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f37d3835 | 1 | <?xml version='1.0'?> <!--*-nxml-*--> |
3a54a157 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
f37d3835 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
db9ecf05 | 4 | <!-- SPDX-License-Identifier: LGPL-2.1-or-later --> |
f37d3835 | 5 | |
dfca5587 | 6 | <refentry id="systemd-boot" conditional='ENABLE_BOOTLOADER' |
f37d3835 ZJS |
7 | xmlns:xi="http://www.w3.org/2001/XInclude"> |
8 | <refentryinfo> | |
70c8db75 | 9 | <title>systemd-boot</title> |
f37d3835 | 10 | <productname>systemd</productname> |
f37d3835 ZJS |
11 | </refentryinfo> |
12 | ||
13 | <refmeta> | |
70c8db75 | 14 | <refentrytitle>systemd-boot</refentrytitle> |
f37d3835 ZJS |
15 | <manvolnum>7</manvolnum> |
16 | </refmeta> | |
17 | ||
18 | <refnamediv> | |
70c8db75 | 19 | <refname>systemd-boot</refname> |
f37d3835 ZJS |
20 | <refname>sd-boot</refname> |
21 | <refpurpose>A simple UEFI boot manager</refpurpose> | |
22 | </refnamediv> | |
23 | ||
24 | <refsect1> | |
25 | <title>Description</title> | |
26 | ||
c5fcaed8 | 27 | <para><command>systemd-boot</command> (short: <command>sd-boot</command>) is a simple UEFI boot |
b8cdb662 | 28 | manager. It provides a textual menu to select the entry to boot and an editor for the kernel command |
c5fcaed8 | 29 | line. <command>systemd-boot</command> supports systems with UEFI firmware only.</para> |
53ddb667 | 30 | |
39867bb9 LP |
31 | <para><command>systemd-boot</command> loads boot entry information from the EFI system partition (ESP), |
32 | usually mounted at <filename>/efi/</filename>, <filename>/boot/</filename>, or | |
cafa9d87 LP |
33 | <filename>/boot/efi/</filename> during OS runtime, as well as from the Extended Boot Loader partition |
34 | (XBOOTLDR) if it exists (usually mounted to <filename>/boot/</filename>). Configuration file fragments, | |
35 | kernels, initrds and other EFI images to boot generally need to reside on the ESP or the Extended Boot | |
36 | Loader partition. Linux kernels must be built with <option>CONFIG_EFI_STUB</option> to be able to be | |
37 | directly executed as an EFI image. During boot <command>systemd-boot</command> automatically assembles a | |
38 | list of boot entries from the following sources:</para> | |
53ddb667 LP |
39 | |
40 | <itemizedlist> | |
41 | <listitem><para>Boot entries defined with <ulink | |
db811444 | 42 | url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink> Type #1 |
a0aa3838 ZJS |
43 | description files located in <filename>/loader/entries/</filename> on the ESP and the Extended Boot |
44 | Loader Partition. These usually describe Linux kernel images with associated initrd images, but | |
45 | alternatively may also describe other arbitrary EFI executables.</para></listitem> | |
53ddb667 | 46 | |
db811444 | 47 | <listitem><para>Unified kernel images, <ulink url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot |
a0aa3838 ZJS |
48 | Loader Specification</ulink> Type #2, which are executable EFI binaries in |
49 | <filename>/EFI/Linux/</filename> on the ESP and the Extended Boot Loader Partition.</para></listitem> | |
53ddb667 | 50 | |
a0aa3838 | 51 | <listitem><para>The Microsoft Windows EFI boot manager, if installed.</para></listitem> |
53ddb667 | 52 | |
a0aa3838 | 53 | <listitem><para>The Apple macOS boot manager, if installed.</para></listitem> |
53ddb667 | 54 | |
a0aa3838 | 55 | <listitem><para>The EFI Shell binary, if installed.</para></listitem> |
53ddb667 | 56 | |
a0aa3838 | 57 | <listitem><para>A reboot into the UEFI firmware setup option, if supported by the firmware.</para></listitem> |
e6b0cfad | 58 | |
8b9f0921 | 59 | <listitem><para>Secure Boot variables enrollment if the UEFI firmware is in setup-mode and files are provided |
e6b0cfad | 60 | on the ESP.</para></listitem> |
53ddb667 LP |
61 | </itemizedlist> |
62 | ||
39867bb9 LP |
63 | <para><command>systemd-boot</command> supports the following features:</para> |
64 | ||
65 | <itemizedlist> | |
66 | <listitem><para>Basic boot manager configuration changes (such as timeout | |
67 | configuration, default boot entry selection, …) may be made directly from the boot loader UI at | |
68 | boot-time, as well as during system runtime with EFI variables.</para></listitem> | |
