| <?xml version='1.0'?> <!--*-nxml-*--> |
| <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
| "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
| <!-- SPDX-License-Identifier: LGPL-2.1-or-later --> |
| |
| <refentry id="systemd-boot" conditional='HAVE_GNU_EFI' |
| xmlns:xi="http://www.w3.org/2001/XInclude"> |
| <refentryinfo> |
| <title>systemd-boot</title> |
| <productname>systemd</productname> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>systemd-boot</refentrytitle> |
| <manvolnum>7</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>systemd-boot</refname> |
| <refname>sd-boot</refname> |
| <refpurpose>A simple UEFI boot manager</refpurpose> |
| </refnamediv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para><command>systemd-boot</command> (short: <command>sd-boot</command>) is a simple UEFI boot |
| manager. It provides a textual menu to select the entry to boot and an editor for the kernel command |
| line. <command>systemd-boot</command> supports systems with UEFI firmware only.</para> |
| |
| <para><command>systemd-boot</command> loads boot entry information from the EFI system partition (ESP), |
| usually mounted at <filename>/efi/</filename>, <filename>/boot/</filename>, or |
| <filename>/boot/efi/</filename> during OS runtime, as well as from the Extended Boot Loader partition |
| (XBOOTLDR) if it exists (usually mounted to <filename>/boot/</filename>). Configuration file fragments, |
| kernels, initrds and other EFI images to boot generally need to reside on the ESP or the Extended Boot |
| Loader partition. Linux kernels must be built with <option>CONFIG_EFI_STUB</option> to be able to be |
| directly executed as an EFI image. During boot <command>systemd-boot</command> automatically assembles a |
| list of boot entries from the following sources:</para> |
| |
| <itemizedlist> |
| <listitem><para>Boot entries defined with <ulink |
| url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink> Type #1 |
| description files located in <filename>/loader/entries/</filename> on the ESP and the Extended Boot |
| Loader Partition. These usually describe Linux kernel images with associated initrd images, but |
| alternatively may also describe other arbitrary EFI executables.</para></listitem> |
| |
| <listitem><para>Unified kernel images, <ulink url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot |
| Loader Specification</ulink> Type #2, which are executable EFI binaries in |
| <filename>/EFI/Linux/</filename> on the ESP and the Extended Boot Loader Partition.</para></listitem> |
| |
| <listitem><para>The Microsoft Windows EFI boot manager, if installed.</para></listitem> |
| |
| <listitem><para>The Apple macOS boot manager, if installed.</para></listitem> |
| |
| <listitem><para>The EFI Shell binary, if installed.</para></listitem> |
| |
| <listitem><para>A reboot into the UEFI firmware setup option, if supported by the firmware.</para></listitem> |
| |
| <listitem><para>Secure Boot variables enrollment if the UEFI firmware is in setup-mode and files are provided |
| on the ESP.</para></listitem> |
| </itemizedlist> |
| |
| <para><command>systemd-boot</command> supports the following features:</para> |
| |
| <itemizedlist> |
| <listitem><para>Basic boot manager configuration changes (such as timeout |
| configuration, default boot entry selection, …) may be made directly from the boot loader UI at |
| boot-time, as well as during system runtime with EFI variables.</para></listitem> |
| |
| <listitem><para>The boot manager integrates with the <command>systemctl</command> command to implement |
| features such as <command>systemctl reboot --boot-loader-entry=…</command> (for rebooting into a |
| specific boot menu entry, i.e. "reboot into Windows") and <command>systemctl reboot |
| --boot-loader-menu=…</command> (for rebooting into the boot loader menu), by implementing the <ulink |
| url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>. See |
| <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for |
| details.</para></listitem> |
| |
| <listitem><para>An EFI variable set by the boot loader informs the OS about the EFI System Partition used |
| during boot. This is then used to automatically mount the correct EFI System Partition to |
| <filename>/efi/</filename> or <filename>/boot/</filename> during OS runtime. See |
| <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| for details.</para></listitem> |
| |
| <listitem><para>The boot manager provides information about the boot time spent in UEFI firmware using |
| the <ulink url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>. This |
| information can be displayed using |
| <citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry>. |
| </para></listitem> |
| |
| <listitem><para>The boot manager implements boot counting and automatic fallback to older, working boot |
| entries on failure. See <ulink url="https://systemd.io/AUTOMATIC_BOOT_ASSESSMENT">Automatic Boot |
| Assessment</ulink>.</para></listitem> |
| |
| <listitem><para>The boot manager optionally reads a random seed from the ESP partition, combines it |
