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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 --> |
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5 | |
6 | <refentry id="kernel-command-line"> | |
7 | ||
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8 | <refentryinfo> |
9 | <title>kernel-command-line</title> | |
10 | <productname>systemd</productname> | |
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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 | ||
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30 | <para>The kernel, the initial RAM disk (initrd) and basic userspace functionality may be configured at |
31 | boot via 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 | |
35 | command line.</para> | |
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36 | |
37 | <para>For command line parameters understood by the kernel, please | |
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38 | see |
39 | <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html"><filename>kernel-parameters.html</filename></ulink> | |
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40 | and |
41 | <citerefentry project='man-pages'><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> | |
42 | ||
43 | <para>For command line parameters understood by the initial RAM | |
44 | disk, please see | |
af105d03 | 45 | <citerefentry project='man-pages'><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
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46 | or the documentation of the specific initrd implementation of your |
47 | installation.</para> | |
48 | </refsect1> | |
49 | ||
50 | <refsect1> | |
51 | <title>Core OS Command Line Arguments</title> | |
52 | ||
53 | <variablelist class='kernel-commandline-options'> | |
54 | <varlistentry> | |
55 | <term><varname>systemd.unit=</varname></term> | |
56 | <term><varname>rd.systemd.unit=</varname></term> | |
770c4777 | 57 | <term><varname>systemd.dump_core</varname></term> |
c6885f5f | 58 | <term><varname>systemd.early_core_pattern=</varname></term> |
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59 | <term><varname>systemd.crash_chvt</varname></term> |
60 | <term><varname>systemd.crash_shell</varname></term> | |
61 | <term><varname>systemd.crash_reboot</varname></term> | |
62 | <term><varname>systemd.confirm_spawn</varname></term> | |
2a12e32e | 63 | <term><varname>systemd.service_watchdogs</varname></term> |
770c4777 | 64 | <term><varname>systemd.show_status</varname></term> |
36cf4507 | 65 | <term><varname>systemd.status_unit_format=</varname></term> |
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66 | <term><varname>systemd.log_target=</varname></term> |
67 | <term><varname>systemd.log_level=</varname></term> | |
798d3a52 | 68 | <term><varname>systemd.log_location=</varname></term> |
770c4777 | 69 | <term><varname>systemd.log_color</varname></term> |
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70 | <term><varname>systemd.default_standard_output=</varname></term> |
71 | <term><varname>systemd.default_standard_error=</varname></term> | |
72 | <term><varname>systemd.setenv=</varname></term> | |
ee48dbd5 | 73 | <term><varname>systemd.machine_id=</varname></term> |
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74 | <term><varname>systemd.unified_cgroup_hierarchy</varname></term> |
75 | <term><varname>systemd.legacy_systemd_cgroup_controller</varname></term> | |
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76 | <listitem> |
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> | |
80 | </listitem> | |
81 | </varlistentry> | |
82 | ||
83 | <varlistentry> | |
84 | <term><varname>systemd.mask=</varname></term> | |
85 | <term><varname>systemd.wants=</varname></term> | |
1d84ad94 | 86 | <term><varname>systemd.debug_shell</varname></term> |
798d3a52 ZJS |
87 | <listitem> |
88 | <para>Additional parameters understood by | |
89 | <citerefentry><refentrytitle>systemd-debug-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
90 | to mask or start specific units at boot, or invoke a debug | |
91 | shell on tty9.</para> | |
92 | </listitem> | |
93 | </varlistentry> | |
94 | ||
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95 | <varlistentry> |
96 | <term><varname>systemd.run=</varname></term> | |
97 | <term><varname>systemd.run_success_action=</varname></term> | |
98 | <term><varname>systemd.run_failure_action=</varname></term> | |
99 | <listitem> | |
100 | <para>Additional parameters understood by | |
101 | <citerefentry><refentrytitle>systemd-run-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, to | |
102 | run a command line specified on the kernel command line as system service after booting up.</para> | |