69 | ||
70 | <listitem><para>The boot manager integrates with the <command>systemctl</command> command to implement | |
71 | features such as <command>systemctl reboot --boot-loader-entry=…</command> (for rebooting into a | |
72 | specific boot menu entry, i.e. "reboot into Windows") and <command>systemctl reboot | |
73 | --boot-loader-menu=…</command> (for rebooting into the boot loader menu), by implementing the <ulink | |
74 | url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>. See | |
75 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for | |
76 | details.</para></listitem> | |
77 | ||
250db1bf | 78 | <listitem><para>An EFI variable set by the boot loader informs the OS about the EFI System Partition used |
79 | during boot. This is then used to automatically mount the correct EFI System Partition to | |
39867bb9 LP |
80 | <filename>/efi/</filename> or <filename>/boot/</filename> during OS runtime. See |
81 | <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
82 | for details.</para></listitem> | |
83 | ||
84 | <listitem><para>The boot manager provides information about the boot time spent in UEFI firmware using | |
85 | the <ulink url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>. This | |
86 | information can be displayed using | |
87 | <citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry>. | |
88 | </para></listitem> | |
89 | ||
90 | <listitem><para>The boot manager implements boot counting and automatic fallback to older, working boot | |
91 | entries on failure. See <ulink url="https://systemd.io/AUTOMATIC_BOOT_ASSESSMENT">Automatic Boot | |
92 | Assessment</ulink>.</para></listitem> | |
93 | ||
94 | <listitem><para>The boot manager optionally reads a random seed from the ESP partition, combines it | |
11fcfc53 | 95 | with a 'system token' stored in a persistent EFI variable and derives a random seed to use by the OS as |
e9dd6984 | 96 | entropy pool initialization, providing a full entropy pool during early boot.</para></listitem> |
e6b0cfad | 97 | |
8b9f0921 | 98 | <listitem><para>The boot manager allows for Secure Boot variables to be enrolled if the UEFI firmware is |
e6b0cfad | 99 | in setup-mode. Additionally, variables can be automatically enrolled if configured.</para></listitem> |
39867bb9 LP |
100 | </itemizedlist> |
101 | ||
102 | <para><citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
c5fcaed8 LP |
103 | may be used from a running system to locate the ESP and the Extended Boot Loader Partition, list |
104 | available entries, and install <command>systemd-boot</command> itself.</para> | |
53ddb667 | 105 | |
39867bb9 LP |
106 | <para><citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
107 | may be used to copy kernel images onto the ESP or the Extended Boot Loader Partition and to generate | |
108 | description files compliant with the Boot Loader | |
109 | Specification.</para> | |
3f9a615d LP |
110 | |
111 | <para><citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
112 | may be used as UEFI boot stub for executed kernels, which is useful to show graphical boot splashes | |
113 | before transitioning into the Linux world. It is also capable of automatically picking up auxiliary | |
114 | credential files (for boot parameterization) and system extension images, as companion files to the | |
115 | booted kernel images.</para> | |
f37d3835 ZJS |
116 | </refsect1> |
117 | ||
f37d3835 ZJS |
118 | <refsect1> |
119 | <title>Key bindings</title> | |
120 | <para>The following keys may be used in the boot menu:</para> | |
121 | ||
8a8e5666 JJ |
122 | <!-- Developer commands Q/v/Ctrl+l deliberately not advertised. --> |
123 | ||
f37d3835 ZJS |
124 | <variablelist> |
125 | <varlistentry> | |
8c073dde LP |
126 | <term><keycap>↑</keycap> (Up)</term> |
127 | <term><keycap>↓</keycap> (Down)</term> | |
128 | <term><keycap>j</keycap></term> | |
129 | <term><keycap>k</keycap></term> | |
130 | <term><keycap>PageUp</keycap></term> | |
131 | <term><keycap>PageDown</keycap></term> | |
132 | <term><keycap>Home</keycap></term> | |
133 | <term><keycap>End</keycap></term> | |
ec07c3c8 AK |
134 | <listitem><para>Navigate up/down in the entry list</para> |
135 | ||
136 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
