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c66e7bc7 | 1 | <?xml version='1.0'?> <!--*-nxml-*--> |
3a54a157 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
db9ecf05 | 4 | <!-- SPDX-License-Identifier: LGPL-2.1-or-later --> |
c66e7bc7 LP |
5 | |
6 | <refentry id="kernel-command-line"> | |
7 | ||
798d3a52 ZJS |
8 | <refentryinfo> |
9 | <title>kernel-command-line</title> | |
10 | <productname>systemd</productname> | |
798d3a52 ZJS |
11 | </refentryinfo> |
12 | ||
13 | <refmeta> | |
14 | <refentrytitle>kernel-command-line</refentrytitle> | |
15 | <manvolnum>7</manvolnum> | |
16 | </refmeta> | |
17 | ||
18 | <refnamediv> | |
19 | <refname>kernel-command-line</refname> | |
20 | <refpurpose>Kernel command line parameters</refpurpose> | |
21 | </refnamediv> | |
22 | ||
23 | <refsynopsisdiv> | |
24 | <para><filename>/proc/cmdline</filename></para> | |
25 | </refsynopsisdiv> | |
26 | ||
27 | <refsect1> | |
28 | <title>Description</title> | |
29 | ||
b66a6e1a ZJS |
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 | |
28f0aef4 ZJS |
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 | |
35 | command line.</para> | |
798d3a52 ZJS |
36 | |
37 | <para>For command line parameters understood by the kernel, please | |
ab1f7245 | 38 | see |
0e685823 | 39 | <ulink url="https://docs.kernel.org/admin-guide/kernel-parameters.html"><filename>kernel-parameters.html</filename></ulink> |
798d3a52 ZJS |
40 | and |
41 | <citerefentry project='man-pages'><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> | |
42 | ||
b66a6e1a | 43 | <para>For command line parameters understood by the initrd, see |
af105d03 | 44 | <citerefentry project='man-pages'><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
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45 | or the documentation of the specific initrd implementation of your |
46 | installation.</para> | |
47 | </refsect1> | |
48 | ||
49 | <refsect1> | |
50 | <title>Core OS Command Line Arguments</title> | |
51 | ||
52 | <variablelist class='kernel-commandline-options'> | |
53 | <varlistentry> | |
54 | <term><varname>systemd.unit=</varname></term> | |
55 | <term><varname>rd.systemd.unit=</varname></term> | |
770c4777 | 56 | <term><varname>systemd.dump_core</varname></term> |
c6885f5f | 57 | <term><varname>systemd.early_core_pattern=</varname></term> |
770c4777 ZJS |
58 | <term><varname>systemd.crash_chvt</varname></term> |
59 | <term><varname>systemd.crash_shell</varname></term> | |
60 | <term><varname>systemd.crash_reboot</varname></term> | |
61 | <term><varname>systemd.confirm_spawn</varname></term> | |
2a12e32e | 62 | <term><varname>systemd.service_watchdogs</varname></term> |
770c4777 | 63 | <term><varname>systemd.show_status</varname></term> |
36cf4507 | 64 | <term><varname>systemd.status_unit_format=</varname></term> |
798d3a52 ZJS |
65 | <term><varname>systemd.log_target=</varname></term> |
66 | <term><varname>systemd.log_level=</varname></term> | |
798d3a52 | 67 | <term><varname>systemd.log_location=</varname></term> |
770c4777 | 68 | <term><varname>systemd.log_color</varname></term> |
798d3a52 ZJS |
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> | |
ee48dbd5 | 72 | <term><varname>systemd.machine_id=</varname></term> |
72267a55 LP |
73 | <term><varname>systemd.set_credential=</varname></term> |
74 | <term><varname>systemd.import_credentials=</varname></term> | |
856bfaeb LB |
75 | <term><varname>systemd.reload_limit_interval_sec=</varname></term> |
76 | <term><varname>systemd.reload_limit_burst=</varname></term> | |
798d3a52 ZJS |
77 | <listitem> |
78 | <para>Parameters understood by the system and service | |
79 | manager to control system behavior. For details, see | |
80 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> | |
81 | </listitem> | |
82 | </varlistentry> | |
83 | ||
84 | <varlistentry> | |
85 | <term><varname>systemd.mask=</varname></term> | |
86 | <term><varname>systemd.wants=</varname></term> | |
1d84ad94 | 87 | <term><varname>systemd.debug_shell</varname></term> |
798d3a52 ZJS |
88 | <listitem> |
89 | <para>Additional parameters understood by | |
90 | <citerefentry><refentrytitle>systemd-debug-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
91 | to mask or start specific units at boot, or invoke a debug | |
92 | shell on tty9.</para> | |
93 | </listitem> | |
94 | </varlistentry> | |
95 | ||
565f3d91 LP |
96 | <varlistentry> |
