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>
89 <term><varname>systemd.default_debug_tty=
</varname></term>
91 <para>Additional parameters understood by
92 <citerefentry><refentrytitle>systemd-debug-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
93 to mask or start specific units at boot, or invoke a debug
96 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
101 <term><varname>systemd.run=
</varname></term>
102 <term><varname>systemd.run_success_action=
</varname></term>
103 <term><varname>systemd.run_failure_action=
</varname></term>
105 <para>Additional parameters understood by
106 <citerefentry><refentrytitle>systemd-run-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>, to
107 run a command line specified on the kernel command line as system service after booting up.
</para>
109 <xi:include href=
"version-info.xml" xpointer=
"v240"/>
114 <term><varname>systemd.early_core_pattern=
</varname></term>
116 <para>During early boot, the generation of core dump files is disabled until a core dump handler (if any)
117 takes over. This parameter allows specifying an absolute path where core dump files should be stored until
118 a handler is installed. The path should be absolute and may contain specifiers, see
119 <citerefentry project='man-pages'
><refentrytitle>core
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.
</para>
121 <xi:include href=
"version-info.xml" xpointer=
"v240"/>
126 <term><varname>systemd.restore_state=
</varname></term>
128 <para>This parameter is understood by several system tools
129 to control whether or not they should restore system state
130 from the previous boot. For details, see
131 <citerefentry><refentrytitle>systemd-backlight@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
133 <citerefentry><refentrytitle>systemd-rfkill.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
136 <xi:include href=
"version-info.xml" xpointer=
"v209"/>
141 <term><varname>systemd.ssh_auto=
</varname></term>
142 <term><varname>systemd.ssh_listen=
</varname></term>
144 <para>These parameters are interpreted by
145 <citerefentry><refentrytitle>systemd-ssh-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
146 and may be used to control SSH sockets the system shall be reachable on.
</para>
148 <xi:include href=
"version-info.xml" xpointer=
"v256"/>
153 <term><varname>systemd.volatile=
</varname></term>
155 <para>This parameter controls whether the system shall boot up in volatile mode. Takes a boolean argument, or
156 the special value
<literal>state
</literal>. If false (the default), normal boot mode is selected, the root
157 directory and
<filename>/var/
</filename> are mounted as specified on the kernel command line or
158 <filename>/etc/fstab
</filename>, or otherwise configured. If true, full state-less boot mode is selected. In
159 this case the root directory is mounted as volatile memory file system (
<literal>tmpfs
</literal>), and only
160 <filename>/usr/
</filename> is mounted from the file system configured as root device, in read-only mode. This
161 enables fully state-less boots were the vendor-supplied OS is used as shipped, with only default
162 configuration and no stored state in effect, as
<filename>/etc/
</filename> and
<filename>/var/
</filename> (as
163 well as all other resources shipped in the root file system) are reset at boot and lost on shutdown. If this
164 setting is set to
<literal>state
</literal> the root file system is mounted read-only, however
165 <filename>/var/
</filename> is mounted as a volatile memory file system (
<literal>tmpfs
</literal>), so that the
166 system boots up with the normal configuration applied, but all state reset at boot and lost at shutdown. If
167 this setting is set to
<literal>overlay
</literal> the root file system is set up as
168 <literal>overlayfs
</literal> mount combining the read-only root directory with a writable
169 <literal>tmpfs
</literal>, so that no modifications are made to disk, but the file system may be modified
170 nonetheless with all changes being lost at reboot. For details, see
171 <citerefentry><refentrytitle>systemd-volatile-root.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
173 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
175 <xi:include href=
"version-info.xml" xpointer=
"v233"/>
180 <term><varname>quiet
</varname></term>
182 <para>Parameter understood by both the kernel and the system