103 | </listitem> | |
104 | </varlistentry> | |
105 | ||
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106 | <varlistentry> |
107 | <term><varname>systemd.early_core_pattern=</varname></term> | |
108 | <listitem> | |
109 | <para>During early boot, the generation of core dump files is disabled until a core dump handler (if any) | |
11fcfc53 | 110 | takes over. This parameter allows specifying an absolute path where core dump files should be stored until |
c6885f5f | 111 | a handler is installed. The path should be absolute and may contain specifiers, see |
b7a47345 | 112 | <citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.</para> |
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113 | </listitem> |
114 | </varlistentry> | |
115 | ||
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116 | <varlistentry> |
117 | <term><varname>systemd.restore_state=</varname></term> | |
118 | <listitem> | |
119 | <para>This parameter is understood by several system tools | |
120 | to control whether or not they should restore system state | |
121 | from the previous boot. For details, see | |
122 | <citerefentry><refentrytitle>systemd-backlight@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
123 | and | |
af105d03 | 124 | <citerefentry><refentrytitle>systemd-rfkill.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. |
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125 | </para> |
126 | </listitem> | |
127 | </varlistentry> | |
128 | ||
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129 | <varlistentry> |
130 | <term><varname>systemd.volatile=</varname></term> | |
131 | <listitem> | |
132 | <para>This parameter controls whether the system shall boot up in volatile mode. Takes a boolean argument, or | |
133 | the special value <literal>state</literal>. If false (the default), normal boot mode is selected, the root | |
3b121157 | 134 | directory and <filename>/var/</filename> are mounted as specified on the kernel command line or |
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135 | <filename>/etc/fstab</filename>, or otherwise configured. If true, full state-less boot mode is selected. In |
136 | this case the root directory is mounted as volatile memory file system (<literal>tmpfs</literal>), and only | |
3b121157 | 137 | <filename>/usr/</filename> is mounted from the file system configured as root device, in read-only mode. This |
91214a37 | 138 | enables fully state-less boots were the vendor-supplied OS is used as shipped, with only default |
3b121157 | 139 | configuration and no stored state in effect, as <filename>/etc/</filename> and <filename>/var/</filename> (as |
91214a37 | 140 | well as all other resources shipped in the root file system) are reset at boot and lost on shutdown. If this |
13070a70 | 141 | setting is set to <literal>state</literal> the root file system is mounted read-only, however |
3b121157 | 142 | <filename>/var/</filename> is mounted as a volatile memory file system (<literal>tmpfs</literal>), so that the |
13070a70 LP |
143 | system boots up with the normal configuration applied, but all state reset at boot and lost at shutdown. If |
144 | this setting is set to <literal>overlay</literal> the root file system is set up as | |
145 | <literal>overlayfs</literal> mount combining the read-only root directory with a writable | |
146 | <literal>tmpfs</literal>, so that no modifications are made to disk, but the file system may be modified | |
147 | nonetheless with all changes being lost at reboot. For details, see | |
91214a37 LP |
148 | <citerefentry><refentrytitle>systemd-volatile-root.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
149 | and | |
150 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
151 | </listitem> | |
152 | </varlistentry> | |
153 | ||
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154 | <varlistentry> |
155 | <term><varname>quiet</varname></term> | |
156 | <listitem> | |
157 | <para>Parameter understood by both the kernel and the system | |
158 | and service manager to control console log verbosity. For | |
159 | details, see | |
160 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> | |
161 | </listitem> | |
162 | </varlistentry> | |
163 | ||
164 | <varlistentry> | |
165 | <term><varname>debug</varname></term> | |
166 | <listitem> | |
167 | <para>Parameter understood by both the kernel and the system | |
168 | and service manager to control console log verbosity. For | |
169 | details, see | |
170 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> | |
171 | </listitem> | |
172 | </varlistentry> | |
173 | ||
174 | <varlistentry> | |
175 | <term><varname>-b</varname></term> | |