97 | <term><varname>systemd.run=</varname></term> | |
98 | <term><varname>systemd.run_success_action=</varname></term> | |
99 | <term><varname>systemd.run_failure_action=</varname></term> | |
100 | <listitem> | |
101 | <para>Additional parameters understood by | |
102 | <citerefentry><refentrytitle>systemd-run-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, to | |
103 | run a command line specified on the kernel command line as system service after booting up.</para> | |
104 | </listitem> | |
105 | </varlistentry> | |
106 | ||
c6885f5f FB |
107 | <varlistentry> |
108 | <term><varname>systemd.early_core_pattern=</varname></term> | |
109 | <listitem> | |
110 | <para>During early boot, the generation of core dump files is disabled until a core dump handler (if any) | |
11fcfc53 | 111 | takes over. This parameter allows specifying an absolute path where core dump files should be stored until |
c6885f5f | 112 | a handler is installed. The path should be absolute and may contain specifiers, see |
b7a47345 | 113 | <citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.</para> |
c6885f5f FB |
114 | </listitem> |
115 | </varlistentry> | |
116 | ||
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117 | <varlistentry> |
118 | <term><varname>systemd.restore_state=</varname></term> | |
119 | <listitem> | |
120 | <para>This parameter is understood by several system tools | |
121 | to control whether or not they should restore system state | |
122 | from the previous boot. For details, see | |
123 | <citerefentry><refentrytitle>systemd-backlight@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
124 | and | |
af105d03 | 125 | <citerefentry><refentrytitle>systemd-rfkill.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. |
798d3a52 ZJS |
126 | </para> |
127 | </listitem> | |
128 | </varlistentry> | |
129 | ||
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130 | <varlistentry> |
131 | <term><varname>systemd.volatile=</varname></term> | |
132 | <listitem> | |
133 | <para>This parameter controls whether the system shall boot up in volatile mode. Takes a boolean argument, or | |
134 | the special value <literal>state</literal>. If false (the default), normal boot mode is selected, the root | |
3b121157 | 135 | directory and <filename>/var/</filename> are mounted as specified on the kernel command line or |
91214a37 LP |
136 | <filename>/etc/fstab</filename>, or otherwise configured. If true, full state-less boot mode is selected. In |
137 | this case the root directory is mounted as volatile memory file system (<literal>tmpfs</literal>), and only | |
3b121157 | 138 | <filename>/usr/</filename> is mounted from the file system configured as root device, in read-only mode. This |
91214a37 | 139 | enables fully state-less boots were the vendor-supplied OS is used as shipped, with only default |
3b121157 | 140 | configuration and no stored state in effect, as <filename>/etc/</filename> and <filename>/var/</filename> (as |
91214a37 | 141 | well as all other resources shipped in the root file system) are reset at boot and lost on shutdown. If this |
13070a70 | 142 | setting is set to <literal>state</literal> the root file system is mounted read-only, however |
3b121157 | 143 | <filename>/var/</filename> is mounted as a volatile memory file system (<literal>tmpfs</literal>), so that the |
13070a70 LP |
144 | system boots up with the normal configuration applied, but all state reset at boot and lost at shutdown. If |
145 | this setting is set to <literal>overlay</literal> the root file system is set up as | |
146 | <literal>overlayfs</literal> mount combining the read-only root directory with a writable | |
147 | <literal>tmpfs</literal>, so that no modifications are made to disk, but the file system may be modified | |
148 | nonetheless with all changes being lost at reboot. For details, see | |
91214a37 LP |
149 | <citerefentry><refentrytitle>systemd-volatile-root.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
150 | and | |
151 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
152 | </listitem> | |
153 | </varlistentry> | |
154 | ||
798d3a52 ZJS |
155 | <varlistentry> |
156 | <term><varname>quiet</varname></term> | |
157 | <listitem> | |
158 | <para>Parameter understood by both the kernel and the system | |
159 | and service manager to control console log verbosity. For | |
