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/4.5/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 the documentation of the specific initrd
44 implementation of your installation.
</para>
48 <title>Core OS Command Line Arguments
</title>
50 <variablelist class='kernel-commandline-options'
>
52 <term><varname>systemd.unit=
</varname></term>
53 <term><varname>rd.systemd.unit=
</varname></term>
54 <term><varname>systemd.dump_core
</varname></term>
55 <term><varname>systemd.crash_chvt
</varname></term>
56 <term><varname>systemd.crash_shell
</varname></term>
57 <term><varname>systemd.crash_reboot
</varname></term>
58 <term><varname>systemd.confirm_spawn
</varname></term>
59 <term><varname>systemd.service_watchdogs
</varname></term>
60 <term><varname>systemd.show_status
</varname></term>
61 <term><varname>systemd.status_unit_format=
</varname></term>
62 <term><varname>systemd.log_target=
</varname></term>
63 <term><varname>systemd.log_level=
</varname></term>
64 <term><varname>systemd.log_location=
</varname></term>
65 <term><varname>systemd.log_color
</varname></term>
66 <term><varname>systemd.log_ratelimit_kmsg
</varname></term>
67 <term><varname>systemd.default_standard_output=
</varname></term>
68 <term><varname>systemd.default_standard_error=
</varname></term>
69 <term><varname>systemd.setenv=
</varname></term>
70 <term><varname>systemd.machine_id=
</varname></term>
71 <term><varname>systemd.set_credential=
</varname></term>
72 <term><varname>systemd.set_credential_binary=
</varname></term>
73 <term><varname>systemd.import_credentials=
</varname></term>
74 <term><varname>systemd.reload_limit_interval_sec=
</varname></term>
75 <term><varname>systemd.reload_limit_burst=
</varname></term>
77 <para>Parameters understood by the system and service
78 manager to control system behavior. For details, see
79 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
81 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
86 <term><varname>systemd.mask=
</varname></term>
87 <term><varname>systemd.wants=
</varname></term>
88 <term><varname>systemd.debug_shell
</varname></term>
90 <para>Additional parameters understood by
91 <citerefentry><refentrytitle>systemd-debug-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
92 to mask or start specific units at boot, or invoke a debug
95 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
100 <term><varname>systemd.run=
</varname></term>
101 <term><varname>systemd.run_success_action=
</varname></term>
102 <term><varname>systemd.run_failure_action=
</varname></term>
104 <para>Additional parameters understood by
105 <citerefentry><refentrytitle>systemd-run-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>, to
106 run a command line specified on the kernel command line as system service after booting up.
</para>
108 <xi:include href=
"version-info.xml" xpointer=
"v240"/>
113 <term><varname>systemd.early_core_pattern=
</varname></term>
115 <para>During early boot, the generation of core dump files is disabled until a core dump handler (if any)
116 takes over. This parameter allows specifying an absolute path where core dump files should be stored until
117 a handler is installed. The path should be absolute and may contain specifiers, see
118 <citerefentry project='man-pages'
><refentrytitle>core
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.
</para>
120 <xi:include href=
"version-info.xml" xpointer=
"v240"/>
125 <term><varname>systemd.restore_state=
</varname></term>
127 <para>This parameter is understood by several system tools
128 to control whether or not they should restore system state
129 from the previous boot. For details, see
130 <citerefentry><refentrytitle>systemd-backlight@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
132 <citerefentry><refentrytitle>systemd-rfkill.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
135 <xi:include href=
"version-info.xml" xpointer=
"v209"/>
140 <term><varname>systemd.ssh_auto=
</varname></term>
141 <term><varname>systemd.ssh_listen=
</varname></term>
143 <para>These parameters are interpreted by
144 <citerefentry><refentrytitle>systemd-ssh-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
145 and may be used to control SSH sockets the system shall be reachable on.