137 | </varlistentry> |
138 | ||
139 | <varlistentry> | |
8c073dde | 140 | <term><keycap>↵</keycap> (Enter)</term> |
904ebcb2 | 141 | <term><keycap>→</keycap> (Right)</term> |
ec07c3c8 AK |
142 | <listitem><para>Boot selected entry</para> |
143 | ||
144 | <xi:include href="version-info.xml" xpointer="v246"/></listitem> | |
f37d3835 ZJS |
145 | </varlistentry> |
146 | ||
147 | <varlistentry> | |
8c073dde | 148 | <term><keycap>d</keycap></term> |
ec07c3c8 AK |
149 | <listitem><para>Make selected entry the default</para> |
150 | ||
151 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
152 | </varlistentry> |
153 | ||
154 | <varlistentry> | |
8c073dde | 155 | <term><keycap>e</keycap></term> |
ec07c3c8 AK |
156 | <listitem><para>Edit the kernel command line for selected entry</para> |
157 | ||
158 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
159 | </varlistentry> |
160 | ||
161 | <varlistentry> | |
8c073dde LP |
162 | <term><keycap>+</keycap></term> |
163 | <term><keycap>t</keycap></term> | |
ec07c3c8 AK |
164 | <listitem><para>Increase the timeout before default entry is booted</para> |
165 | ||
166 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
167 | </varlistentry> |
168 | ||
169 | <varlistentry> | |
8c073dde LP |
170 | <term><keycap>-</keycap></term> |
171 | <term><keycap>T</keycap></term> | |
ec07c3c8 AK |
172 | <listitem><para>Decrease the timeout</para> |
173 | ||
174 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
175 | </varlistentry> |
176 | ||
1b965abc JJ |
177 | <varlistentry> |
178 | <term><keycap>r</keycap></term> | |
ec07c3c8 AK |
179 | <listitem><para>Change screen resolution, skipping any unsupported modes.</para> |
180 | ||
181 | <xi:include href="version-info.xml" xpointer="v250"/></listitem> | |
1b965abc JJ |
182 | </varlistentry> |
183 | ||
184 | <varlistentry> | |
185 | <term><keycap>R</keycap></term> | |
ec07c3c8 AK |
186 | <listitem><para>Reset screen resolution to firmware or configuration file default.</para> |
187 | ||
188 | <xi:include href="version-info.xml" xpointer="v250"/></listitem> | |
1b965abc JJ |
189 | </varlistentry> |
190 | ||
f37d3835 | 191 | <varlistentry> |
8a8e5666 | 192 | <term><keycap>p</keycap></term> |
ec07c3c8 AK |
193 | <listitem><para>Print status</para> |
194 | ||
195 | <xi:include href="version-info.xml" xpointer="v250"/></listitem> | |
f37d3835 ZJS |
196 | </varlistentry> |
197 | ||
f37d3835 | 198 | <varlistentry> |
8c073dde LP |
199 | <term><keycap>h</keycap></term> |
200 | <term><keycap>?</keycap></term> | |
a318a565 | 201 | <term><keycap>F1</keycap></term> |
f37d3835 ZJS |
202 | <listitem><para>Show a help screen</para></listitem> |
203 | </varlistentry> | |
e6cab77e JJ |
204 | |
205 | <varlistentry> | |
206 | <term><keycap>f</keycap></term> | |
207 | <listitem><para>Reboot into firmware interface.</para> | |
208 | ||
209 | <para>For compatibility with the keybindings of several firmware implementations this operation | |
210 | may also be reached with <keycap>F2</keycap>, <keycap>F10</keycap>, <keycap>Del</keycap> and | |
ec07c3c8 AK |
211 | <keycap>Esc</keycap>.</para> |
212 | ||
213 | <xi:include href="version-info.xml" xpointer="v250"/></listitem> | |
e6cab77e | 214 | </varlistentry> |
f6531b11 LP |
215 | |
216 | <varlistentry> | |
217 | <term><keycombo><keycap>Shift</keycap><keycap>o</keycap></keycombo></term> | |
ec07c3c8 AK |
218 | <listitem><para>Power off the system.</para> |
219 | ||
220 | <xi:include href="version-info.xml" xpointer="v255"/></listitem> | |
f6531b11 LP |
221 | </varlistentry> |
222 | ||
223 | <varlistentry> | |
224 | <term><keycombo><keycap>Shift</keycap><keycap>b</keycap></keycombo></term> | |
ec07c3c8 AK |
225 | <listitem><para>Reboot the system.</para> |
226 | ||
227 | <xi:include href="version-info.xml" xpointer="v255"/></listitem> | |
f6531b11 | 228 | </varlistentry> |
f37d3835 ZJS |
229 | </variablelist> |
230 | ||
e14a0c21 LP |
231 | <para>The following keys may be pressed during bootup or in the boot menu to directly boot a specific |
232 | entry:</para> | |
f37d3835 ZJS |
233 | |
234 | <variablelist> | |
235 | <varlistentry> | |
8c073dde | 236 | <term><keycap>l</keycap></term> |
ec07c3c8 AK |
237 | <listitem><para>Linux</para> |
238 | ||
239 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