160 | details, see | |
161 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> | |
162 | </listitem> | |
163 | </varlistentry> | |
164 | ||
165 | <varlistentry> | |
166 | <term><varname>debug</varname></term> | |
167 | <listitem> | |
168 | <para>Parameter understood by both the kernel and the system | |
169 | and service manager to control console log verbosity. For | |
170 | details, see | |
171 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> | |
172 | </listitem> | |
173 | </varlistentry> | |
174 | ||
175 | <varlistentry> | |
176 | <term><varname>-b</varname></term> | |
dcd61450 | 177 | <term><varname>rd.emergency</varname></term> |
798d3a52 | 178 | <term><varname>emergency</varname></term> |
dcd61450 | 179 | <term><varname>rd.rescue</varname></term> |
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180 | <term><varname>rescue</varname></term> |
181 | <term><varname>single</varname></term> | |
182 | <term><varname>s</varname></term> | |
183 | <term><varname>S</varname></term> | |
184 | <term><varname>1</varname></term> | |
185 | <term><varname>2</varname></term> | |
186 | <term><varname>3</varname></term> | |
187 | <term><varname>4</varname></term> | |
188 | <term><varname>5</varname></term> | |
189 | <listitem> | |
190 | <para>Parameters understood by the system and service | |
dcd61450 | 191 | manager, as compatibility and convenience options. For details, see |
798d3a52 ZJS |
192 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> |
193 | </listitem> | |
194 | </varlistentry> | |
195 | ||
196 | <varlistentry> | |
197 | <term><varname>locale.LANG=</varname></term> | |
198 | <term><varname>locale.LANGUAGE=</varname></term> | |
199 | <term><varname>locale.LC_CTYPE=</varname></term> | |
200 | <term><varname>locale.LC_NUMERIC=</varname></term> | |
201 | <term><varname>locale.LC_TIME=</varname></term> | |
202 | <term><varname>locale.LC_COLLATE=</varname></term> | |
203 | <term><varname>locale.LC_MONETARY=</varname></term> | |
204 | <term><varname>locale.LC_MESSAGES=</varname></term> | |
205 | <term><varname>locale.LC_PAPER=</varname></term> | |
206 | <term><varname>locale.LC_NAME=</varname></term> | |
207 | <term><varname>locale.LC_ADDRESS=</varname></term> | |
208 | <term><varname>locale.LC_TELEPHONE=</varname></term> | |
209 | <term><varname>locale.LC_MEASUREMENT=</varname></term> | |
210 | <term><varname>locale.LC_IDENTIFICATION=</varname></term> | |
211 | <listitem> | |
212 | <para>Parameters understood by the system and service | |
213 | manager to control locale and language settings. For | |
214 | details, see | |
215 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> | |
216 | </listitem> | |
217 | </varlistentry> | |
218 | ||
219 | <varlistentry> | |
220 | <term><varname>fsck.mode=</varname></term> | |
221 | <term><varname>fsck.repair=</varname></term> | |
222 | ||
223 | <listitem> | |
224 | <para>Parameters understood by the file system checker | |
225 | services. For details, see | |
226 | <citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
227 | </listitem> | |
228 | </varlistentry> | |
229 | ||
230 | <varlistentry> | |
231 | <term><varname>quotacheck.mode=</varname></term> | |
232 | ||
233 | <listitem> | |
234 | <para>Parameter understood by the file quota checker | |
235 | service. For details, see | |
236 | <citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
237 | </listitem> | |
238 | </varlistentry> | |
239 | ||
240 | <varlistentry> | |
241 | <term><varname>systemd.journald.forward_to_syslog=</varname></term> | |
242 | <term><varname>systemd.journald.forward_to_kmsg=</varname></term> | |
243 | <term><varname>systemd.journald.forward_to_console=</varname></term> | |
244 | <term><varname>systemd.journald.forward_to_wall=</varname></term> | |
245 | ||
246 | <listitem> | |
247 | <para>Parameters understood by the journal service. For | |
248 | details, see | |
249 | <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
250 | </listitem> | |
251 | </varlistentry> | |
252 | ||
253 | <varlistentry> | |
254 | <term><varname>vconsole.keymap=</varname></term> | |
72ccee50 | 255 | <term><varname>vconsole.keymap_toggle=</varname></term> |
798d3a52 | 256 | <term><varname>vconsole.font=</varname></term> |
72ccee50 ZJS |
257 | <term><varname>vconsole.font_map=</varname></term> |
258 | <term><varname>vconsole.font_unimap=</varname></term> | |
798d3a52 ZJS |
259 | |
260 | <listitem> | |