| with a 'system token' stored in a persistent EFI variable and derives a random seed to use by the OS as |
| entropy pool initialization, providing a full entropy pool during early boot.</para></listitem> |
| |
| <listitem><para>The boot manager allows for Secure Boot variables to be enrolled if the UEFI firmware is |
| in setup-mode. Additionally, variables can be automatically enrolled if configured.</para></listitem> |
| </itemizedlist> |
| |
| <para><citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| may be used from a running system to locate the ESP and the Extended Boot Loader Partition, list |
| available entries, and install <command>systemd-boot</command> itself.</para> |
| |
| <para><citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| may be used to copy kernel images onto the ESP or the Extended Boot Loader Partition and to generate |
| description files compliant with the Boot Loader |
| Specification.</para> |
| |
| <para><citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| may be used as UEFI boot stub for executed kernels, which is useful to show graphical boot splashes |
| before transitioning into the Linux world. It is also capable of automatically picking up auxiliary |
| credential files (for boot parameterization) and system extension images, as companion files to the |
| booted kernel images.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Key bindings</title> |
| <para>The following keys may be used in the boot menu:</para> |
| |
| <!-- Developer commands Q/v/Ctrl+l deliberately not advertised. --> |
| |
| <variablelist> |
| <varlistentry> |
| <term><keycap>↑</keycap> (Up)</term> |
| <term><keycap>↓</keycap> (Down)</term> |
| <term><keycap>j</keycap></term> |
| <term><keycap>k</keycap></term> |
| <term><keycap>PageUp</keycap></term> |
| <term><keycap>PageDown</keycap></term> |
| <term><keycap>Home</keycap></term> |
| <term><keycap>End</keycap></term> |
| <listitem><para>Navigate up/down in the entry list</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>↵</keycap> (Enter)</term> |
| <term><keycap>→</keycap> (Right)</term> |
| <listitem><para>Boot selected entry</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>d</keycap></term> |
| <listitem><para>Make selected entry the default</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>e</keycap></term> |
| <listitem><para>Edit the kernel command line for selected entry</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>+</keycap></term> |
| <term><keycap>t</keycap></term> |
| <listitem><para>Increase the timeout before default entry is booted</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>-</keycap></term> |
| <term><keycap>T</keycap></term> |
| <listitem><para>Decrease the timeout</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>r</keycap></term> |
| <listitem><para>Change screen resolution, skipping any unsupported modes.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>R</keycap></term> |
| <listitem><para>Reset screen resolution to firmware or configuration file default.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>p</keycap></term> |
| <listitem><para>Print status</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>h</keycap></term> |
| <term><keycap>?</keycap></term> |
| <term><keycap>F1</keycap></term> |
| <listitem><para>Show a help screen</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>f</keycap></term> |
| <listitem><para>Reboot into firmware interface.</para> |
| |
| <para>For compatibility with the keybindings of several firmware implementations this operation |
| may also be reached with <keycap>F2</keycap>, <keycap>F10</keycap>, <keycap>Del</keycap> and |
| <keycap>Esc</keycap>.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <para>The following keys may be pressed during bootup or in the boot menu to directly boot a specific |
| entry:</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><keycap>l</keycap></term> |
| <listitem><para>Linux</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>w</keycap></term> |
| <listitem><para>Windows</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>a</keycap></term> |
| <listitem><para>macOS</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>s</keycap></term> |
| <listitem><para>EFI shell</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>1</keycap></term> |
| <term><keycap>2</keycap></term> |
| <term><keycap>3</keycap></term> |
| <term><keycap>4</keycap></term> |
| <term><keycap>5</keycap></term> |
| <term><keycap>6</keycap></term> |
| <term><keycap>7</keycap></term> |
| <term><keycap>8</keycap></term> |
| <term><keycap>9</keycap></term> |
| <listitem><para>Boot entry number 1 … 9</para></listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <para>The boot menu is shown when a non-zero menu timeout has been configured. If the menu timeout has |
| been set to zero, it is sufficient to press any key — before the boot loader initializes — to bring up |
| the boot menu, except for the keys listed immediately above as they directly boot into the selected boot |