</para>
147 <xi:include href=
"version-info.xml" xpointer=
"v256"/>
152 <term><varname>systemd.volatile=
</varname></term>
154 <para>This parameter controls whether the system shall boot up in volatile mode. Takes a boolean argument, or
155 the special value
<literal>state
</literal>. If false (the default), normal boot mode is selected, the root
156 directory and
<filename>/var/
</filename> are mounted as specified on the kernel command line or
157 <filename>/etc/fstab
</filename>, or otherwise configured. If true, full state-less boot mode is selected. In
158 this case the root directory is mounted as volatile memory file system (
<literal>tmpfs
</literal>), and only
159 <filename>/usr/
</filename> is mounted from the file system configured as root device, in read-only mode. This
160 enables fully state-less boots were the vendor-supplied OS is used as shipped, with only default
161 configuration and no stored state in effect, as
<filename>/etc/
</filename> and
<filename>/var/
</filename> (as
162 well as all other resources shipped in the root file system) are reset at boot and lost on shutdown. If this
163 setting is set to
<literal>state
</literal> the root file system is mounted read-only, however
164 <filename>/var/
</filename> is mounted as a volatile memory file system (
<literal>tmpfs
</literal>), so that the
165 system boots up with the normal configuration applied, but all state reset at boot and lost at shutdown. If
166 this setting is set to
<literal>overlay
</literal> the root file system is set up as
167 <literal>overlayfs
</literal> mount combining the read-only root directory with a writable
168 <literal>tmpfs
</literal>, so that no modifications are made to disk, but the file system may be modified
169 nonetheless with all changes being lost at reboot. For details, see
170 <citerefentry><refentrytitle>systemd-volatile-root.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
172 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
174 <xi:include href=
"version-info.xml" xpointer=
"v233"/>
179 <term><varname>quiet
</varname></term>
181 <para>Parameter understood by both the kernel and the system
182 and service manager to control console log verbosity. For
184 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
186 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
191 <term><varname>debug
</varname></term>
193 <para>Parameter understood by both the kernel and the system
194 and service manager to control console log verbosity. For
196 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
198 <xi:include href=
"version-info.xml" xpointer=
"v205"/>
203 <term><varname>-b
</varname></term>
204 <term><varname>rd.emergency
</varname></term>
205 <term><varname>emergency
</varname></term>
206 <term><varname>rd.rescue
</varname></term>
207 <term><varname>rescue
</varname></term>
208 <term><varname>single
</varname></term>
209 <term><varname>s
</varname></term>
210 <term><varname>S
</varname></term>
211 <term><varname>1</varname></term>
212 <term><varname>2</varname></term>
213 <term><varname>3</varname></term>
214 <term><varname>4</varname></term>
215 <term><varname>5</varname></term>
217 <para>Parameters understood by the system and service
218 manager, as compatibility and convenience options. For details, see
219 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
221 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
226 <term><varname>locale.LANG=
</varname></term>
227 <term><varname>locale.LANGUAGE=
</varname></term>
228 <term><varname>locale.LC_CTYPE=
</varname></term>
229 <term><varname>locale.LC_NUMERIC=
</varname></term>
230 <term><varname>locale.LC_TIME=
</varname></term>
231 <term><varname>locale.LC_COLLATE=
</varname></term>
232 <term><varname>locale.LC_MONETARY=
</varname></term>
233 <term><varname>locale.LC_MESSAGES=
</varname></term>
234 <term><varname>locale.LC_PAPER=
</varname></term>
235 <term><varname>locale.LC_NAME=
</varname></term>
236 <term><varname>locale.LC_ADDRESS=
</varname></term>
237 <term><varname>locale.LC_TELEPHONE=
</varname></term>
238 <term><varname>locale.LC_MEASUREMENT=
</varname></term>
239 <term><varname>locale.LC_IDENTIFICATION=
</varname></term>
241 <para>Parameters understood by the system and service
242 manager to control locale and language settings. For
244 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
246 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
251 <term><varname>fsck.mode=
</varname></term>
252 <term><varname>fsck.repair=
</varname></term>
255 <para>Parameters understood by the file system checker
256 services. For details, see
257 <citerefentry><refentrytitle>systemd-fsck@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