dcd61450 | 176 | <term><varname>rd.emergency</varname></term> |
798d3a52 | 177 | <term><varname>emergency</varname></term> |
dcd61450 | 178 | <term><varname>rd.rescue</varname></term> |
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179 | <term><varname>rescue</varname></term> |
180 | <term><varname>single</varname></term> | |
181 | <term><varname>s</varname></term> | |
182 | <term><varname>S</varname></term> | |
183 | <term><varname>1</varname></term> | |
184 | <term><varname>2</varname></term> | |
185 | <term><varname>3</varname></term> | |
186 | <term><varname>4</varname></term> | |
187 | <term><varname>5</varname></term> | |
188 | <listitem> | |
189 | <para>Parameters understood by the system and service | |
dcd61450 | 190 | manager, as compatibility and convenience options. For details, see |
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191 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> |
192 | </listitem> | |
193 | </varlistentry> | |
194 | ||
195 | <varlistentry> | |
196 | <term><varname>locale.LANG=</varname></term> | |
197 | <term><varname>locale.LANGUAGE=</varname></term> | |
198 | <term><varname>locale.LC_CTYPE=</varname></term> | |
199 | <term><varname>locale.LC_NUMERIC=</varname></term> | |
200 | <term><varname>locale.LC_TIME=</varname></term> | |
201 | <term><varname>locale.LC_COLLATE=</varname></term> | |
202 | <term><varname>locale.LC_MONETARY=</varname></term> | |
203 | <term><varname>locale.LC_MESSAGES=</varname></term> | |
204 | <term><varname>locale.LC_PAPER=</varname></term> | |
205 | <term><varname>locale.LC_NAME=</varname></term> | |
206 | <term><varname>locale.LC_ADDRESS=</varname></term> | |
207 | <term><varname>locale.LC_TELEPHONE=</varname></term> | |
208 | <term><varname>locale.LC_MEASUREMENT=</varname></term> | |
209 | <term><varname>locale.LC_IDENTIFICATION=</varname></term> | |
210 | <listitem> | |
211 | <para>Parameters understood by the system and service | |
212 | manager to control locale and language settings. For | |
213 | details, see | |
214 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para> | |
215 | </listitem> | |
216 | </varlistentry> | |
217 | ||
218 | <varlistentry> | |
219 | <term><varname>fsck.mode=</varname></term> | |
220 | <term><varname>fsck.repair=</varname></term> | |
221 | ||
222 | <listitem> | |
223 | <para>Parameters understood by the file system checker | |
224 | services. For details, see | |
225 | <citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
226 | </listitem> | |
227 | </varlistentry> | |
228 | ||
229 | <varlistentry> | |
230 | <term><varname>quotacheck.mode=</varname></term> | |
231 | ||
232 | <listitem> | |
233 | <para>Parameter understood by the file quota checker | |
234 | service. For details, see | |
235 | <citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
236 | </listitem> | |
237 | </varlistentry> | |
238 | ||
239 | <varlistentry> | |
240 | <term><varname>systemd.journald.forward_to_syslog=</varname></term> | |
241 | <term><varname>systemd.journald.forward_to_kmsg=</varname></term> | |
242 | <term><varname>systemd.journald.forward_to_console=</varname></term> | |
243 | <term><varname>systemd.journald.forward_to_wall=</varname></term> | |
244 | ||
245 | <listitem> | |
246 | <para>Parameters understood by the journal service. For | |
247 | details, see | |
248 | <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
249 | </listitem> | |
250 | </varlistentry> | |
251 | ||
252 | <varlistentry> | |
253 | <term><varname>vconsole.keymap=</varname></term> | |
72ccee50 | 254 | <term><varname>vconsole.keymap_toggle=</varname></term> |
798d3a52 | 255 | <term><varname>vconsole.font=</varname></term> |
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256 | <term><varname>vconsole.font_map=</varname></term> |
257 | <term><varname>vconsole.font_unimap=</varname></term> | |
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258 | |
259 | <listitem> | |
72ccee50 ZJS |
260 | <para>Parameters understood by the virtual console setup logic. For details, see |
261 | <citerefentry><refentrytitle>vconsole.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
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262 | </listitem> |
263 | </varlistentry> | |
264 | ||
265 | <varlistentry> | |
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266 | <term><varname>udev.log_level=</varname></term> |
267 | <term><varname>rd.udev.log_level=</varname></term> | |
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268 | <term><varname>udev.children_max=</varname></term> |
269 | <term><varname>rd.udev.children_max=</varname></term> | |
270 | <term><varname>udev.exec_delay=</varname></term> | |