| menu item. Note that depending on the firmware implementation the time window where key presses are |
| accepted before the boot loader initializes might be short. If the window is missed, reboot and try |
| again, possibly pressing a suitable key (e.g. the space bar) continuously; on most systems it should be |
| possible to hit the time window after a few attempts. To avoid this problem, consider setting a non-zero |
| timeout, thus showing the boot menu unconditionally. Some desktop environments might offer an option to |
| directly boot into the boot menu, to avoid the problem altogether. Alternatively, use the command line |
| <command>systemctl reboot --boot-loader-menu=0</command> from the shell.</para> |
| |
| <para>In the editor, most keys simply insert themselves, but the following keys |
| may be used to perform additional actions:</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><keycap>←</keycap> (Left)</term> |
| <term><keycap>→</keycap> (Right)</term> |
| <term><keycap>Home</keycap></term> |
| <term><keycap>End</keycap></term> |
| <listitem><para>Navigate left/right</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>Esc</keycap></term> |
| <term><keycombo><keycap>Ctrl</keycap><keycap>c</keycap></keycombo></term> |
| <listitem><para>Abort the edit and quit the editor</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycombo><keycap>Ctrl</keycap><keycap>k</keycap></keycombo></term> |
| <listitem><para>Clear the command line forwards</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycombo><keycap>Ctrl</keycap><keycap>w</keycap></keycombo></term> |
| <term><keycombo><keycap>Alt</keycap><keycap>Backspace</keycap></keycombo></term> |
| <listitem><para>Delete word backwards</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycombo><keycap>Ctrl</keycap><keycap>Del</keycap></keycombo></term> |
| <term><keycombo><keycap>Alt</keycap><keycap>d</keycap></keycombo></term> |
| <listitem><para>Delete word forwards</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><keycap>↵</keycap> (Enter)</term> |
| <listitem><para>Boot entry with the edited command line</para></listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <para>Note that unless configured otherwise in the UEFI firmware, systemd-boot will |
| use the US keyboard layout, so key labels might not match for keys like +/-. |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Files</title> |
| |
| <para>The files <command>systemd-boot</command> processes generally reside on the UEFI ESP which is |
| usually mounted to <filename>/efi/</filename>, <filename>/boot/</filename> or |
| <filename>/boot/efi/</filename> during OS runtime. It also processes files on the Extended Boot Loader |
| partition which is typically mounted to <filename>/boot/</filename>, if it |
| exists.</para> |
| |
| <para><command>systemd-boot</command> reads runtime configuration such as the boot timeout and default |
| entry from <filename>/loader/loader.conf</filename> on the ESP (in combination with data read from EFI |
| variables). See |
| <citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> |
| |
| <para>Boot entry description files following the <ulink |
| url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink> are read from |
| <filename>/loader/entries/</filename> on the ESP and the Extended Boot Loader partition.</para> |
| |
| <para>Unified kernel boot entries following the <ulink |
| url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink> are read from |
| <filename>/EFI/Linux/</filename> on the ESP and the Extended Boot Loader partition.</para> |
| |
| <para>Optionally, a random seed for early boot entropy pool provisioning is stored in |
| <filename>/loader/random-seed</filename> in the ESP.</para> |
| |
| <para>During initialization, <command>sd-boot</command> automatically loads all driver files placed in |
| the <filename>/EFI/systemd/drivers/</filename> directory of the ESP. The files placed there must have an |
| extension of the EFI architecture ID followed by <filename>.efi</filename> (e.g. for x86-64 this means a |
| suffix of <filename>x64.efi</filename>). This may be used to automatically load file system drivers and |
| similar, to extend the native firmware support.</para> |
| |
| <para>Enrollment of Secure Boot variables can be performed manually or automatically if files are available |
| under <filename>/loader/keys/<replaceable>NAME</replaceable>/{db,KEK,PK}.auth</filename>, <replaceable>NAME</replaceable> |
| being the display name for the set of variables in the menu. If one of the sets is named <filename>auto</filename> |
| then it might be enrolled automatically depending on whether <literal>secure-boot-enroll</literal> is set |
| to force or not.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>EFI Variables</title> |
| |
| <para>The following EFI variables are defined, set and read by <command>systemd-boot</command>, under the |
| vendor UUID <literal>4a67b082-0a4c-41cf-b6c7-440b29bb8c4f</literal>, for communication between the boot |