259 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
264 <term><varname>quotacheck.mode=
</varname></term>
267 <para>Parameter understood by the file quota checker
268 service. For details, see
269 <citerefentry><refentrytitle>systemd-quotacheck.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
271 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
276 <term><varname>systemd.journald.forward_to_syslog=
</varname></term>
277 <term><varname>systemd.journald.forward_to_kmsg=
</varname></term>
278 <term><varname>systemd.journald.forward_to_console=
</varname></term>
279 <term><varname>systemd.journald.forward_to_wall=
</varname></term>
282 <para>Parameters understood by the journal service. For
284 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
286 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
291 <term><varname>vconsole.keymap=
</varname></term>
292 <term><varname>vconsole.keymap_toggle=
</varname></term>
293 <term><varname>vconsole.font=
</varname></term>
294 <term><varname>vconsole.font_map=
</varname></term>
295 <term><varname>vconsole.font_unimap=
</varname></term>
298 <para>Parameters understood by the virtual console setup logic. For details, see
299 <citerefentry><refentrytitle>vconsole.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
301 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
306 <term><varname>udev.log_level=
</varname></term>
307 <term><varname>rd.udev.log_level=
</varname></term>
308 <term><varname>udev.children_max=
</varname></term>
309 <term><varname>rd.udev.children_max=
</varname></term>
310 <term><varname>udev.exec_delay=
</varname></term>
311 <term><varname>rd.udev.exec_delay=
</varname></term>
312 <term><varname>udev.event_timeout=
</varname></term>
313 <term><varname>rd.udev.event_timeout=
</varname></term>
314 <term><varname>udev.timeout_signal=
</varname></term>
315 <term><varname>rd.udev.timeout_signal=
</varname></term>
316 <term><varname>udev.blockdev_read_only
</varname></term>
317 <term><varname>rd.udev.blockdev_read_only
</varname></term>
318 <term><varname>net.ifnames=
</varname></term>
319 <term><varname>net.naming-scheme=
</varname></term>
322 <para>Parameters understood by the device event managing
323 daemon. For details, see
324 <citerefentry><refentrytitle>systemd-udevd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
326 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
331 <term><varname>plymouth.enable=
</varname></term>
334 <para>May be used to disable the Plymouth boot splash. For
336 <citerefentry project='die-net'
><refentrytitle>plymouth
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
338 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
343 <term><varname>luks=
</varname></term>
344 <term><varname>rd.luks=
</varname></term>
345 <term><varname>luks.crypttab=
</varname></term>
346 <term><varname>rd.luks.crypttab=
</varname></term>
347 <term><varname>luks.name=
</varname></term>
348 <term><varname>rd.luks.name=
</varname></term>
349 <term><varname>luks.uuid=
</varname></term>
350 <term><varname>rd.luks.uuid=
</varname></term>
351 <term><varname>luks.options=
</varname></term>
352 <term><varname>rd.luks.options=
</varname></term>
353 <term><varname>luks.key=
</varname></term>
354 <term><varname>rd.luks.key=
</varname></term>
357 <para>Configures the LUKS full-disk encryption logic at
358 boot. For details, see
359 <citerefentry><refentrytitle>systemd-cryptsetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
361 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
366 <term><varname>fstab=
</varname></term>
367 <term><varname>rd.fstab=
</varname></term>
370 <para>Configures the
<filename>/etc/fstab
</filename> logic
371 at boot. For details, see
372 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
374 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
379 <term><varname>root=
</varname></term>
380 <term><varname>rootfstype=
</varname></term>
381 <term><varname>rootflags=
</varname></term>
382 <term><varname>ro
</varname></term>
383 <term><varname>rw
</varname></term>
386 <para>Configures the root file system and its file system type and mount options, as well as
387 whether it shall be mounted read-only or read-write initially. For details, see
388 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
390 <para>If
<varname>root=
</varname> is not set (or set to
<literal>gpt-auto
</literal>) the automatic
391 root partition discovery implemented by
392 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
393 will be in effect. In this case
<varname>rootfstype=
</varname>,
<varname>rootflags=
</varname>,
394 <varname>ro
</varname>,
<varname>rw
</varname> will be interpreted by
395 <command>systemd-gpt-auto-generator
</command>.