72ccee50 ZJS |
261 | <para>Parameters understood by the virtual console setup logic. For details, see |
262 | <citerefentry><refentrytitle>vconsole.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
798d3a52 ZJS |
263 | </listitem> |
264 | </varlistentry> | |
265 | ||
266 | <varlistentry> | |
64a3494c FB |
267 | <term><varname>udev.log_level=</varname></term> |
268 | <term><varname>rd.udev.log_level=</varname></term> | |
1d84ad94 LP |
269 | <term><varname>udev.children_max=</varname></term> |
270 | <term><varname>rd.udev.children_max=</varname></term> | |
271 | <term><varname>udev.exec_delay=</varname></term> | |
272 | <term><varname>rd.udev.exec_delay=</varname></term> | |
273 | <term><varname>udev.event_timeout=</varname></term> | |
274 | <term><varname>rd.udev.event_timeout=</varname></term> | |
e2099267 MS |
275 | <term><varname>udev.timeout_signal=</varname></term> |
276 | <term><varname>rd.udev.timeout_signal=</varname></term> | |
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277 | <term><varname>udev.blockdev_read_only</varname></term> |
278 | <term><varname>rd.udev.blockdev_read_only</varname></term> | |
798d3a52 | 279 | <term><varname>net.ifnames=</varname></term> |
f7e81fd9 | 280 | <term><varname>net.naming-scheme=</varname></term> |
798d3a52 ZJS |
281 | |
282 | <listitem> | |
283 | <para>Parameters understood by the device event managing | |
284 | daemon. For details, see | |
285 | <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
286 | </listitem> | |
287 | </varlistentry> | |
288 | ||
289 | <varlistentry> | |
290 | <term><varname>plymouth.enable=</varname></term> | |
291 | ||
292 | <listitem> | |
293 | <para>May be used to disable the Plymouth boot splash. For | |
294 | details, see | |
295 | <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
296 | </listitem> | |
297 | </varlistentry> | |
298 | ||
299 | <varlistentry> | |
300 | <term><varname>luks=</varname></term> | |
301 | <term><varname>rd.luks=</varname></term> | |
302 | <term><varname>luks.crypttab=</varname></term> | |
303 | <term><varname>rd.luks.crypttab=</varname></term> | |
304 | <term><varname>luks.name=</varname></term> | |
305 | <term><varname>rd.luks.name=</varname></term> | |
306 | <term><varname>luks.uuid=</varname></term> | |
307 | <term><varname>rd.luks.uuid=</varname></term> | |
308 | <term><varname>luks.options=</varname></term> | |
309 | <term><varname>rd.luks.options=</varname></term> | |
310 | <term><varname>luks.key=</varname></term> | |
311 | <term><varname>rd.luks.key=</varname></term> | |
312 | ||
313 | <listitem> | |
314 | <para>Configures the LUKS full-disk encryption logic at | |
315 | boot. For details, see | |
316 | <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
317 | </listitem> | |
318 | </varlistentry> | |
319 | ||
320 | <varlistentry> | |
321 | <term><varname>fstab=</varname></term> | |
322 | <term><varname>rd.fstab=</varname></term> | |
323 | ||
324 | <listitem> | |
325 | <para>Configures the <filename>/etc/fstab</filename> logic | |
326 | at boot. For details, see | |
327 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
328 | </listitem> | |
329 | </varlistentry> | |
330 | ||
331 | <varlistentry> | |
332 | <term><varname>root=</varname></term> | |
333 | <term><varname>rootfstype=</varname></term> | |
d6a12e7c | 334 | <term><varname>rootflags=</varname></term> |
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335 | <term><varname>ro</varname></term> |
336 | <term><varname>rw</varname></term> | |
337 | ||
338 | <listitem> | |
339 | <para>Configures the root file system and its file system | |
340 | type and mount options, as well as whether it shall be | |
17ec531f | 341 | mounted read-only or read-write initially. For details, |
798d3a52 ZJS |
342 | see |
343 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
344 | </listitem> | |
345 | </varlistentry> | |
346 | ||
6dfcea32 TH |
347 | <varlistentry> |
348 | <term><varname>mount.usr=</varname></term> | |
349 | <term><varname>mount.usrfstype=</varname></term> | |
350 | <term><varname>mount.usrflags=</varname></term> | |
351 | ||
352 | <listitem> | |
353 | <para>Configures the /usr file system (if required) and | |
354 | its file system type and mount options. For details, see | |
355 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
356 | </listitem> | |
357 | </varlistentry> | |
358 | ||
2f3dfc6f | 359 | <varlistentry> |