183 and service manager to control console log verbosity. For
185 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
187 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
192 <term><varname>debug
</varname></term>
194 <para>Parameter understood by both the kernel and the system
195 and service manager to control console log verbosity. For
197 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
199 <xi:include href=
"version-info.xml" xpointer=
"v205"/>
204 <term><varname>-b
</varname></term>
205 <term><varname>rd.emergency
</varname></term>
206 <term><varname>emergency
</varname></term>
207 <term><varname>rd.rescue
</varname></term>
208 <term><varname>rescue
</varname></term>
209 <term><varname>single
</varname></term>
210 <term><varname>s
</varname></term>
211 <term><varname>S
</varname></term>
212 <term><varname>1</varname></term>
213 <term><varname>2</varname></term>
214 <term><varname>3</varname></term>
215 <term><varname>4</varname></term>
216 <term><varname>5</varname></term>
218 <para>Parameters understood by the system and service
219 manager, as compatibility and convenience options. For details, see
220 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
222 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
227 <term><varname>locale.LANG=
</varname></term>
228 <term><varname>locale.LANGUAGE=
</varname></term>
229 <term><varname>locale.LC_CTYPE=
</varname></term>
230 <term><varname>locale.LC_NUMERIC=
</varname></term>
231 <term><varname>locale.LC_TIME=
</varname></term>
232 <term><varname>locale.LC_COLLATE=
</varname></term>
233 <term><varname>locale.LC_MONETARY=
</varname></term>
234 <term><varname>locale.LC_MESSAGES=
</varname></term>
235 <term><varname>locale.LC_PAPER=
</varname></term>
236 <term><varname>locale.LC_NAME=
</varname></term>
237 <term><varname>locale.LC_ADDRESS=
</varname></term>
238 <term><varname>locale.LC_TELEPHONE=
</varname></term>
239 <term><varname>locale.LC_MEASUREMENT=
</varname></term>
240 <term><varname>locale.LC_IDENTIFICATION=
</varname></term>
242 <para>Parameters understood by the system and service
243 manager to control locale and language settings. For
245 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
</para>
247 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
252 <term><varname>fsck.mode=
</varname></term>
253 <term><varname>fsck.repair=
</varname></term>
256 <para>Parameters understood by the file system checker
257 services. For details, see
258 <citerefentry><refentrytitle>systemd-fsck@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
260 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
265 <term><varname>quotacheck.mode=
</varname></term>
268 <para>Parameter understood by the file quota checker
269 service. For details, see
270 <citerefentry><refentrytitle>systemd-quotacheck.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
272 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
277 <term><varname>systemd.journald.forward_to_syslog=
</varname></term>
278 <term><varname>systemd.journald.forward_to_kmsg=
</varname></term>
279 <term><varname>systemd.journald.forward_to_console=
</varname></term>
280 <term><varname>systemd.journald.forward_to_wall=
</varname></term>
283 <para>Parameters understood by the journal service. For
285 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
287 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
292 <term><varname>vconsole.keymap=
</varname></term>
293 <term><varname>vconsole.keymap_toggle=
</varname></term>
294 <term><varname>vconsole.font=
</varname></term>
295 <term><varname>vconsole.font_map=
</varname></term>
296 <term><varname>vconsole.font_unimap=
</varname></term>
299 <para>Parameters understood by the virtual console setup logic. For details, see
300 <citerefentry><refentrytitle>vconsole.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
302 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
307 <term><varname>udev.log_level=
</varname></term>
308 <term><varname>rd.udev.log_level=
</varname></term>
309 <term><varname>udev.children_max=
</varname></term>
310 <term><varname>rd.udev.children_max=
</varname></term>
311 <term><varname>udev.exec_delay=
</varname></term>
312 <term><varname>rd.udev.exec_delay=
</varname></term>
313 <term><varname>udev.event_timeout=
</varname></term>
314 <term><varname>rd.udev.event_timeout=
</varname></term>
315 <term><varname>udev.timeout_signal=
</varname></term>
316 <term><varname>rd.udev.timeout_signal=