</para>
397 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
402 <term><varname>mount.usr=
</varname></term>
403 <term><varname>mount.usrfstype=
</varname></term>
404 <term><varname>mount.usrflags=
</varname></term>
407 <para>Configures the /usr file system (if required) and
408 its file system type and mount options. For details, see
409 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
411 <xi:include href=
"version-info.xml" xpointer=
"v235"/>
416 <term><varname>veritytab=
</varname></term>
417 <term><varname>rd.veritytab=
</varname></term>
418 <term><varname>roothash=
</varname></term>
419 <term><varname>systemd.verity=
</varname></term>
420 <term><varname>rd.systemd.verity=
</varname></term>
421 <term><varname>systemd.verity_root_data=
</varname></term>
422 <term><varname>systemd.verity_root_hash=
</varname></term>
423 <term><varname>systemd.verity.root_options=
</varname></term>
424 <term><varname>usrhash=
</varname></term>
425 <term><varname>systemd.verity_usr_data=
</varname></term>
426 <term><varname>systemd.verity_usr_hash=
</varname></term>
427 <term><varname>systemd.verity_usr_options=
</varname></term>
429 <para>Configures the integrity protection root hash for the root and
<filename>/usr
</filename> file systems, and other related
430 parameters. For details, see
431 <citerefentry><refentrytitle>systemd-veritysetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
433 <xi:include href=
"version-info.xml" xpointer=
"v233"/>
438 <term><varname>systemd.getty_auto=
</varname></term>
441 <para>Configures whether the
<filename>serial-getty@.service
</filename> will run.
443 <citerefentry><refentrytitle>systemd-getty-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
445 <xi:include href=
"version-info.xml" xpointer=
"v250"/>
450 <term><varname>systemd.gpt_auto=
</varname></term>
451 <term><varname>rd.systemd.gpt_auto=
</varname></term>
454 <para>Configures whether GPT-based partition auto-discovery shall be attempted. For details, see
455 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
457 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
462 <term><varname>systemd.image_policy=
</varname></term>
463 <term><varname>rd.systemd.image_policy=
</varname></term>
465 <listitem><para>When GPT-based partition auto-discovery is used, configures the image dissection
466 policy string to apply, as per
467 <citerefentry><refentrytitle>systemd.image-policy
</refentrytitle><manvolnum>7</manvolnum></citerefentry>. For
469 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
471 <xi:include href=
"version-info.xml" xpointer=
"v254"/></listitem>
475 <term><varname>systemd.default_timeout_start_sec=
</varname></term>
478 <para>Overrides the default start job timeout
<varname>DefaultTimeoutStartSec=
</varname> at
479 boot. For details, see
480 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
482 <xi:include href=
"version-info.xml" xpointer=
"v230"/>
487 <term><varname>systemd.default_device_timeout_sec=
</varname></term>
490 <para>Overrides the default device timeout
<varname>DefaultDeviceTimeoutSec=
</varname> at boot. For
492 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
494 <xi:include href=
"version-info.xml" xpointer=
"v254"/>
499 <term><varname>systemd.watchdog_device=
</varname></term>
502 <para>Overrides the watchdog device path
<varname>WatchdogDevice=
</varname>. For details, see
503 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
505 <xi:include href=
"version-info.xml" xpointer=
"v236"/>
510 <term><varname>systemd.watchdog_sec=
</varname></term>
513 <para>Overrides the watchdog timeout settings otherwise configured with
514 <varname>RuntimeWatchdog=
</varname>,
<varname>RebootWatchdog=
</varname> and
515 <varname>KExecWatchdogSec=
</varname>. Takes a time value (if no unit is specified, seconds is the
516 implicitly assumed time unit) or the special strings
<literal>off
</literal> or
517 <literal>default
</literal>. For details, see
518 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
520 <xi:include href=
"version-info.xml" xpointer=
"v250"/>
525 <term><varname>systemd.watchdog_pre_sec=
</varname></term>
528 <para>Overrides the watchdog pre-timeout settings otherwise configured with
529 <varname>RuntimeWatchdogPreSec=
</varname>. Takes a time value (if no unit is specified, seconds is the
530 implicitly assumed time unit) or the special strings
<literal>off
</literal> or
531 <literal>default
</literal>. For details, see
532 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
534 <xi:include href=
"version-info.xml" xpointer=
"v251"/>
539 <term><varname>systemd.watchdog_pretimeout_governor=
</varname></term>