08b04ec7 GP |
360 | <term><varname>veritytab=</varname></term> |
361 | <term><varname>rd.veritytab=</varname></term> | |
2f3dfc6f LP |
362 | <term><varname>roothash=</varname></term> |
363 | <term><varname>systemd.verity=</varname></term> | |
364 | <term><varname>rd.systemd.verity=</varname></term> | |
365 | <term><varname>systemd.verity_root_data=</varname></term> | |
366 | <term><varname>systemd.verity_root_hash=</varname></term> | |
0141102f | 367 | <term><varname>systemd.verity.root_options=</varname></term> |
e5196eee MB |
368 | <term><varname>usrhash=</varname></term> |
369 | <term><varname>systemd.verity_usr_data=</varname></term> | |
370 | <term><varname>systemd.verity_usr_hash=</varname></term> | |
371 | <term><varname>systemd.verity_usr_options=</varname></term> | |
2f3dfc6f | 372 | <listitem> |
e5196eee | 373 | <para>Configures the integrity protection root hash for the root and <filename>/usr</filename> file systems, and other related |
2f3dfc6f LP |
374 | parameters. For details, see |
375 | <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
376 | </listitem> | |
377 | </varlistentry> | |
378 | ||
21d00e52 LB |
379 | <varlistentry> |
380 | <term><varname>systemd.getty_auto=</varname></term> | |
381 | ||
382 | <listitem> | |
383 | <para>Configures whether the <filename>serial-getty@.service</filename> will run. | |
384 | For details, see | |
385 | <citerefentry><refentrytitle>systemd-getty-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
386 | </listitem> | |
387 | </varlistentry> | |
388 | ||
798d3a52 ZJS |
389 | <varlistentry> |
390 | <term><varname>systemd.gpt_auto=</varname></term> | |
391 | <term><varname>rd.systemd.gpt_auto=</varname></term> | |
392 | ||
393 | <listitem> | |
394 | <para>Configures whether GPT based partition auto-discovery | |
395 | shall be attempted. For details, see | |
396 | <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
397 | </listitem> | |
398 | </varlistentry> | |
399 | ||
959718c6 TB |
400 | <varlistentry> |
401 | <term><varname>systemd.default_timeout_start_sec=</varname></term> | |
402 | ||
403 | <listitem> | |
ba669952 | 404 | <para>Overrides the default start job timeout <varname>DefaultTimeoutStartSec=</varname> at |
9c5ea4b1 LP |
405 | boot. For details, see |
406 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
c75396c3 EJ |
407 | </listitem> |
408 | </varlistentry> | |
409 | ||
410 | <varlistentry> | |
411 | <term><varname>systemd.watchdog_device=</varname></term> | |
412 | ||
413 | <listitem> | |
ba669952 | 414 | <para>Overrides the watchdog device path <varname>WatchdogDevice=</varname>. For details, see |
9c5ea4b1 LP |
415 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> |
416 | </listitem> | |
417 | </varlistentry> | |
418 | ||
419 | <varlistentry> | |
420 | <term><varname>systemd.watchdog_sec=</varname></term> | |
421 | ||
422 | <listitem> | |
ba669952 | 423 | <para>Overrides the watchdog timeout settings otherwise configured with |
9c5ea4b1 LP |
424 | <varname>RuntimeWatchdog=</varname>, <varname>RebootWatchdog=</varname> and |
425 | <varname>KExecWatchdogSec=</varname>. Takes a time value (if no unit is specified, seconds is the | |
426 | implicitly assumed time unit) or the special strings <literal>off</literal> or | |
427 | <literal>default</literal>. For details, see | |
c75396c3 | 428 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> |
959718c6 TB |
429 | </listitem> |
430 | </varlistentry> | |
431 | ||
5717062e CK |
432 | <varlistentry> |
433 | <term><varname>systemd.watchdog_pre_sec=</varname></term> | |
434 | ||
435 | <listitem> | |
436 | <para>Overrides the watchdog pre-timeout settings otherwise configured with | |
437 | <varname>RuntimeWatchdogPreSec=</varname>. Takes a time value (if no unit is specified, seconds is the | |
438 | implicitly assumed time unit) or the special strings <literal>off</literal> or | |
439 | <literal>default</literal>. For details, see | |
440 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
441 | </listitem> | |
442 | </varlistentry> | |
443 | ||
aff3a9e1 LB |
444 | <varlistentry> |
445 | <term><varname>systemd.watchdog_pretimeout_governor=</varname></term> | |
446 | ||
447 | <listitem> | |
448 | <para>Overrides the watchdog pre-timeout settings otherwise configured with | |
449 | <varname>RuntimeWatchdogPreGovernor=</varname>. Takes a string value. For details, see | |