</varname></term>
317 <term><varname>udev.blockdev_read_only
</varname></term>
318 <term><varname>rd.udev.blockdev_read_only
</varname></term>
319 <term><varname>net.ifnames=
</varname></term>
320 <term><varname>net.naming_scheme=
</varname></term>
323 <para>Parameters understood by the device event managing
324 daemon. For details, see
325 <citerefentry><refentrytitle>systemd-udevd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
327 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
332 <term><varname>plymouth.enable=
</varname></term>
335 <para>May be used to disable the Plymouth boot splash. For
337 <citerefentry project='die-net'
><refentrytitle>plymouth
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
339 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
344 <term><varname>luks=
</varname></term>
345 <term><varname>rd.luks=
</varname></term>
346 <term><varname>luks.crypttab=
</varname></term>
347 <term><varname>rd.luks.crypttab=
</varname></term>
348 <term><varname>luks.name=
</varname></term>
349 <term><varname>rd.luks.name=
</varname></term>
350 <term><varname>luks.uuid=
</varname></term>
351 <term><varname>rd.luks.uuid=
</varname></term>
352 <term><varname>luks.options=
</varname></term>
353 <term><varname>rd.luks.options=
</varname></term>
354 <term><varname>luks.key=
</varname></term>
355 <term><varname>rd.luks.key=
</varname></term>
358 <para>Configures the LUKS full-disk encryption logic at
359 boot. For details, see
360 <citerefentry><refentrytitle>systemd-cryptsetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
362 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
367 <term><varname>fstab=
</varname></term>
368 <term><varname>rd.fstab=
</varname></term>
371 <para>Configures the
<filename>/etc/fstab
</filename> logic
372 at boot. For details, see
373 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
375 <xi:include href=
"version-info.xml" xpointer=
"v186"/>
380 <term><varname>root=
</varname></term>
381 <term><varname>rootfstype=
</varname></term>
382 <term><varname>rootflags=
</varname></term>
383 <term><varname>ro
</varname></term>
384 <term><varname>rw
</varname></term>
387 <para>Configures the root file system and its file system type and mount options, as well as
388 whether it shall be mounted read-only or read-write initially. For details, see
389 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
391 <para>If
<varname>root=
</varname> is not set (or set to
<literal>gpt-auto
</literal>) the automatic
392 root partition discovery implemented by
393 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
394 will be in effect. In this case
<varname>rootfstype=
</varname>,
<varname>rootflags=
</varname>,
395 <varname>ro
</varname>,
<varname>rw
</varname> will be interpreted by
396 <command>systemd-gpt-auto-generator
</command>.
</para>
398 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
403 <term><varname>mount.usr=
</varname></term>
404 <term><varname>mount.usrfstype=
</varname></term>
405 <term><varname>mount.usrflags=
</varname></term>
408 <para>Configures the /usr file system (if required) and
409 its file system type and mount options. For details, see
410 <citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
412 <xi:include href=
"version-info.xml" xpointer=
"v235"/>
417 <term><varname>veritytab=
</varname></term>
418 <term><varname>rd.veritytab=
</varname></term>
419 <term><varname>roothash=
</varname></term>
420 <term><varname>systemd.verity=
</varname></term>
421 <term><varname>rd.systemd.verity=
</varname></term>
422 <term><varname>systemd.verity_root_data=
</varname></term>
423 <term><varname>systemd.verity_root_hash=
</varname></term>
424 <term><varname>systemd.verity.root_options=
</varname></term>
425 <term><varname>usrhash=
</varname></term>
426 <term><varname>systemd.verity_usr_data=
</varname></term>
427 <term><varname>systemd.verity_usr_hash=
</varname></term>
428 <term><varname>systemd.verity_usr_options=
</varname></term>
430 <para>Configures the integrity protection root hash for the root and
<filename>/usr
</filename> file systems, and other related
431 parameters. For details, see
432 <citerefentry><refentrytitle>systemd-veritysetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
434 <xi:include href=
"version-info.xml" xpointer=
"v233"/>
439 <term><varname>systemd.getty_auto=
</varname></term>
442 <para>Configures whether the
<filename>serial-getty@.service
</filename> will run.