240 | </varlistentry> |
241 | ||
242 | <varlistentry> | |
8c073dde | 243 | <term><keycap>w</keycap></term> |
ec07c3c8 AK |
244 | <listitem><para>Windows</para> |
245 | ||
246 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
247 | </varlistentry> |
248 | ||
249 | <varlistentry> | |
8c073dde | 250 | <term><keycap>a</keycap></term> |
ec07c3c8 AK |
251 | <listitem><para>macOS</para> |
252 | ||
253 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
254 | </varlistentry> |
255 | ||
256 | <varlistentry> | |
8c073dde | 257 | <term><keycap>s</keycap></term> |
ec07c3c8 AK |
258 | <listitem><para>EFI shell</para> |
259 | ||
260 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
261 | </varlistentry> |
262 | ||
263 | <varlistentry> | |
8c073dde LP |
264 | <term><keycap>1</keycap></term> |
265 | <term><keycap>2</keycap></term> | |
266 | <term><keycap>3</keycap></term> | |
267 | <term><keycap>4</keycap></term> | |
268 | <term><keycap>5</keycap></term> | |
269 | <term><keycap>6</keycap></term> | |
270 | <term><keycap>7</keycap></term> | |
271 | <term><keycap>8</keycap></term> | |
272 | <term><keycap>9</keycap></term> | |
ec07c3c8 AK |
273 | <listitem><para>Boot entry number 1 … 9</para> |
274 | ||
275 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
276 | </varlistentry> |
277 | </variablelist> | |
278 | ||
e14a0c21 LP |
279 | <para>The boot menu is shown when a non-zero menu timeout has been configured. If the menu timeout has |
280 | been set to zero, it is sufficient to press any key — before the boot loader initializes — to bring up | |
281 | the boot menu, except for the keys listed immediately above as they directly boot into the selected boot | |
282 | menu item. Note that depending on the firmware implementation the time window where key presses are | |
283 | accepted before the boot loader initializes might be short. If the window is missed, reboot and try | |
284 | again, possibly pressing a suitable key (e.g. the space bar) continuously; on most systems it should be | |
285 | possible to hit the time window after a few attempts. To avoid this problem, consider setting a non-zero | |
286 | timeout, thus showing the boot menu unconditionally. Some desktop environments might offer an option to | |
287 | directly boot into the boot menu, to avoid the problem altogether. Alternatively, use the command line | |
288 | <command>systemctl reboot --boot-loader-menu=0</command> from the shell.</para> | |
289 | ||
f37d3835 ZJS |
290 | <para>In the editor, most keys simply insert themselves, but the following keys |
291 | may be used to perform additional actions:</para> | |
292 | ||
293 | <variablelist> | |
294 | <varlistentry> | |
8c073dde LP |
295 | <term><keycap>←</keycap> (Left)</term> |
296 | <term><keycap>→</keycap> (Right)</term> | |
297 | <term><keycap>Home</keycap></term> | |
298 | <term><keycap>End</keycap></term> | |
ec07c3c8 AK |
299 | <listitem><para>Navigate left/right</para> |
300 | ||
301 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
302 | </varlistentry> |
303 | ||
304 | <varlistentry> | |
8c073dde | 305 | <term><keycap>Esc</keycap></term> |
230f7820 | 306 | <term><keycombo><keycap>Ctrl</keycap><keycap>c</keycap></keycombo></term> |
f37d3835 ZJS |
307 | <listitem><para>Abort the edit and quit the editor</para></listitem> |
308 | </varlistentry> | |
309 | ||
310 | <varlistentry> | |
8c073dde | 311 | <term><keycombo><keycap>Ctrl</keycap><keycap>k</keycap></keycombo></term> |
ec07c3c8 AK |
312 | <listitem><para>Clear the command line forwards</para> |
313 | ||
314 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
f37d3835 ZJS |
315 | </varlistentry> |
316 | ||
317 | <varlistentry> | |
8c073dde LP |
318 | <term><keycombo><keycap>Ctrl</keycap><keycap>w</keycap></keycombo></term> |
319 | <term><keycombo><keycap>Alt</keycap><keycap>Backspace</keycap></keycombo></term> | |
ec07c3c8 AK |
320 | <listitem><para>Delete word backwards</para> |
321 | ||
322 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
f37d3835 ZJS |
323 | </varlistentry> |
324 | ||
325 | <varlistentry> | |
230f7820 | 326 | <term><keycombo><keycap>Ctrl</keycap><keycap>Del</keycap></keycombo></term> |
8c073dde | 327 | <term><keycombo><keycap>Alt</keycap><keycap>d</keycap></keycombo></term> |
