=
</varname></term>
222 <term><varname>locale.LC_MONETARY=
</varname></term>
223 <term><varname>locale.LC_MESSAGES=
</varname></term>
224 <term><varname>locale.LC_PAPER=
</varname></term>
225 <term><varname>locale.LC_NAME=
</varname></term>
226 <term><varname>locale.LC_ADDRESS=
</varname></term>
227 <term><varname>locale.LC_TELEPHONE=
</varname></term>
228 <term><varname>locale.LC_MEASUREMENT=
</varname></term>
229 <term><varname>locale.LC_IDENTIFICATION=
</varname></term>
231 <para>Parameters understood by the system and service
232 manager to control locale and language settings. For
234 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
236 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
241 <term><varname>fsck.mode=
</varname></term>
242 <term><varname>fsck.repair=
</varname></term>
245 <para>Parameters understood by the file system checker
246 services. For details, see
247 <citerefentry><refentrytitle>systemd-fsck@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
249 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
254 <term><varname>quotacheck.mode=
</varname></term>
257 <para>Parameter understood by the file quota checker
258 service. For details, see
259 <citerefentry><refentrytitle>systemd-quotacheck.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
261 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
266 <term><varname>systemd.journald.forward_to_syslog=
</varname></term>
267 <term><varname>systemd.journald.forward_to_kmsg=
</varname></term>
268 <term><varname>systemd.journald.forward_to_console=
</varname></term>
269 <term><varname>systemd.journald.forward_to_wall=
</varname></term>
272 <para>Parameters understood by the journal service. For
274 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
276 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
281 <term><varname>vconsole.keymap=
</varname></term>
282 <term><varname>vconsole.keymap_toggle=
</varname></term>
283 <term><varname>vconsole.font=
</varname></term>
284 <term><varname>vconsole.font_map=
</varname></term>
285 <term><varname>vconsole.font_unimap=
</varname></term>
288 <para>Parameters understood by the virtual console setup logic. For details, see
289 <citerefentry><refentrytitle>vconsole.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
291 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
296 <term><varname>udev.log_level=
</varname></term>
297 <term><varname>rd.udev.log_level=
</varname></term>
298 <term><varname>udev.children_max=
</varname></term>
299 <term><varname>rd.udev.children_max=
</varname></term>
300 <term><varname>udev.exec_delay=
</varname></term>
301 <term><varname>rd.udev.exec_delay=
</varname></term>
302 <term><varname>udev.event_timeout=
</varname></term>
303 <term><varname>rd.udev.event_timeout=
</varname></term>
304 <term><varname>udev.timeout_signal=
</varname></term>
305 <term><varname>rd.udev.timeout_signal=
</varname></term>
306 <term><varname>udev.blockdev_read_only
</varname></term>
307 <term><varname>rd.udev.blockdev_read_only
</varname></term>
308 <term><varname>net.ifnames=
</varname></term>
309 <term><varname>net.naming-scheme=
</varname></term>
312 <para>Parameters understood by the device event managing
313 daemon. For details, see
314 <citerefentry><refentrytitle>systemd-udevd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
316 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
321 <term><varname>plymouth.enable=
</varname></term>
324 <para>May be used to disable the Plymouth boot splash. For
326 <citerefentry project='die-net'
><refentrytitle>plymouth
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
328 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
333 <term><varname>luks=
</varname></term>
334 <term><varname>rd.luks=
</varname></term>
335 <term><varname>luks.crypttab=
</varname></term>
336 <term><varname>rd.luks.crypttab=
</varname></term>
337 <term><varname>luks.name=
</varname></term>
338 <term><varname>rd.luks.name=
</varname></term>
339 <term><varname>luks.uuid=
</varname></term>
340 <term><varname>rd.luks.uuid=
</varname></term>
341 <term><varname>luks.options=
</varname></term>
342 <term><varname>rd.luks.options=
</varname></term>
343 <term><varname>luks.key=
</varname></term>
344 <term><varname>rd.luks.key=
</varname></term>
347 <para>Configures the LUKS full-disk encryption logic at
348 boot. For details, see
349 <citerefentry><refentrytitle>systemd-cryptsetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
351 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
356 <term><varname>fstab=
</varname></term>
357 <term><varname>rd.fstab=
</varname></term>
360 <para>Configures the
<filename>/etc/fstab
</filename> logic
361 at boot. For details, see
362 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
364 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
369 <term><varname>root=
</varname></term>
370 <term><varname>rootfstype=
</varname></term>
371 <term><varname>rootflags=
</varname></term>
372 <term><varname>ro
</varname></term>
373 <term><varname>rw
</varname></term>
376 <para>Configures the root file system and its file system type and mount options, as well as
377 whether it shall be mounted read-only or read-write initially. For details, see
378 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
380 <para>If
<varname>root=
</varname> is not set (or set to
<literal>gpt-auto
</literal>) the automatic
381 root partition discovery implemented by
382 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
383 will be in effect. In this case
<varname>rootfstype=
</varname>,
<varname>rootflags=
</varname>,
384 <varname>ro
</varname>,
<varname>rw
</varname> will be interpreted by
385 <command>systemd-gpt-auto-generator
</command>.