542 <para>Overrides the watchdog pre-timeout settings otherwise configured with
543 <varname>RuntimeWatchdogPreGovernor=
</varname>. Takes a string value. For details, see
544 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
546 <xi:include href=
"version-info.xml" xpointer=
"v251"/>
551 <term><varname>systemd.cpu_affinity=
</varname></term>
554 <para>Overrides the CPU affinity mask for the service manager and the default for all child
555 processes it forks. This takes precedence over
<varname>CPUAffinity=
</varname>, see
556 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
559 <xi:include href=
"version-info.xml" xpointer=
"v245"/>
564 <term><varname>modules_load=
</varname></term>
565 <term><varname>rd.modules_load=
</varname></term>
568 <para>Load a specific kernel module early at boot. For
570 <citerefentry><refentrytitle>systemd-modules-load.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
572 <xi:include href=
"version-info.xml" xpointer=
"v187"/>
577 <term><varname>nameserver=
</varname></term>
578 <term><varname>domain=
</varname></term>
580 <listitem><para>Configures DNS server information and search domains, see
581 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
584 <xi:include href=
"version-info.xml" xpointer=
"v253"/></listitem>
588 <term><varname>resume=
</varname></term>
589 <term><varname>resumeflags=
</varname></term>
592 <para>Enables resume from hibernation using the specified
593 device and mount options. All
594 <citerefentry project='man-pages'
><refentrytitle>fstab
</refentrytitle><manvolnum>5</manvolnum></citerefentry>-like
595 paths are supported. For details, see
596 <citerefentry><refentrytitle>systemd-hibernate-resume-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
598 <xi:include href=
"version-info.xml" xpointer=
"v217"/>
603 <term><varname>systemd.firstboot=
</varname></term>
605 <listitem><para>Takes a boolean argument, defaults to on. If off,
606 <citerefentry><refentrytitle>systemd-firstboot.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
608 <citerefentry><refentrytitle>systemd-homed-firstboot.service
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
609 will not query the user for basic system settings, even if the system boots up for the first time and
610 the relevant settings are not initialized yet. Not to be confused with
611 <varname>systemd.condition-first-boot=
</varname> (see below), which overrides the result of the
612 <varname>ConditionFirstBoot=
</varname> unit file condition, and thus controls more than just
613 <filename>systemd-firstboot.service
</filename> behaviour.
</para>
615 <xi:include href=
"version-info.xml" xpointer=
"v233"/></listitem>
619 <term><varname>systemd.condition-needs-update=
</varname></term>
621 <listitem><para>Takes a boolean argument. If specified, overrides the result of
622 <varname>ConditionNeedsUpdate=
</varname> unit condition checks. See
623 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
626 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
630 <term><varname>systemd.condition-first-boot=
</varname></term>
632 <listitem><para>Takes a boolean argument. If specified, overrides the result of
633 <varname>ConditionFirstBoot=
</varname> unit condition checks. See
634 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
635 details. Not to be confused with
<varname>systemd.firstboot=
</varname> which only controls behaviour
636 of the
<filename>systemd-firstboot.service
</filename> system service but has no effect on the
637 condition check (see above).
</para>
639 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
643 <term><varname>systemd.clock-usec=
</varname></term>
645 <listitem><para>Takes a decimal, numeric timestamp in μs since January
1st
1970,
00:
00am, to set the
646 system clock to. The system time is set to the specified timestamp early during boot. It is not
647 propagated to the hardware clock (RTC).
</para>
649 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
653 <term><varname>systemd.random-seed=
</varname></term>
655 <listitem><para>Takes a base64 encoded random seed value to credit with full entropy to the kernel's
656 random pool during early service manager initialization. This option is useful in testing
657 environments where delays due to random pool initialization in entropy starved virtual machines shall
660 <para>Note that if this option is used the seed is accessible to unprivileged programs from
661 <filename>/proc/cmdline
</filename>. This option is hence a security risk when used outside of test
662 systems, since the (possibly) only seed used for initialization of the kernel's entropy pool might be
663 easily acquired by unprivileged programs.