444 <citerefentry><refentrytitle>systemd-getty-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
446 <xi:include href=
"version-info.xml" xpointer=
"v250"/>
451 <term><varname>systemd.gpt_auto=
</varname></term>
452 <term><varname>rd.systemd.gpt_auto=
</varname></term>
455 <para>Configures whether GPT-based partition auto-discovery shall be attempted. For details, see
456 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
458 <xi:include href=
"version-info.xml" xpointer=
"v215"/>
463 <term><varname>systemd.image_policy=
</varname></term>
464 <term><varname>rd.systemd.image_policy=
</varname></term>
466 <listitem><para>When GPT-based partition auto-discovery is used, configures the image dissection
467 policy string to apply, as per
468 <citerefentry><refentrytitle>systemd.image-policy
</refentrytitle><manvolnum>7</manvolnum></citerefentry>. For
470 <citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
472 <xi:include href=
"version-info.xml" xpointer=
"v254"/></listitem>
476 <term><varname>systemd.default_timeout_start_sec=
</varname></term>
479 <para>Overrides the default start job timeout
<varname>DefaultTimeoutStartSec=
</varname> at
480 boot. For details, see
481 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
483 <xi:include href=
"version-info.xml" xpointer=
"v230"/>
488 <term><varname>systemd.default_device_timeout_sec=
</varname></term>
491 <para>Overrides the default device timeout
<varname>DefaultDeviceTimeoutSec=
</varname> at boot. For
493 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
495 <xi:include href=
"version-info.xml" xpointer=
"v254"/>
500 <term><varname>systemd.watchdog_device=
</varname></term>
503 <para>Overrides the watchdog device path
<varname>WatchdogDevice=
</varname>. For details, see
504 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
506 <xi:include href=
"version-info.xml" xpointer=
"v236"/>
511 <term><varname>systemd.watchdog_sec=
</varname></term>
514 <para>Overrides the watchdog timeout settings otherwise configured with
515 <varname>RuntimeWatchdog=
</varname>,
<varname>RebootWatchdog=
</varname> and
516 <varname>KExecWatchdogSec=
</varname>. Takes a time value (if no unit is specified, seconds is the
517 implicitly assumed time unit) or the special strings
<literal>off
</literal> or
518 <literal>default
</literal>. For details, see
519 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
521 <xi:include href=
"version-info.xml" xpointer=
"v250"/>
526 <term><varname>systemd.watchdog_pre_sec=
</varname></term>
529 <para>Overrides the watchdog pre-timeout settings otherwise configured with
530 <varname>RuntimeWatchdogPreSec=
</varname>. Takes a time value (if no unit is specified, seconds is the
531 implicitly assumed time unit) or the special strings
<literal>off
</literal> or
532 <literal>default
</literal>. For details, see
533 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
535 <xi:include href=
"version-info.xml" xpointer=
"v251"/>
540 <term><varname>systemd.watchdog_pretimeout_governor=
</varname></term>
543 <para>Overrides the watchdog pre-timeout settings otherwise configured with
544 <varname>RuntimeWatchdogPreGovernor=
</varname>. Takes a string value. For details, see
545 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
547 <xi:include href=
"version-info.xml" xpointer=
"v251"/>
552 <term><varname>systemd.cpu_affinity=
</varname></term>
555 <para>Overrides the CPU affinity mask for the service manager and the default for all child
556 processes it forks. This takes precedence over
<varname>CPUAffinity=
</varname>, see
557 <citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
560 <xi:include href=
"version-info.xml" xpointer=
"v245"/>
565 <term><varname>modules_load=
</varname></term>
566 <term><varname>rd.modules_load=
</varname></term>
569 <para>Load a specific kernel module early at boot. For
571 <citerefentry><refentrytitle>systemd-modules-load.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
573 <xi:include href=
"version-info.xml" xpointer=
"v187"/>
578 <term><varname>nameserver=
</varname></term>
579 <term><varname>domain=
</varname></term>
581 <listitem><para>Configures DNS server information and search domains, see
582 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
585 <xi:include href=
"version-info.xml" xpointer=
"v253"/></listitem>
589 <term><varname>resume=
</varname></term>
590 <term><varname>resumeflags=
</varname></term>
593 <para>Enables resume from hibernation using the specified
594 device and mount options. All
595 <citerefentry project='man-pages'
><refentrytitle>fstab
</refentrytitle><manvolnum>5</manvolnum></citerefentry>-like
596 paths are supported. For details, see
597 <citerefentry><refentrytitle>systemd-hibernate-resume-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
599 <xi:include href=
"version-info.xml" xpointer=
"v217"/>
604 <term><varname>systemd.firstboot=
</varname></term>
606 <listitem><para>Takes a boolean argument, defaults to on. If off,
607 <citerefentry><refentrytitle>systemd-firstboot.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
609 <citerefentry><refentrytitle>systemd-homed-firstboot.service
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
610 will not query the user for basic system settings, even if the system boots up for the first time and
611 the relevant settings are not initialized yet. Not to be confused with
612 <varname>systemd.condition_first_boot=
</varname> (see below), which overrides the result of the
613 <varname>ConditionFirstBoot=
</varname> unit file condition, and thus controls more than just
614 <filename>systemd-firstboot.service
</filename> behaviour.