f37d3835 ZJS |
328 | <listitem><para>Delete word forwards</para></listitem> |
329 | </varlistentry> | |
330 | ||
331 | <varlistentry> | |
8c073dde | 332 | <term><keycap>↵</keycap> (Enter)</term> |
ec07c3c8 AK |
333 | <listitem><para>Boot entry with the edited command line</para> |
334 | ||
335 | <xi:include href="version-info.xml" xpointer="v239"/></listitem> | |
f37d3835 ZJS |
336 | </varlistentry> |
337 | </variablelist> | |
338 | ||
70c8db75 | 339 | <para>Note that unless configured otherwise in the UEFI firmware, systemd-boot will |
f37d3835 ZJS |
340 | use the US keyboard layout, so key labels might not match for keys like +/-. |
341 | </para> | |
342 | </refsect1> | |
343 | ||
53ddb667 LP |
344 | <refsect1> |
345 | <title>Files</title> | |
346 | ||
c5fcaed8 LP |
347 | <para>The files <command>systemd-boot</command> processes generally reside on the UEFI ESP which is |
348 | usually mounted to <filename>/efi/</filename>, <filename>/boot/</filename> or | |
349 | <filename>/boot/efi/</filename> during OS runtime. It also processes files on the Extended Boot Loader | |
350 | partition which is typically mounted to <filename>/boot/</filename>, if it | |
99d51ed9 LP |
351 | exists.</para> |
352 | ||
353 | <para><command>systemd-boot</command> reads runtime configuration such as the boot timeout and default | |
c5fcaed8 LP |
354 | entry from <filename>/loader/loader.conf</filename> on the ESP (in combination with data read from EFI |
355 | variables). See | |
99d51ed9 LP |
356 | <citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> |
357 | ||
358 | <para>Boot entry description files following the <ulink | |
db811444 | 359 | url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink> are read from |
99d51ed9 LP |
360 | <filename>/loader/entries/</filename> on the ESP and the Extended Boot Loader partition.</para> |
361 | ||
362 | <para>Unified kernel boot entries following the <ulink | |
db811444 | 363 | url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink> are read from |
99d51ed9 LP |
364 | <filename>/EFI/Linux/</filename> on the ESP and the Extended Boot Loader partition.</para> |
365 | ||
366 | <para>Optionally, a random seed for early boot entropy pool provisioning is stored in | |
367 | <filename>/loader/random-seed</filename> in the ESP.</para> | |
368 | ||
369 | <para>During initialization, <command>sd-boot</command> automatically loads all driver files placed in | |
370 | the <filename>/EFI/systemd/drivers/</filename> directory of the ESP. The files placed there must have an | |
371 | extension of the EFI architecture ID followed by <filename>.efi</filename> (e.g. for x86-64 this means a | |
372 | suffix of <filename>x64.efi</filename>). This may be used to automatically load file system drivers and | |
373 | similar, to extend the native firmware support.</para> | |
e6b0cfad VD |
374 | |
375 | <para>Enrollment of Secure Boot variables can be performed manually or automatically if files are available | |
8d41101a | 376 | under <filename>/loader/keys/<replaceable>NAME</replaceable>/{db,KEK,PK}.auth</filename>, <replaceable>NAME</replaceable> |
e6b0cfad VD |
377 | being the display name for the set of variables in the menu. If one of the sets is named <filename>auto</filename> |
378 | then it might be enrolled automatically depending on whether <literal>secure-boot-enroll</literal> is set | |
379 | to force or not.</para> | |
53ddb667 LP |
380 | </refsect1> |
381 | ||
8eebff9e LP |
382 | <refsect1> |
383 | <title>EFI Variables</title> | |
384 | ||
b8cdb662 LP |
385 | <para>The following EFI variables are defined, set and read by <command>systemd-boot</command>, under the |
386 | vendor UUID <literal>4a67b082-0a4c-41cf-b6c7-440b29bb8c4f</literal>, for communication between the boot | |
387 | loader and the OS:</para> | |
8eebff9e | 388 | |
bc61c2b1 | 389 | <variablelist class='efi-variables'> |
8eebff9e LP |
390 | <varlistentry> |
391 | <term><varname>LoaderBootCountPath</varname></term> | |
392 | <listitem><para>If boot counting is enabled, contains the path to the file in whose name the boot counters are | |
393 | encoded. Set by the boot | |
394 | loader. <citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