</para>
665 <para>It is recommended to pass
512 bytes of randomized data (as that matches the Linux kernel pool
666 size), which may be generated with a command like the following:
</para>
668 <programlisting>dd if=/dev/urandom bs=
512 count=
1 status=none | base64 -w
0</programlisting>
670 <para>Again: do not use this option outside of testing environments, it's a security risk elsewhere,
671 as secret key material derived from the entropy pool can possibly be reconstructed by unprivileged
674 <xi:include href=
"version-info.xml" xpointer=
"v246"/>
679 <term><varname>systemd.hostname=
</varname></term>
681 <listitem><para>Accepts a hostname to set during early boot. If specified takes precedence over what
682 is set in
<filename>/etc/hostname
</filename>. Note that this does not bar later runtime changes to
683 the hostname, it simply controls the initial hostname set during early boot.
</para>
685 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
689 <term><varname>systemd.tty.term.
<replaceable>tty
</replaceable>=
</varname></term>
690 <term><varname>systemd.tty.rows.
<replaceable>tty
</replaceable>=
</varname></term>
691 <term><varname>systemd.tty.columns.
<replaceable>tty
</replaceable>=
</varname></term>
693 <listitem><para>These arguments allow configuring default values for
<varname>$TERM
</varname>,
694 <varname>TTYRows=
</varname>, and
<varname>TTYColumns=
</varname> for tty
695 <replaceable>tty
</replaceable>. Additionally,
<varname>systemd.tty.term.console
</varname> will
696 configure the
<varname>$TERM
</varname> value used by
<command>systemd
</command> if not set explicitly
697 using
<varname>TERM
</varname> on the kernel command line. The tty name should be specified without
698 the
<filename>/dev/
</filename> prefix (e.g.
<literal>systemd.tty.rows.ttyS0=
80</literal>).
701 <xi:include href=
"version-info.xml" xpointer=
"v254"/></listitem>
707 <title>History
</title>
711 <term>systemd
252</term>
712 <listitem><para>Kernel command-line arguments
<varname>systemd.unified_cgroup_hierarchy
</varname>
713 and
<varname>systemd.legacy_systemd_cgroup_controller
</varname> were deprecated. Please switch to
714 the unified cgroup hierarchy.
</para>
716 <xi:include href=
"version-info.xml" xpointer=
"v252"/></listitem>
722 <title>See Also
</title>
723 <para><simplelist type=
"inline">
724 <member><citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
725 <member><citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
726 <member><citerefentry project='man-pages'
><refentrytitle>bootparam
</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
727 <member><citerefentry><refentrytitle>systemd.system-credentials
</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
728 <member><citerefentry><refentrytitle>smbios-type-
11</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
729 <member><citerefentry><refentrytitle>systemd-debug-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
730 <member><citerefentry><refentrytitle>systemd-fsck@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
731 <member><citerefentry><refentrytitle>systemd-quotacheck.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
732 <member><citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
733 <member><citerefentry><refentrytitle>systemd-vconsole-setup.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
734 <member><citerefentry><refentrytitle>systemd-udevd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
735 <member><citerefentry project='die-net'
><refentrytitle>plymouth
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
736 <member><citerefentry><refentrytitle>systemd-cryptsetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
737 <member><citerefentry><refentrytitle>systemd-veritysetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
738 <member><citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
739 <member><citerefentry><refentrytitle>systemd-getty-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
740 <member><citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
741 <member><citerefentry><refentrytitle>systemd-volatile-root.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
742 <member><citerefentry><refentrytitle>systemd-modules-load.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
743 <member><citerefentry><refentrytitle>systemd-backlight@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
744 <member><citerefentry><refentrytitle>systemd-rfkill.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
745 <member><citerefentry><refentrytitle>systemd-hibernate-resume-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
746 <member><citerefentry><refentrytitle>systemd-firstboot.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
747 <member><citerefentry><refentrytitle>bootctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>