450 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
451 | </listitem> | |
452 | </varlistentry> | |
453 | ||
68d58f38 LP |
454 | <varlistentry> |
455 | <term><varname>systemd.cpu_affinity=</varname></term> | |
456 | ||
457 | <listitem> | |
458 | <para>Overrides the CPU affinity mask for the service manager and the default for all child | |
459 | processes it forks. This takes precedence over <varname>CPUAffinity=</varname>, see | |
460 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
461 | for details.</para> | |
462 | </listitem> | |
463 | </varlistentry> | |
464 | ||
798d3a52 | 465 | <varlistentry> |
1d84ad94 LP |
466 | <term><varname>modules_load=</varname></term> |
467 | <term><varname>rd.modules_load=</varname></term> | |
798d3a52 ZJS |
468 | |
469 | <listitem> | |
470 | <para>Load a specific kernel module early at boot. For | |
471 | details, see | |
472 | <citerefentry><refentrytitle>systemd-modules-load.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
473 | </listitem> | |
474 | </varlistentry> | |
475 | ||
476 | <varlistentry> | |
477 | <term><varname>resume=</varname></term> | |
8b6805a2 | 478 | <term><varname>resumeflags=</varname></term> |
798d3a52 ZJS |
479 | |
480 | <listitem> | |
481 | <para>Enables resume from hibernation using the specified | |
8b6805a2 | 482 | device and mount options. All |
3ba3a79d | 483 | <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>-like |
798d3a52 ZJS |
484 | paths are supported. For details, see |
485 | <citerefentry><refentrytitle>systemd-hibernate-resume-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
486 | </listitem> | |
487 | </varlistentry> | |
f582cbca LP |
488 | |
489 | <varlistentry> | |
490 | <term><varname>systemd.firstboot=</varname></term> | |
491 | ||
492 | <listitem><para>Takes a boolean argument, defaults to on. If off, | |
493 | <citerefentry><refentrytitle>systemd-firstboot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
814872e9 LP |
494 | will not query the user for basic system settings, even if the system boots up for the first time and |
495 | the relevant settings are not initialized yet. Not to be confused with | |
496 | <varname>systemd.condition-first-boot=</varname> (see below), which overrides the result of the | |
497 | <varname>ConditionFirstBoot=</varname> unit file condition, and thus controls more than just | |
498 | <filename>systemd-firstboot.service</filename> behaviour.</para></listitem> | |
f582cbca | 499 | </varlistentry> |
f8b4ae29 LP |
500 | |
501 | <varlistentry> | |
502 | <term><varname>systemd.condition-needs-update=</varname></term> | |
503 | ||
504 | <listitem><para>Takes a boolean argument. If specified, overrides the result of | |
505 | <varname>ConditionNeedsUpdate=</varname> unit condition checks. See | |
506 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
507 | details.</para></listitem> | |
508 | </varlistentry> | |
814872e9 LP |
509 | |
510 | <varlistentry> | |
511 | <term><varname>systemd.condition-first-boot=</varname></term> | |
512 | ||
513 | <listitem><para>Takes a boolean argument. If specified, overrides the result of | |
514 | <varname>ConditionFirstBoot=</varname> unit condition checks. See | |
515 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
516 | details. Not to be confused with <varname>systemd.firstboot=</varname> which only controls behaviour | |
517 | of the <filename>systemd-firstboot.service</filename> system service but has no effect on the | |
518 | condition check (see above).</para></listitem> | |
519 | </varlistentry> | |
3753325b LP |
520 | |
521 | <varlistentry> | |
522 | <term><varname>systemd.clock-usec=</varname></term> | |
523 | ||
524 | <listitem><para>Takes a decimal, numeric timestamp in µs since January 1st 1970, 00:00am, to set the | |
18d9cee0 LP |
525 | system clock to. The system time is set to the specified timestamp early during boot. It is not |
526 | propagated to the hardware clock (RTC).</para></listitem> | |
527 | </varlistentry> | |
528 | ||
529 | <varlistentry> | |
530 | <term><varname>systemd.random-seed=</varname></term> | |
531 | ||
532 | <listitem><para>Takes a base64 encoded random seed value to credit with full entropy to the kernel's | |
533 | random pool during early service manager initialization. This option is useful in testing | |
534 | environments where delays due to random pool initialization in entropy starved virtual machines shall | |