</para>
616 <xi:include href=
"version-info.xml" xpointer=
"v233"/></listitem>
620 <term><varname>systemd.condition_needs_update=
</varname></term>
622 <listitem><para>Takes a boolean argument. If specified, overrides the result of
623 <varname>ConditionNeedsUpdate=
</varname> unit condition checks. See
624 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
627 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
631 <term><varname>systemd.condition_first_boot=
</varname></term>
633 <listitem><para>Takes a boolean argument. If specified, overrides the result of
634 <varname>ConditionFirstBoot=
</varname> unit condition checks. See
635 <citerefentry><refentrytitle>systemd.unit
</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
636 details. Not to be confused with
<varname>systemd.firstboot=
</varname> which only controls behaviour
637 of the
<filename>systemd-firstboot.service
</filename> system service but has no effect on the
638 condition check (see above).
</para>
640 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
644 <term><varname>systemd.clock_usec=
</varname></term>
646 <listitem><para>Takes a decimal, numeric timestamp in μs since January
1st
1970,
00:
00am, to set the
647 system clock to. The system time is set to the specified timestamp early during boot. It is not
648 propagated to the hardware clock (RTC).
</para>
650 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
654 <term><varname>systemd.random_seed=
</varname></term>
656 <listitem><para>Takes a base64 encoded random seed value to credit with full entropy to the kernel's
657 random pool during early service manager initialization. This option is useful in testing
658 environments where delays due to random pool initialization in entropy starved virtual machines shall
661 <para>Note that if this option is used the seed is accessible to unprivileged programs from
662 <filename>/proc/cmdline
</filename>. This option is hence a security risk when used outside of test
663 systems, since the (possibly) only seed used for initialization of the kernel's entropy pool might be
664 easily acquired by unprivileged programs.
</para>
666 <para>It is recommended to pass
512 bytes of randomized data (as that matches the Linux kernel pool
667 size), which may be generated with a command like the following:
</para>
669 <programlisting>dd if=/dev/urandom bs=
512 count=
1 status=none | base64 -w
0</programlisting>
671 <para>Again: do not use this option outside of testing environments, it's a security risk elsewhere,
672 as secret key material derived from the entropy pool can possibly be reconstructed by unprivileged
675 <xi:include href=
"version-info.xml" xpointer=
"v246"/>
680 <term><varname>systemd.hostname=
</varname></term>
682 <listitem><para>Accepts a hostname to set during early boot. If specified takes precedence over what
683 is set in
<filename>/etc/hostname
</filename>. Note that this does not bar later runtime changes to
684 the hostname, it simply controls the initial hostname set during early boot.
</para>
686 <xi:include href=
"version-info.xml" xpointer=
"v246"/></listitem>
690 <term><varname>systemd.tty.term.
<replaceable>tty
</replaceable>=
</varname></term>
691 <term><varname>systemd.tty.rows.