395 | uses this information to mark a boot as successful as determined by the successful activation of the | |
ec07c3c8 AK |
396 | <filename>boot-complete.target</filename> target unit.</para> |
397 | ||
398 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
399 | </varlistentry> |
400 | ||
401 | <varlistentry> | |
402 | <term><varname>LoaderConfigTimeout</varname></term> | |
fe2579dd | 403 | <term><varname>LoaderConfigTimeoutOneShot</varname></term> |
3f9a0a52 | 404 | <listitem><para>The menu timeout in seconds. Read by the boot loader. <varname>LoaderConfigTimeout</varname> |
fe2579dd LP |
405 | is maintained persistently, while <varname>LoaderConfigTimeoutOneShot</varname> is a one-time override which is |
406 | read once (in which case it takes precedence over <varname>LoaderConfigTimeout</varname>) and then | |
407 | removed. <varname>LoaderConfigTimeout</varname> may be manipulated with the | |
ec07c3c8 AK |
408 | <keycap>t</keycap>/<keycap>T</keycap> keys, see above.</para> |
409 | ||
410 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
411 | </varlistentry> |
412 | ||
413 | <varlistentry> | |
414 | <term><varname>LoaderDevicePartUUID</varname></term> | |
415 | ||
416 | <listitem><para>Contains the partition UUID of the EFI System Partition the boot loader was run from. Set by | |
417 | the boot | |
418 | loader. <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
419 | uses this information to automatically find the disk booted from, in order to discover various other partitions | |
ec07c3c8 AK |
420 | on the same disk automatically.</para> |
421 | ||
422 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
423 | </varlistentry> |
424 | ||
425 | <varlistentry> | |
426 | <term><varname>LoaderEntries</varname></term> | |
427 | ||
428 | <listitem><para>A list of the identifiers of all discovered boot loader entries. Set by the boot | |
ec07c3c8 AK |
429 | loader.</para> |
430 | ||
431 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
432 | </varlistentry> |
433 | ||
434 | <varlistentry> | |
435 | <term><varname>LoaderEntryDefault</varname></term> | |
436 | <term><varname>LoaderEntryOneShot</varname></term> | |
437 | ||
438 | <listitem><para>The identifier of the default boot loader entry. Set primarily by the OS and read by the boot | |
439 | loader. <varname>LoaderEntryOneShot</varname> sets the default entry for the next boot only, while | |
440 | <varname>LoaderEntryDefault</varname> sets it persistently for all future | |
441 | boots. <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s | |
442 | <option>set-default</option> and <option>set-oneshot</option> commands make use of these variables. The boot | |
443 | loader modifies <varname>LoaderEntryDefault</varname> on request, when the <keycap>d</keycap> key is used, see | |
ec07c3c8 AK |
444 | above.</para> |
445 | ||
446 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
447 | </varlistentry> |
448 | ||
449 | <varlistentry> | |
450 | <term><varname>LoaderEntrySelected</varname></term> | |
451 | ||
452 | <listitem><para>The identifier of the boot loader entry currently being booted. Set by the boot | |
ec07c3c8 AK |
453 | loader.</para> |
454 | ||
455 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
456 | </varlistentry> |
457 | ||
5dd5f7cf LP |
458 | <varlistentry> |
459 | <term><varname>LoaderFeatures</varname></term> | |
460 | ||
461 | <listitem><para>A set of flags indicating the features the boot loader supports. Set by the boot loader. Use | |
462 | <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this | |
ec07c3c8 AK |
463 | data.</para> |
464 | ||
465 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
5dd5f7cf LP |
466 | </varlistentry> |
467 | ||
8eebff9e LP |
468 | <varlistentry> |
469 | <term><varname>LoaderFirmwareInfo</varname></term> | |
470 | <term><varname>LoaderFirmwareType</varname></term> | |
471 | ||
472 | <listitem><para>Brief firmware information. Set by the boot loader. Use | |
473 | <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this | |
ec07c3c8 AK |
474 | data.</para> |
475 | ||
476 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
477 | </varlistentry> |
478 | ||
479 | <varlistentry> | |
480 | <term><varname>LoaderImageIdentifier</varname></term> | |
481 | ||