</para>
387 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
392 <term><varname>mount.usr=
</varname></term>
393 <term><varname>mount.usrfstype=
</varname></term>
394 <term><varname>mount.usrflags=
</varname></term>
397 <para>Configures the /usr file system (if required) and
398 its file system type and mount options. For details, see
399 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
401 <xi:include href=
"version-info.xml" xpointer=
"v235"/>
406 <term><varname>veritytab=
</varname></term>
407 <term><varname>rd.veritytab=
</varname></term>
408 <term><varname>roothash=
</varname></term>
409 <term><varname>systemd.verity=
</varname></term>
410 <term><varname>rd.systemd.verity=
</varname></term>
411 <term><varname>systemd.verity_root_data=
</varname></term>
412 <term><varname>systemd.verity_root_hash=
</varname></term>
413 <term><varname>systemd.verity.root_options=
</varname></term>
414 <term><varname>usrhash=
</varname></term>
415 <term><varname>systemd.verity_usr_data=
</varname></term>
416 <term><varname>systemd.verity_usr_hash=
</varname></term>
417 <term><varname>systemd.verity_usr_options=
</varname></term>
419 <para>Configures the integrity protection root hash for the root and
<filename>/usr
</filename> file systems, and other related
420 parameters. For details, see
421 <citerefentry><refentrytitle>systemd-veritysetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
423 <xi:include href=
"version-info.xml" xpointer=
"v233"/>
428 <term><varname>systemd.getty_auto=
</varname></term>
431 <para>Configures whether the
<filename>serial-getty@.service
</filename> will run.
433 <citerefentry><refentrytitle>systemd-getty-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
435 <xi:include href=
"version-info.xml" xpointer=
"v250"/>
440 <term><varname>systemd.gpt_auto=
</varname></term>
441 <term><varname>rd.systemd.gpt_auto=
</varname></term>
444 <para>Configures whether GPT-based partition auto-discovery shall be attempted. For details, see
445 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
447 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
452 <term><varname>systemd.image_policy=
</varname></term>
453 <term><varname>rd.systemd.image_policy=
</varname></term>
455 <listitem><para>When GPT-based partition auto-discovery is used, configures the image dissection
456 policy string to apply, as per
457 <citerefentry><refentrytitle>systemd.image-policy
</refentrytitle><manvolnum>7</manvolnum></citerefentry>. For
459 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
461 <xi:include href=
"version-info.xml" xpointer=
"v254"/></listitem>
465 <term><varname>systemd.default_timeout_start_sec=
</varname></term>
468 <para>Overrides the default start job timeout
<varname>DefaultTimeoutStartSec=
</varname> at
469 boot. For details, see
470 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
472 <xi:include href=
"version-info.xml" xpointer=
"v230"/>
477 <term><varname>systemd.default_device_timeout_sec=
</varname></term>
480 <para>Overrides the default device timeout
<varname>DefaultDeviceTimeoutSec=
</varname> at boot. For
482 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
484 <xi:include href=
"version-info.xml" xpointer=
"v254"/>
489 <term><varname>systemd.watchdog_device=
</varname></term>
492 <para>Overrides the watchdog device path
<varname>WatchdogDevice=
</varname>. For details, see
493 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
495 <xi:include href=
"version-info.xml" xpointer=
"v236"/>
500 <term><varname>systemd.watchdog_sec=
</varname></term>
503 <para>Overrides the watchdog timeout settings otherwise configured with
504 <varname>RuntimeWatchdog=
</varname>,
<varname>RebootWatchdog=
</varname> and
505 <varname>KExecWatchdogSec=
</varname>. Takes a time value (if no unit is specified, seconds is the
506 implicitly assumed time unit) or the special strings
<literal>off
</literal> or
507 <literal>default
</literal>. For details, see
508 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
510 <xi:include href=
"version-info.xml" xpointer=
"v250"/>
515 <term><varname>systemd.watchdog_pre_sec=
</varname></term>
518 <para>Overrides the watchdog pre-timeout settings otherwise configured with