<replaceable>tty
</replaceable>=
</varname></term>
692 <term><varname>systemd.tty.columns.
<replaceable>tty
</replaceable>=
</varname></term>
694 <listitem><para>These arguments allow configuring default values for
<varname>$TERM
</varname>,
695 <varname>TTYRows=
</varname>, and
<varname>TTYColumns=
</varname> for tty
696 <replaceable>tty
</replaceable>. Additionally,
<varname>systemd.tty.term.console
</varname> will
697 configure the
<varname>$TERM
</varname> value used by
<command>systemd
</command> if not set explicitly
698 using
<varname>TERM
</varname> on the kernel command line. The tty name should be specified without
699 the
<filename>/dev/
</filename> prefix (e.g.
<literal>systemd.tty.rows.ttyS0=
80</literal>).
702 <xi:include href=
"version-info.xml" xpointer=
"v254"/></listitem>
706 <term><varname>systemd.battery_check=
</varname></term>
708 <listitem><para>Accepts a boolean argument. If false the boot-time battery charge check implemented
710 <citerefentry><refentrytitle>systemd-battery-check.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
713 <xi:include href=
"version-info.xml" xpointer=
"v254"/></listitem>
717 <term><varname>ifname=
</varname></term>
718 <term><varname>net.ifname_policy=
</varname></term>
720 <listitem><para>Controls interface naming policies, implemented by
721 <citerefentry><refentrytitle>systemd-network-generator.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
723 <xi:include href=
"version-info.xml" xpointer=
"v245"/></listitem>
727 <term><varname>systemd.tpm2_wait=
</varname></term>
729 <listitem><para>Controls whether to wait for a TPM2 device at boot, implemented by
730 <citerefentry><refentrytitle>systemd-tpm2-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
732 <xi:include href=
"version-info.xml" xpointer=
"v256"/></listitem>
739 <title>History
</title>
743 <term>systemd
252</term>
744 <listitem><para>Kernel command-line arguments
<varname>systemd.unified_cgroup_hierarchy
</varname>
745 and
<varname>systemd.legacy_systemd_cgroup_controller
</varname> were deprecated. Please switch to
746 the unified cgroup hierarchy.
</para>
748 <xi:include href=
"version-info.xml" xpointer=
"v252"/></listitem>
754 <title>See Also
</title>
755 <para><simplelist type=
"inline">
756 <member><citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
757 <member><citerefentry><refentrytitle>systemd-system.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
758 <member><citerefentry project='man-pages'
><refentrytitle>bootparam
</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
759 <member><citerefentry><refentrytitle>systemd.system-credentials
</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
760 <member><citerefentry><refentrytitle>smbios-type-
11</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
761 <member><citerefentry><refentrytitle>systemd-debug-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
762 <member><citerefentry><refentrytitle>systemd-fsck@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
763 <member><citerefentry><refentrytitle>systemd-quotacheck.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
764 <member><citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
765 <member><citerefentry><refentrytitle>systemd-vconsole-setup.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
766 <member><citerefentry><refentrytitle>systemd-udevd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
767 <member><citerefentry project='die-net'
><refentrytitle>plymouth
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
768 <member><citerefentry><refentrytitle>systemd-cryptsetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
769 <member><citerefentry><refentrytitle>systemd-veritysetup-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
770 <member><citerefentry><refentrytitle>systemd-fstab-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
771 <member><citerefentry><refentrytitle>systemd-getty-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
772 <member><citerefentry><refentrytitle>systemd-gpt-auto-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
773 <member><citerefentry><refentrytitle>systemd-volatile-root.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
774 <member><citerefentry><refentrytitle>systemd-modules-load.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
775 <member><citerefentry><refentrytitle>systemd-backlight@.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
776 <member><citerefentry><refentrytitle>systemd-rfkill.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
777 <member><citerefentry><refentrytitle>systemd-hibernate-resume-generator
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
778 <member><citerefentry><refentrytitle>systemd-firstboot.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
779 <member><citerefentry><refentrytitle>bootctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>