271 | <term><varname>rd.udev.exec_delay=</varname></term> | |
272 | <term><varname>udev.event_timeout=</varname></term> | |
273 | <term><varname>rd.udev.event_timeout=</varname></term> | |
e2099267 MS |
274 | <term><varname>udev.timeout_signal=</varname></term> |
275 | <term><varname>rd.udev.timeout_signal=</varname></term> | |
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276 | <term><varname>udev.blockdev_read_only</varname></term> |
277 | <term><varname>rd.udev.blockdev_read_only</varname></term> | |
798d3a52 | 278 | <term><varname>net.ifnames=</varname></term> |
f7e81fd9 | 279 | <term><varname>net.naming-scheme=</varname></term> |
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280 | |
281 | <listitem> | |
282 | <para>Parameters understood by the device event managing | |
283 | daemon. For details, see | |
284 | <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
285 | </listitem> | |
286 | </varlistentry> | |
287 | ||
288 | <varlistentry> | |
289 | <term><varname>plymouth.enable=</varname></term> | |
290 | ||
291 | <listitem> | |
292 | <para>May be used to disable the Plymouth boot splash. For | |
293 | details, see | |
294 | <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
295 | </listitem> | |
296 | </varlistentry> | |
297 | ||
298 | <varlistentry> | |
299 | <term><varname>luks=</varname></term> | |
300 | <term><varname>rd.luks=</varname></term> | |
301 | <term><varname>luks.crypttab=</varname></term> | |
302 | <term><varname>rd.luks.crypttab=</varname></term> | |
303 | <term><varname>luks.name=</varname></term> | |
304 | <term><varname>rd.luks.name=</varname></term> | |
305 | <term><varname>luks.uuid=</varname></term> | |
306 | <term><varname>rd.luks.uuid=</varname></term> | |
307 | <term><varname>luks.options=</varname></term> | |
308 | <term><varname>rd.luks.options=</varname></term> | |
309 | <term><varname>luks.key=</varname></term> | |
310 | <term><varname>rd.luks.key=</varname></term> | |
311 | ||
312 | <listitem> | |
313 | <para>Configures the LUKS full-disk encryption logic at | |
314 | boot. For details, see | |
315 | <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
316 | </listitem> | |
317 | </varlistentry> | |
318 | ||
319 | <varlistentry> | |
320 | <term><varname>fstab=</varname></term> | |
321 | <term><varname>rd.fstab=</varname></term> | |
322 | ||
323 | <listitem> | |
324 | <para>Configures the <filename>/etc/fstab</filename> logic | |
325 | at boot. For details, see | |
326 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
327 | </listitem> | |
328 | </varlistentry> | |
329 | ||
330 | <varlistentry> | |
331 | <term><varname>root=</varname></term> | |
332 | <term><varname>rootfstype=</varname></term> | |
d6a12e7c | 333 | <term><varname>rootflags=</varname></term> |
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334 | <term><varname>ro</varname></term> |
335 | <term><varname>rw</varname></term> | |
336 | ||
337 | <listitem> | |
338 | <para>Configures the root file system and its file system | |
339 | type and mount options, as well as whether it shall be | |
17ec531f | 340 | mounted read-only or read-write initially. For details, |
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341 | see |
342 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
343 | </listitem> | |
344 | </varlistentry> | |
345 | ||
6dfcea32 TH |
346 | <varlistentry> |
347 | <term><varname>mount.usr=</varname></term> | |
348 | <term><varname>mount.usrfstype=</varname></term> | |
349 | <term><varname>mount.usrflags=</varname></term> | |
350 | ||
351 | <listitem> | |
352 | <para>Configures the /usr file system (if required) and | |
353 | its file system type and mount options. For details, see | |
354 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
355 | </listitem> | |
356 | </varlistentry> | |
357 | ||
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358 | <varlistentry> |
359 | <term><varname>roothash=</varname></term> | |
360 | <term><varname>systemd.verity=</varname></term> | |
361 | <term><varname>rd.systemd.verity=</varname></term> | |
362 | <term><varname>systemd.verity_root_data=</varname></term> | |
363 | <term><varname>systemd.verity_root_hash=</varname></term> | |
364 | <listitem> | |
365 | <para>Configures the integrity protection root hash for the root file system, and other related | |
366 | parameters. For details, see | |
367 | <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
368 | </listitem> | |
369 | </varlistentry> | |
370 | ||
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371 | <varlistentry> |
372 | <term><varname>systemd.gpt_auto=</varname></term> | |
373 | <term><varname>rd.systemd.gpt_auto=</varname></term> | |
374 | ||
375 | <listitem> | |