519 <varname>RuntimeWatchdogPreSec=
</varname>. Takes a time value (if no unit is specified, seconds is the
520 implicitly assumed time unit) or the special strings
<literal>off
</literal> or
521 <literal>default
</literal>. For details, see
522 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
524 <xi:include href=
"version-info.xml" xpointer=
"v251"/>
529 <term><varname>systemd.watchdog_pretimeout_governor=
</varname></term>
532 <para>Overrides the watchdog pre-timeout settings otherwise configured with
533 <varname>RuntimeWatchdogPreGovernor=
</varname>. Takes a string value. For details, see
534 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
536 <xi:include href=
"version-info.xml" xpointer=
"v251"/>
541 <term><varname>systemd.cpu_affinity=
</varname></term>
544 <para>Overrides the CPU affinity mask for the service manager and the default for all child
545 processes it forks. This takes precedence over
<varname>CPUAffinity=
</varname>, see
546 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
549 <xi:include href=
"version-info.xml" xpointer=
"v245"/>
554 <term><varname>modules_load=
</varname></term>
555 <term><varname>rd.modules_load=
</varname></term>
558 <para>Load a specific kernel module early at boot. For
560 <citerefentry><refentrytitle>systemd-modules-load.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
562 <xi:include href=
"version-info.xml" xpointer=
"v187"/>
567 <term><varname>nameserver=
</varname></term>
568 <term><varname>domain=
</varname></term>
570 <listitem><para>Configures DNS server information and search domains, see
571 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
574 <xi:include href=
"version-info.xml" xpointer=
"v253"/></listitem>
578 <term><varname>resume=
</varname></term>
579 <term><varname>resumeflags=
</varname></term>
582 <para>Enables resume from hibernation using the specified
583 device and mount options. All
584 <citerefentry project='man-pages'
><refentrytitle>fstab
</refentrytitle><manvolnum>5</manvolnum></citerefentry>-like
585 paths are supported. For details, see
586 <citerefentry><refentrytitle>systemd-hibernate-resume-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
588 <xi:include href=
"version-info.xml" xpointer=
"v217"/>
593 <term><varname>systemd.firstboot=
</varname></term>
595 <listitem><para>Takes a boolean argument, defaults to on. If off,
596 <citerefentry><refentrytitle>systemd-firstboot.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
597 will not query the user for basic system settings, even if the system boots up for the first time and
598 the relevant settings are not initialized yet. Not to be confused with
599 <varname>systemd.condition-first-boot=
</varname> (see below), which overrides the result of the
600 <varname>ConditionFirstBoot=
</varname> unit file condition, and thus controls more than just
601 <filename>systemd-firstboot.service
</filename> behaviour.
</para>
603 <xi:include href=
"version-info.xml" xpointer=
"v233"/></listitem>
607 <term><varname>systemd.condition-needs-update=
</varname></term>
609 <listitem><para>Takes a boolean argument. If specified, overrides the result of
610 <varname>ConditionNeedsUpdate=
</varname> unit condition checks. See
611 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
614 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
618 <term><varname>systemd.condition-first-boot=
</varname></term>
620 <listitem><para>Takes a boolean argument. If specified, overrides the result of
621 <varname>ConditionFirstBoot=
</varname> unit condition checks. See
622 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
623 details. Not to be confused with
<varname>systemd.firstboot=
</varname> which only controls behaviour
624 of the
<filename>systemd-firstboot.service
</filename> system service but has no effect on the
625 condition check (see above).
</para>
627 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
631 <term><varname>systemd.clock-usec=
</varname></term>
633 <listitem><para>Takes a decimal, numeric timestamp in μs since January
1st
1970,
00:
00am, to set the
634 system clock to. The system time is set to the specified timestamp early during boot. It is not
635 propagated to the hardware clock (RTC).