| loader and the OS:</para> |
| |
| <variablelist class='efi-variables'> |
| <varlistentry> |
| <term><varname>LoaderBootCountPath</varname></term> |
| <listitem><para>If boot counting is enabled, contains the path to the file in whose name the boot counters are |
| encoded. Set by the boot |
| loader. <citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| uses this information to mark a boot as successful as determined by the successful activation of the |
| <filename>boot-complete.target</filename> target unit.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderConfigTimeout</varname></term> |
| <term><varname>LoaderConfigTimeoutOneShot</varname></term> |
| <listitem><para>The menu timeout in seconds. Read by the boot loader. <varname>LoaderConfigTimeout</varname> |
| is maintained persistently, while <varname>LoaderConfigTimeoutOneShot</varname> is a one-time override which is |
| read once (in which case it takes precedence over <varname>LoaderConfigTimeout</varname>) and then |
| removed. <varname>LoaderConfigTimeout</varname> may be manipulated with the |
| <keycap>t</keycap>/<keycap>T</keycap> keys, see above.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderDevicePartUUID</varname></term> |
| |
| <listitem><para>Contains the partition UUID of the EFI System Partition the boot loader was run from. Set by |
| the boot |
| loader. <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| uses this information to automatically find the disk booted from, in order to discover various other partitions |
| on the same disk automatically.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderEntries</varname></term> |
| |
| <listitem><para>A list of the identifiers of all discovered boot loader entries. Set by the boot |
| loader.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderEntryDefault</varname></term> |
| <term><varname>LoaderEntryOneShot</varname></term> |
| |
| <listitem><para>The identifier of the default boot loader entry. Set primarily by the OS and read by the boot |
| loader. <varname>LoaderEntryOneShot</varname> sets the default entry for the next boot only, while |
| <varname>LoaderEntryDefault</varname> sets it persistently for all future |
| boots. <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s |
| <option>set-default</option> and <option>set-oneshot</option> commands make use of these variables. The boot |
| loader modifies <varname>LoaderEntryDefault</varname> on request, when the <keycap>d</keycap> key is used, see |
| above.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderEntrySelected</varname></term> |
| |
| <listitem><para>The identifier of the boot loader entry currently being booted. Set by the boot |
| loader.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderFeatures</varname></term> |
| |
| <listitem><para>A set of flags indicating the features the boot loader supports. Set by the boot loader. Use |
| <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this |
| data.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderFirmwareInfo</varname></term> |
| <term><varname>LoaderFirmwareType</varname></term> |
| |
| <listitem><para>Brief firmware information. Set by the boot loader. Use |
| <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this |
| data.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderImageIdentifier</varname></term> |
| |
| <listitem><para>The path of executable of the boot loader used for the current boot, relative to the EFI System |
| Partition's root directory. Set by the boot loader. Use |
| <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this |
| data.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderInfo</varname></term> |
| |
| <listitem><para>Brief information about the boot loader. Set by the boot loader. Use |
| <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this |
| data.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderTimeExecUSec</varname></term> |
| <term><varname>LoaderTimeInitUSec</varname></term> |
| <term><varname>LoaderTimeMenuUsec</varname></term> |
| |
| <listitem><para>Information about the time spent in various parts of the boot loader. Set by the boot |
| loader. Use <citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| to view this data. </para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>LoaderSystemToken</varname></term> |
| |
| <listitem><para>A binary random data field, that is used for generating the random seed to pass to |
| the OS (see above). Note that this random data is generally only generated once, during OS |
| installation, and is then never updated again.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| |
| <para>Many of these variables are defined by the <ulink |
| url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Boot Counting</title> |
| |
| <para><command>systemd-boot</command> implements a simple boot counting mechanism on top of the <ulink |
| url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink>, for automatic and unattended |
| fallback to older kernel versions/boot loader entries when a specific entry continuously fails. Any boot loader |
