man: document systemd-bless-boot-generator

[thirdparty/systemd.git] / man / systemd-boot.xml

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<refentry id="systemd-boot" conditional='ENABLE_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 graphical menu to select the entry to boot and an editor for the kernel command line. systemd-boot
    supports systems with UEFI firmware only.</para>

    <para>systemd-boot loads boot entry information from the EFI system partition (ESP), usually mounted at
    <filename>/boot</filename>, <filename>/efi</filename>, or <filename>/boot/efi</filename> during OS
    runtime. Configuration file fragments, kernels, initrds and other EFI images to boot generally need to reside on
    the ESP. Linux kernels must be built with <option>CONFIG_EFI_STUB</option> to be able to be directly executed as an
    EFI image. During boot systemd-boot automatically assembles a list of boot entries from the following
    sources:</para>

    <itemizedlist>
      <listitem><para>Boot entries defined with <ulink
      url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader
      Specification</ulink> description files located in <filename>/loader/entries/</filename> on the ESP. These
      usually describe Linux kernel images with associated initrd images, but alternatively may also describe
      arbitrary other EFI executables.</para></listitem>

      <listitem><para>Unified kernel images following the <ulink
      url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader
      Specification</ulink>, as executable EFI binaries in <filename>/EFI/Linux/</filename> on the ESP.
      </para></listitem>

      <listitem><para>The Microsoft Windows EFI boot manager, if installed</para></listitem>

      <listitem><para>The Apple MacOS X 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>
    </itemizedlist>

    <para><citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry> may be
    used to copy kernel images onto the ESP and to generate description files compliant with the Boot Loader
    Specification. <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> may be
    used from a running system to locate the ESP, list available entries, and install systemd-boot itself.</para>

    <para>systemd-boot will provide information about the time spent in UEFI firmware using the <ulink
    url="https://www.freedesktop.org/wiki/Software/systemd/BootLoaderInterface">Boot Loader Interface</ulink>. This
    information can be displayed using
    <citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
    </para>
  </refsect1>

  <refsect1>
    <title>Key bindings</title>
    <para>The following keys may be used in the boot menu:</para>

    <variablelist>
      <varlistentry>
        <term>↑ (Up)</term>
        <term>↓ (Down)</term>
        <term>j</term>
        <term>k</term>
        <term>PageUp</term>
        <term>PageDown</term>
        <term>Home</term>
        <term>End</term>
        <listitem><para>Navigate up/down in the entry list</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>↵ (Enter)</term>
        <listitem><para>Boot selected entry</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>d</term>
        <listitem><para>Make selected entry the default</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>e</term>
        <listitem><para>Edit the kernel command line for selected entry</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>+</term>
        <term>t</term>
        <listitem><para>Increase the timeout before default entry is booted</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>-</term>
        <term>T</term>
        <listitem><para>Decrease the timeout</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>v</term>
        <listitem><para>Show systemd-boot, UEFI, and firmware versions</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>P</term>
        <listitem><para>Print status</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>Q</term>
        <listitem><para>Quit</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>h</term>
        <term>?</term>
        <listitem><para>Show a help screen</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>Ctrl + l</term>
        <listitem><para>Reprint the screen</para></listitem>
      </varlistentry>
    </variablelist>

    <para>The following keys may be used during bootup or in the boot menu to
    directly boot a specific entry:</para>

    <variablelist>
      <varlistentry>
        <term>l</term>
        <listitem><para>Linux</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>w</term>
        <listitem><para>Windows</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>a</term>
        <listitem><para>OS X</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>s</term>
        <listitem><para>EFI shell</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>1</term>
        <term>2</term>
        <term>3</term>
        <term>4</term>
        <term>5</term>
        <term>6</term>
        <term>7</term>
        <term>8</term>
        <term>9</term>
        <listitem><para>Boot entry number 1 … 9</para></listitem>
      </varlistentry>
    </variablelist>

    <para>In the editor, most keys simply insert themselves, but the following keys
    may be used to perform additional actions:</para>

    <variablelist>
      <varlistentry>
        <term>← (Left)</term>
        <term>→ (Right)</term>
        <term>Home</term>
        <term>End</term>
        <listitem><para>Navigate left/right</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>Esc</term>
        <listitem><para>Abort the edit and quit the editor</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>Ctrl + k</term>
        <listitem><para>Clear the command line</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>Ctrl + w</term>
        <term>Alt + Backspace</term>
        <listitem><para>Delete word backwards</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>Alt + d </term>
        <listitem><para>Delete word forwards</para></listitem>
      </varlistentry>

      <varlistentry>
        <term>↵ (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 systemd-boot reads generally reside on the UEFI ESP which is usually mounted to
    <filename>/boot/</filename>, <filename>/efi/</filename> or <filename>/boot/efi</filename> during OS
    runtime. systemd-boot 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>. Boot entry
    description files following the <ulink
    url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader
    Specification</ulink> are read from <filename>/loader/entries/</filename> on the ESP. Unified kernel boot entries
    following the <ulink url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot
    Loader Specification</ulink> are read from <filename>/EFI/Linux/</filename> on the ESP.</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-b6c7-440b29bb8c4</literal>, for communication between the OS and the boot
    loader:</para>

    <variablelist>
      <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>
        <listitem><para>The menu time-out. Read by the boot loader. (Also, modified by it when the
        <keycap>t</keycap>/<keycap>T</keycap> keys are used, 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>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. These variables are defined by the <ulink
        url="https://www.freedesktop.org/wiki/Software/systemd/BootLoaderInterface">Boot Loader
        Interface</ulink>.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <ulink url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink>,
      <ulink url="https://www.freedesktop.org/wiki/Software/systemd/BootLoaderInterface">Boot Loader Interface</ulink>
    </para>
  </refsect1>
</refentry>