</para>
637 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
641 <term><varname>systemd.random-seed=
</varname></term>
643 <listitem><para>Takes a base64 encoded random seed value to credit with full entropy to the kernel's
644 random pool during early service manager initialization. This option is useful in testing
645 environments where delays due to random pool initialization in entropy starved virtual machines shall
648 <para>Note that if this option is used the seed is accessible to unprivileged programs from
649 <filename>/proc/cmdline
</filename>. This option is hence a security risk when used outside of test
650 systems, since the (possibly) only seed used for initialization of the kernel's entropy pool might be
651 easily acquired by unprivileged programs.
</para>
653 <para>It is recommended to pass
512 bytes of randomized data (as that matches the Linux kernel pool
654 size), which may be generated with a command like the following:
</para>
656 <programlisting>dd if=/dev/urandom bs=
512 count=
1 status=none | base64 -w
0</programlisting>
658 <para>Again: do not use this option outside of testing environments, it's a security risk elsewhere,
659 as secret key material derived from the entropy pool can possibly be reconstructed by unprivileged
662 <xi:include href=
"version-info.xml" xpointer=
"v246"/>
667 <term><varname>systemd.hostname=
</varname></term>
669 <listitem><para>Accepts a hostname to set during early boot. If specified takes precedence over what
670 is set in
<filename>/etc/hostname
</filename>. Note that this does not bar later runtime changes to
671 the hostname, it simply controls the initial hostname set during early boot.
</para>
673 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
677 <term><varname>systemd.tty.term.
<replaceable>tty
</replaceable>=
</varname></term>
678 <term><varname>systemd.tty.rows.
<replaceable>tty
</replaceable>=
</varname></term>
679 <term><varname>systemd.tty.columns.
<replaceable>tty
</replaceable>=
</varname></term>
681 <listitem><para>These arguments allow configuring default values for
<varname>$TERM
</varname>,
682 <varname>TTYRows=
</varname>, and
<varname>TTYColumns=
</varname> for tty
683 <replaceable>tty
</replaceable>. Additionally,
<varname>systemd.tty.term.console
</varname> will
684 configure the
<varname>$TERM
</varname> value used by
<command>systemd
</command> if not set explicitly
685 using
<varname>TERM
</varname> on the kernel command line. The tty name should be specified without
686 the
<filename>/dev/
</filename> prefix (e.g.
<literal>systemd.tty.rows.ttyS0=
80</literal>).
689 <xi:include href=
"version-info.xml" xpointer=
"v254"/></listitem>
695 <title>History
</title>
699 <term>systemd
252</term>
700 <listitem><para>Kernel command-line arguments
<varname>systemd.unified_cgroup_hierarchy
</varname>
701 and
<varname>systemd.legacy_systemd_cgroup_controller
</varname> were deprecated. Please switch to
702 the unified cgroup hierarchy.
</para>
704 <xi:include href=
"version-info.xml" xpointer=
"v252"/></listitem>
710 <title>See Also
</title>
712 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
713 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
714 <citerefentry project='man-pages'
><refentrytitle>bootparam
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
715 <citerefentry><refentrytitle>systemd.system-credentials
</refentrytitle><manvolnum>7</manvolnum></citerefentry>
716 <citerefentry><refentrytitle>smbios-type-
11</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
717 <citerefentry project='man-pages'
><refentrytitle>dracut.cmdline
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
718 <citerefentry><refentrytitle>systemd-debug-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
719 <citerefentry><refentrytitle>systemd-fsck@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
720 <citerefentry><refentrytitle>systemd-quotacheck.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
721 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
722 <citerefentry><refentrytitle>systemd-vconsole-setup.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
723 <citerefentry><refentrytitle>systemd-udevd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
724 <citerefentry project='die-net'
><refentrytitle>plymouth
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
725 <citerefentry><refentrytitle>systemd-cryptsetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
726 <citerefentry><refentrytitle>systemd-veritysetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
727 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
728 <citerefentry><refentrytitle>systemd-getty-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
729 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
730 <citerefentry><refentrytitle>systemd-volatile-root.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
731 <citerefentry><refentrytitle>systemd-modules-load.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
732 <citerefentry><refentrytitle>systemd-backlight@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
733 <citerefentry><refentrytitle>systemd-rfkill.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
734 <citerefentry><refentrytitle>systemd-hibernate-resume-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
735 <citerefentry><refentrytitle>systemd-firstboot.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
736 <citerefentry><refentrytitle>bootctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>