482 | <listitem><para>The path of executable of the boot loader used for the current boot, relative to the EFI System | |
483 | Partition's root directory. Set by the boot loader. Use | |
484 | <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this | |
ec07c3c8 AK |
485 | data.</para> |
486 | ||
487 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
488 | </varlistentry> |
489 | ||
490 | <varlistentry> | |
491 | <term><varname>LoaderInfo</varname></term> | |
492 | ||
493 | <listitem><para>Brief information about the boot loader. Set by the boot loader. Use | |
494 | <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this | |
ec07c3c8 AK |
495 | data.</para> |
496 | ||
497 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
8eebff9e LP |
498 | </varlistentry> |
499 | ||
500 | <varlistentry> | |
501 | <term><varname>LoaderTimeExecUSec</varname></term> | |
502 | <term><varname>LoaderTimeInitUSec</varname></term> | |
503 | <term><varname>LoaderTimeMenuUsec</varname></term> | |
504 | ||
505 | <listitem><para>Information about the time spent in various parts of the boot loader. Set by the boot | |
506 | loader. Use <citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
ec07c3c8 AK |
507 | to view this data. </para> |
508 | ||
509 | <xi:include href="version-info.xml" xpointer="v240"/></listitem> | |
39867bb9 LP |
510 | </varlistentry> |
511 | ||
39867bb9 LP |
512 | <varlistentry> |
513 | <term><varname>LoaderSystemToken</varname></term> | |
514 | ||
e9dd6984 ZJS |
515 | <listitem><para>A binary random data field, that is used for generating the random seed to pass to |
516 | the OS (see above). Note that this random data is generally only generated once, during OS | |
ec07c3c8 AK |
517 | installation, and is then never updated again.</para> |
518 | ||
519 | <xi:include href="version-info.xml" xpointer="v243"/></listitem> | |
8eebff9e LP |
520 | </varlistentry> |
521 | </variablelist> | |
39867bb9 LP |
522 | |
523 | <para>Many of these variables are defined by the <ulink | |
524 | url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>.</para> | |
8eebff9e LP |
525 | </refsect1> |
526 | ||
2b6cc3ca LP |
527 | <refsect1> |
528 | <title>Boot Counting</title> | |
529 | ||
530 | <para><command>systemd-boot</command> implements a simple boot counting mechanism on top of the <ulink | |
db811444 | 531 | url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink>, for automatic and unattended |
5238e957 | 532 | fallback to older kernel versions/boot loader entries when a specific entry continuously fails. Any boot loader |
2b6cc3ca LP |
533 | entry file and unified kernel image file that contains a <literal>+</literal> followed by one or two numbers (if |
534 | two they need to be separated by a <literal>-</literal>), before the <filename>.conf</filename> or | |
535 | <filename>.efi</filename> suffix is subject to boot counting: the first of the two numbers ('tries left') is | |
536 | decreased by one on every boot attempt, the second of the two numbers ('tries done') is increased by one (if 'tries | |
537 | done' is absent it is considered equivalent to 0). Depending on the current value of these two counters the boot | |
538 | entry is considered to be in one of three states:</para> | |
539 | ||
540 | <orderedlist> | |
541 | <listitem><para>If the 'tries left' counter of an entry is greater than zero the entry is considered to be in | |
542 | 'indeterminate' state. This means the entry has not completed booting successfully yet, but also hasn't been | |
543 | determined not to work.</para></listitem> | |
544 | ||
545 | <listitem><para>If the 'tries left' counter of an entry is zero it is considered to be in 'bad' state. This means | |
546 | no further attempts to boot this item will be made (that is, unless all other boot entries are also in 'bad' | |
547 | state), as all attempts to boot this entry have not completed successfully.</para></listitem> | |
548 | ||
549 | <listitem><para>If the 'tries left' and 'tries done' counters of an entry are absent it is considered to be in | |
550 | 'good' state. This means further boot counting for the entry is turned off, as it successfully booted at least | |
551 | once. The | |
552 | <citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