535 | be avoided.</para> | |
536 | ||
537 | <para>Note that if this option is used the seed is accessible to unprivileged programs from | |
538 | <filename>/proc/cmdline</filename>. This option is hence a security risk when used outside of test | |
539 | systems, since the (possibly) only seed used for initialization of the kernel's entropy pool might be | |
540 | easily acquired by unprivileged programs.</para> | |
541 | ||
542 | <para>It is recommended to pass 512 bytes of randomized data (as that matches the Linux kernel pool | |
543 | size), which may be generated with a command like the following:</para> | |
544 | ||
545 | <programlisting>dd if=/dev/urandom bs=512 count=1 status=none | base64 -w 0</programlisting> | |
546 | ||
547 | <para>Again: do not use this option outside of testing environments, it's a security risk elsewhere, | |
548 | as secret key material derived from the entropy pool can possibly be reconstructed by unprivileged | |
549 | programs.</para> | |
550 | </listitem> | |
3753325b | 551 | </varlistentry> |
34293dfa LP |
552 | |
553 | <varlistentry> | |
554 | <term><varname>systemd.hostname=</varname></term> | |
555 | ||
556 | <listitem><para>Accepts a hostname to set during early boot. If specified takes precedence over what | |
557 | is set in <filename>/etc/hostname</filename>. Note that this does not bar later runtime changes to | |
558 | the hostname, it simply controls the initial hostname set during early boot.</para></listitem> | |
559 | </varlistentry> | |
798d3a52 | 560 | </variablelist> |
7a9e0bd0 | 561 | </refsect1> |
798d3a52 | 562 | |
7a9e0bd0 ZJS |
563 | <refsect1> |
564 | <title>History</title> | |
565 | ||
566 | <variablelist> | |
567 | <varlistentry> | |
568 | <term>systemd 252</term> | |
569 | <listitem><para>Kernel command-line arguments <varname>systemd.unified_cgroup_hierarchy</varname> | |
570 | and <varname>systemd.legacy_systemd_cgroup_controller</varname> were deprecated. Please switch to | |
571 | the unified cgroup hierarchy.</para></listitem> | |
572 | </varlistentry> | |
573 | </variablelist> | |
798d3a52 ZJS |
574 | </refsect1> |
575 | ||
576 | <refsect1> | |
577 | <title>See Also</title> | |
578 | <para> | |
579 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
d1698b82 | 580 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
798d3a52 | 581 | <citerefentry project='man-pages'><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
af105d03 | 582 | <citerefentry project='man-pages'><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
798d3a52 ZJS |
583 | <citerefentry><refentrytitle>systemd-debug-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
584 | <citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
585 | <citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
586 | <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
587 | <citerefentry><refentrytitle>systemd-vconsole-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
588 | <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
589 | <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
590 | <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
2f3dfc6f | 591 | <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
798d3a52 | 592 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
21d00e52 | 593 | <citerefentry><refentrytitle>systemd-getty-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
798d3a52 | 594 | <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
91214a37 | 595 | <citerefentry><refentrytitle>systemd-volatile-root.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
798d3a52 ZJS |
596 | <citerefentry><refentrytitle>systemd-modules-load.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
597 | <citerefentry><refentrytitle>systemd-backlight@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
af105d03 | 598 | <citerefentry><refentrytitle>systemd-rfkill.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
f582cbca | 599 | <citerefentry><refentrytitle>systemd-hibernate-resume-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
4e5aa791 ZJS |
600 | <citerefentry><refentrytitle>systemd-firstboot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
601 | <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
798d3a52 ZJS |
602 | </para> |
603 | </refsect1> | |
c66e7bc7 LP |
604 | |
605 | </refentry> |