376 | <para>Configures whether GPT based partition auto-discovery | |
377 | shall be attempted. For details, see | |
378 | <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
379 | </listitem> | |
380 | </varlistentry> | |
381 | ||
959718c6 TB |
382 | <varlistentry> |
383 | <term><varname>systemd.default_timeout_start_sec=</varname></term> | |
384 | ||
385 | <listitem> | |
386 | <para>Overwrites the default start job timeout <varname>DefaultTimeoutStartSec=</varname> at boot. For details, | |
387 | see <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
c75396c3 EJ |
388 | </listitem> |
389 | </varlistentry> | |
390 | ||
391 | <varlistentry> | |
392 | <term><varname>systemd.watchdog_device=</varname></term> | |
393 | ||
394 | <listitem> | |
395 | <para>Overwrites the watchdog device path <varname>WatchdogDevice=</varname>. For details, see | |
396 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
959718c6 TB |
397 | </listitem> |
398 | </varlistentry> | |
399 | ||
68d58f38 LP |
400 | <varlistentry> |
401 | <term><varname>systemd.cpu_affinity=</varname></term> | |
402 | ||
403 | <listitem> | |
404 | <para>Overrides the CPU affinity mask for the service manager and the default for all child | |
405 | processes it forks. This takes precedence over <varname>CPUAffinity=</varname>, see | |
406 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
407 | for details.</para> | |
408 | </listitem> | |
409 | </varlistentry> | |
410 | ||
798d3a52 | 411 | <varlistentry> |
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412 | <term><varname>modules_load=</varname></term> |
413 | <term><varname>rd.modules_load=</varname></term> | |
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414 | |
415 | <listitem> | |
416 | <para>Load a specific kernel module early at boot. For | |
417 | details, see | |
418 | <citerefentry><refentrytitle>systemd-modules-load.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
419 | </listitem> | |
420 | </varlistentry> | |
421 | ||
422 | <varlistentry> | |
423 | <term><varname>resume=</varname></term> | |
8b6805a2 | 424 | <term><varname>resumeflags=</varname></term> |
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425 | |
426 | <listitem> | |
427 | <para>Enables resume from hibernation using the specified | |
8b6805a2 | 428 | device and mount options. All |
3ba3a79d | 429 | <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>-like |
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430 | paths are supported. For details, see |
431 | <citerefentry><refentrytitle>systemd-hibernate-resume-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para> | |
432 | </listitem> | |
433 | </varlistentry> | |
f582cbca LP |
434 | |
435 | <varlistentry> | |
436 | <term><varname>systemd.firstboot=</varname></term> | |
437 | ||
438 | <listitem><para>Takes a boolean argument, defaults to on. If off, | |
439 | <citerefentry><refentrytitle>systemd-firstboot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
814872e9 LP |
440 | will not query the user for basic system settings, even if the system boots up for the first time and |
441 | the relevant settings are not initialized yet. Not to be confused with | |
442 | <varname>systemd.condition-first-boot=</varname> (see below), which overrides the result of the | |
443 | <varname>ConditionFirstBoot=</varname> unit file condition, and thus controls more than just | |
444 | <filename>systemd-firstboot.service</filename> behaviour.</para></listitem> | |
f582cbca | 445 | </varlistentry> |
f8b4ae29 LP |
446 | |
447 | <varlistentry> | |
448 | <term><varname>systemd.condition-needs-update=</varname></term> | |
449 | ||
450 | <listitem><para>Takes a boolean argument. If specified, overrides the result of | |
451 | <varname>ConditionNeedsUpdate=</varname> unit condition checks. See | |
452 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
453 | details.</para></listitem> | |
454 | </varlistentry> | |
814872e9 LP |
455 | |
456 | <varlistentry> | |
457 | <term><varname>systemd.condition-first-boot=</varname></term> | |
458 | ||
459 | <listitem><para>Takes a boolean argument. If specified, overrides the result of | |
460 | <varname>ConditionFirstBoot=</varname> unit condition checks. See | |
461 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for | |
462 | details. Not to be confused with <varname>systemd.firstboot=</varname> which only controls behaviour | |
463 | of the <filename>systemd-firstboot.service</filename> system service but has no effect on the | |
464 | condition check (see above).</para></listitem> | |
465 | </varlistentry> | |
3753325b LP |
466 | |
467 | <varlistentry> | |
468 | <term><varname>systemd.clock-usec=</varname></term> | |