553 | service moves the currently booted entry from 'indeterminate' into 'good' state when a boot attempt completed | |
554 | successfully.</para></listitem> | |
555 | </orderedlist> | |
556 | ||
557 | <para>Generally, when new entries are added to the boot loader, they first start out in 'indeterminate' state, | |
558 | i.e. with a 'tries left' counter greater than zero. The boot entry remains in this state until either it managed to | |
559 | complete a full boot successfully at least once (in which case it will be in 'good' state) — or the 'tries left' | |
560 | counter reaches zero (in which case it will be in 'bad' state).</para> | |
561 | ||
562 | <para>Example: let's say a boot loader entry file <filename>foo.conf</filename> is set up for 3 boot tries. The | |
563 | installer will hence create it under the name <filename>foo+3.conf</filename>. On first boot, the boot loader will | |
564 | rename it to <filename>foo+2-1.conf</filename>. If that boot does not complete successfully, the boot loader will | |
565 | rename it to <filename>foo+1-2.conf</filename> on the following boot. If that fails too, it will finally be renamed | |
566 | <filename>foo+0-3.conf</filename> by the boot loader on next boot, after which it will be considered 'bad'. If the | |
567 | boot succeeds however the entry file will be renamed to <filename>foo.conf</filename> by the OS, so that it is | |
568 | considered 'good' from then on.</para> | |
569 | ||
570 | <para>The boot menu takes the 'tries left' counter into account when sorting the menu entries: entries in 'bad' | |
f65a3326 LP |
571 | state are ordered at the beginning of the list, and entries in 'good' or 'indeterminate' at the end. The user can |
572 | freely choose to boot any entry of the menu, including those already marked 'bad'. If the menu entry to boot is | |
573 | automatically determined, this means that 'good' or 'indeterminate' entries are generally preferred (as the bottom | |
574 | item of the menu is the one booted by default), and 'bad' entries will only be considered if there are no 'good' or | |
2b6cc3ca LP |
575 | 'indeterminate' entries left.</para> |
576 | ||
577 | <para>The <citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry> kernel | |
578 | install framework optionally sets the initial 'tries left' counter to the value specified in | |
579 | <filename>/etc/kernel/tries</filename> when a boot loader entry is first created.</para> | |
580 | </refsect1> | |
581 | ||
941d418d | 582 | <refsect1> |
8fb35004 | 583 | <title>Using <command>systemd-boot</command> in virtual machines</title> |
941d418d GH |
584 | |
585 | <para>When using qemu with OVMF (UEFI Firmware for virtual machines) the <option>-kernel</option> switch | |
586 | works not only for linux kernels, but for any EFI binary, including sd-boot and unified linux | |
8fb35004 | 587 | kernels. Example command line for loading <command>systemd-boot</command> on x64:</para> |
941d418d GH |
588 | |
589 | <para> | |
590 | <command>qemu-system-x86_64 <replaceable>[ ... ]</replaceable> | |
591 | -kernel /usr/lib/systemd/boot/efi/systemd-bootx64.efi</command> | |
592 | </para> | |
593 | ||
594 | <para>systemd-boot will detect that it was started directly instead of being loaded from ESP and will | |
595 | search for the ESP in that case, taking into account boot order information from the hypervisor (if | |
596 | available).</para> | |
597 | </refsect1> | |
598 | ||
f37d3835 ZJS |
599 | <refsect1> |
600 | <title>See Also</title> | |
601 | <para> | |
602 | <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
603 | <citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
2b6cc3ca | 604 | <citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
921fc451 | 605 | <citerefentry><refentrytitle>systemd-boot-random-seed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
2b6cc3ca | 606 | <citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
3f9a615d | 607 | <citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
db811444 | 608 | <ulink url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink>, |
2fe82132 | 609 | <ulink url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink> |
f37d3835 ZJS |
610 | </para> |
611 | </refsect1> | |
612 | </refentry> |