| entry file and unified kernel image file that contains a <literal>+</literal> followed by one or two numbers (if |
| two they need to be separated by a <literal>-</literal>), before the <filename>.conf</filename> or |
| <filename>.efi</filename> suffix is subject to boot counting: the first of the two numbers ('tries left') is |
| decreased by one on every boot attempt, the second of the two numbers ('tries done') is increased by one (if 'tries |
| done' is absent it is considered equivalent to 0). Depending on the current value of these two counters the boot |
| entry is considered to be in one of three states:</para> |
| |
| <orderedlist> |
| <listitem><para>If the 'tries left' counter of an entry is greater than zero the entry is considered to be in |
| 'indeterminate' state. This means the entry has not completed booting successfully yet, but also hasn't been |
| determined not to work.</para></listitem> |
| |
| <listitem><para>If the 'tries left' counter of an entry is zero it is considered to be in 'bad' state. This means |
| no further attempts to boot this item will be made (that is, unless all other boot entries are also in 'bad' |
| state), as all attempts to boot this entry have not completed successfully.</para></listitem> |
| |
| <listitem><para>If the 'tries left' and 'tries done' counters of an entry are absent it is considered to be in |
| 'good' state. This means further boot counting for the entry is turned off, as it successfully booted at least |
| once. The |
| <citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| service moves the currently booted entry from 'indeterminate' into 'good' state when a boot attempt completed |
| successfully.</para></listitem> |
| </orderedlist> |
| |
| <para>Generally, when new entries are added to the boot loader, they first start out in 'indeterminate' state, |
| i.e. with a 'tries left' counter greater than zero. The boot entry remains in this state until either it managed to |
| complete a full boot successfully at least once (in which case it will be in 'good' state) — or the 'tries left' |
| counter reaches zero (in which case it will be in 'bad' state).</para> |
| |
| <para>Example: let's say a boot loader entry file <filename>foo.conf</filename> is set up for 3 boot tries. The |
| installer will hence create it under the name <filename>foo+3.conf</filename>. On first boot, the boot loader will |
| rename it to <filename>foo+2-1.conf</filename>. If that boot does not complete successfully, the boot loader will |
| rename it to <filename>foo+1-2.conf</filename> on the following boot. If that fails too, it will finally be renamed |
| <filename>foo+0-3.conf</filename> by the boot loader on next boot, after which it will be considered 'bad'. If the |
| boot succeeds however the entry file will be renamed to <filename>foo.conf</filename> by the OS, so that it is |
| considered 'good' from then on.</para> |
| |
| <para>The boot menu takes the 'tries left' counter into account when sorting the menu entries: entries in 'bad' |
| state are ordered at the beginning of the list, and entries in 'good' or 'indeterminate' at the end. The user can |
| freely choose to boot any entry of the menu, including those already marked 'bad'. If the menu entry to boot is |
| automatically determined, this means that 'good' or 'indeterminate' entries are generally preferred (as the bottom |
| item of the menu is the one booted by default), and 'bad' entries will only be considered if there are no 'good' or |
| 'indeterminate' entries left.</para> |
| |
| <para>The <citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry> kernel |
| install framework optionally sets the initial 'tries left' counter to the value specified in |
| <filename>/etc/kernel/tries</filename> when a boot loader entry is first created.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Using systemd-boot in virtual machines.</title> |
| |
| <para>When using qemu with OVMF (UEFI Firmware for virtual machines) the <option>-kernel</option> switch |
| works not only for linux kernels, but for any EFI binary, including sd-boot and unified linux |
| kernels. Example command line for loading sd-boot on x64:</para> |
| |
| <para> |
| <command>qemu-system-x86_64 <replaceable>[ ... ]</replaceable> |
| -kernel /usr/lib/systemd/boot/efi/systemd-bootx64.efi</command> |
| </para> |
| |
| <para>systemd-boot will detect that it was started directly instead of being loaded from ESP and will |
| search for the ESP in that case, taking into account boot order information from the hypervisor (if |
| available).</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para> |
| <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd-boot-random-seed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| <ulink url="https://uapi-group.org/specifications/specs/boot_loader_specification">Boot Loader Specification</ulink>, |
| <ulink url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink> |
| </para> |
| </refsect1> |
| </refentry> |