469 | ||
470 | <listitem><para>Takes a decimal, numeric timestamp in µs since January 1st 1970, 00:00am, to set the | |
18d9cee0 LP |
471 | system clock to. The system time is set to the specified timestamp early during boot. It is not |
472 | propagated to the hardware clock (RTC).</para></listitem> | |
473 | </varlistentry> | |
474 | ||
475 | <varlistentry> | |
476 | <term><varname>systemd.random-seed=</varname></term> | |
477 | ||
478 | <listitem><para>Takes a base64 encoded random seed value to credit with full entropy to the kernel's | |
479 | random pool during early service manager initialization. This option is useful in testing | |
480 | environments where delays due to random pool initialization in entropy starved virtual machines shall | |
481 | be avoided.</para> | |
482 | ||
483 | <para>Note that if this option is used the seed is accessible to unprivileged programs from | |
484 | <filename>/proc/cmdline</filename>. This option is hence a security risk when used outside of test | |
485 | systems, since the (possibly) only seed used for initialization of the kernel's entropy pool might be | |
486 | easily acquired by unprivileged programs.</para> | |
487 | ||
488 | <para>It is recommended to pass 512 bytes of randomized data (as that matches the Linux kernel pool | |
489 | size), which may be generated with a command like the following:</para> | |
490 | ||
491 | <programlisting>dd if=/dev/urandom bs=512 count=1 status=none | base64 -w 0</programlisting> | |
492 | ||
493 | <para>Again: do not use this option outside of testing environments, it's a security risk elsewhere, | |
494 | as secret key material derived from the entropy pool can possibly be reconstructed by unprivileged | |
495 | programs.</para> | |
496 | </listitem> | |
3753325b | 497 | </varlistentry> |
34293dfa LP |
498 | |
499 | <varlistentry> | |
500 | <term><varname>systemd.hostname=</varname></term> | |
501 | ||
502 | <listitem><para>Accepts a hostname to set during early boot. If specified takes precedence over what | |
503 | is set in <filename>/etc/hostname</filename>. Note that this does not bar later runtime changes to | |
504 | the hostname, it simply controls the initial hostname set during early boot.</para></listitem> | |
505 | </varlistentry> | |
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506 | </variablelist> |
507 | ||
508 | </refsect1> | |
509 | ||
510 | <refsect1> | |
511 | <title>See Also</title> | |
512 | <para> | |
513 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
d1698b82 | 514 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
798d3a52 | 515 | <citerefentry project='man-pages'><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
af105d03 | 516 | <citerefentry project='man-pages'><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
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517 | <citerefentry><refentrytitle>systemd-debug-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
518 | <citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
519 | <citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
520 | <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
521 | <citerefentry><refentrytitle>systemd-vconsole-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
522 | <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
523 | <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
524 | <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
2f3dfc6f | 525 | <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
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526 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
527 | <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
91214a37 | 528 | <citerefentry><refentrytitle>systemd-volatile-root.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
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529 | <citerefentry><refentrytitle>systemd-modules-load.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
530 | <citerefentry><refentrytitle>systemd-backlight@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
af105d03 | 531 | <citerefentry><refentrytitle>systemd-rfkill.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
f582cbca | 532 | <citerefentry><refentrytitle>systemd-hibernate-resume-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
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533 | <citerefentry><refentrytitle>systemd-firstboot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
534 | <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
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535 | </para> |
536 | </refsect1> | |
c66e7bc7 LP |
537 | |
538 | </refentry> |