| <?xml version='1.0'?> |
| <!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+ --> |
| |
| <refentry id="kernel-install" |
| xmlns:xi="http://www.w3.org/2001/XInclude"> |
| |
| <refentryinfo> |
| <title>kernel-install</title> |
| <productname>systemd</productname> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>kernel-install</refentrytitle> |
| <manvolnum>8</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>kernel-install</refname> |
| <refpurpose>Add and remove kernel and initramfs images to and from /boot</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <cmdsynopsis> |
| <command>kernel-install</command> |
| <arg choice="plain">COMMAND</arg> |
| <arg choice="opt" rep="repeat">OPTIONS</arg> |
| <arg choice="plain"><replaceable>KERNEL-VERSION</replaceable></arg> |
| <arg choice="plain"><replaceable>KERNEL-IMAGE</replaceable></arg> |
| <arg choice="opt" rep="repeat"><replaceable>INITRD-FILE</replaceable></arg> |
| </cmdsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| <para><command>kernel-install</command> is used to install and remove kernel and initramfs images to and |
| from the boot loader partition, referred to as <varname>$BOOT</varname> here. It will usually be one of |
| <filename>/boot</filename>, <filename>/efi</filename>, or <filename>/boot/efi</filename>, see below. |
| </para> |
| |
| <para><command>kernel-install</command> will execute the files |
| located in the directory <filename>/usr/lib/kernel/install.d/</filename> |
| and the local administration directory <filename>/etc/kernel/install.d/</filename>. |
| All files are collectively sorted and executed in lexical order, regardless of the directory in |
| which they live. However, files with identical filenames replace each other. |
| Files in <filename>/etc/kernel/install.d/</filename> take precedence over files with the same name |
| in <filename>/usr/lib/kernel/install.d/</filename>. This can be used to override a system-supplied |
| executables with a local file if needed; a symbolic link in <filename>/etc/kernel/install.d/</filename> |
| with the same name as an executable in <filename>/usr/lib/kernel/install.d/</filename>, |
| pointing to <filename>/dev/null</filename>, disables the executable entirely. Executables must have the |
| extension <literal>.install</literal>; other extensions are ignored.</para> |
| |
| <para>An executable should return <constant>0</constant> on success. It may also |
| return <constant>77</constant> to cause the whole operation to terminate |
| (executables later in lexical order will be skipped).</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Commands</title> |
| <para>The following commands are understood:</para> |
| <variablelist> |
| <varlistentry> |
| <term><command>add <replaceable>KERNEL-VERSION</replaceable> <replaceable>KERNEL-IMAGE</replaceable> [<replaceable>INITRD-FILE</replaceable> ...]</command></term> |
| <listitem> |
| <para>This command expects a kernel version string and a path to a kernel image file as |
| arguments. <command>kernel-install</command> calls the executables from |
| <filename>/usr/lib/kernel/install.d/*.install</filename> and |
| <filename>/etc/kernel/install.d/*.install</filename> with the following arguments: |
| |
| <programlisting>add <replaceable>KERNEL-VERSION</replaceable> <filename>$BOOT/<replaceable>MACHINE-ID</replaceable>/<replaceable>KERNEL-VERSION</replaceable>/</filename> <replaceable>KERNEL-IMAGE</replaceable> [<replaceable>INITRD-FILE</replaceable> ...]</programlisting> |
| </para> |
| |
| <para>Three default plugins execute the following operations in this case:</para> |
| |
| <itemizedlist> |
| <listitem><para><filename>00-entry-directory.install</filename> creates the directory |
| <filename>$BOOT/<replaceable>MACHINE-ID</replaceable>/<replaceable>KERNEL-VERSION</replaceable>/</filename> |
| if <filename>$BOOT/<replaceable>MACHINE-ID</replaceable>/</filename> already exists. |
| </para></listitem> |
| |
| <listitem><para><filename>50-depmod.install</filename> runs |
| <citerefentry><refentrytitle>depmod</refentrytitle><manvolnum>8</manvolnum></citerefentry> for the |
| <replaceable>KERNEL-VERSION</replaceable>.</para></listitem> |
| |
| <listitem><para><filename>90-loaderentry.install</filename> copies <replaceable>KERNEL-IMAGE</replaceable> |
| to |
| <filename>$BOOT/<replaceable>MACHINE-ID</replaceable>/<replaceable>KERNEL-VERSION</replaceable>/linux</filename>. |
| If an <replaceable>INITRD-FILE</replaceable> is provided, it also copies <replaceable>INITRD-FILE</replaceable> |
| to |
| <filename>$BOOT/<replaceable>MACHINE-ID</replaceable>/<replaceable>KERNEL_VERSION</replaceable>/<replaceable>INITRD-FILE</replaceable></filename>. |
| It also creates a boot loader entry according to the <ulink |
| url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink> in |
| <filename>$BOOT/loader/entries/<replaceable>MACHINE-ID</replaceable>-<replaceable>KERNEL-VERSION</replaceable>.conf</filename>. |
| The title of the entry is the <replaceable>PRETTY_NAME</replaceable> parameter specified in |
| <filename>/etc/os-release</filename> or <filename>/usr/lib/os-release</filename> (if the former is |
| missing), or "Linux <replaceable>KERNEL-VERSION</replaceable>", if unset.</para> |
| |
| <para>If the entry directory |
| <filename>$BOOT/<replaceable>MACHINE-ID</replaceable>/<replaceable>KERNEL-VERSION</replaceable>/</filename> |
| does not exist, this plugin does nothing.</para></listitem> |
| </itemizedlist> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><command>remove <replaceable>KERNEL-VERSION</replaceable></command></term> |
| <listitem> |
| <para>This command expects a kernel version string as single argument. This calls executables from |
| <filename>/usr/lib/kernel/install.d/*.install</filename> and |
| <filename>/etc/kernel/install.d/*.install</filename> with the following arguments: |
| |
| <programlisting>remove <replaceable>KERNEL-VERSION</replaceable> <filename>$BOOT/<replaceable>MACHINE-ID</replaceable>/<replaceable>KERNEL-VERSION</replaceable>/</filename></programlisting> |
| </para> |
| |
| <para>Afterwards, <command>kernel-install</command> removes the directory |
| <filename>$BOOT/<replaceable>MACHINE-ID</replaceable>/<replaceable>KERNEL-VERSION</replaceable>/</filename> |
| and its contents.</para> |
| |
| <para>Two default plugins execute the following operations in this case:</para> |
| |
| <itemizedlist> |
| |
| <listitem><para><filename>50-depmod.install</filename> removes the files generated by <command>depmod</command> for this kernel again.</para></listitem> |
| |
| <listitem><para><filename>90-loaderentry.install</filename> removes the file |
| <filename>$BOOT/loader/entries/<replaceable>MACHINE-ID</replaceable>-<replaceable>KERNEL-VERSION</replaceable>.conf</filename>.</para></listitem> |
| </itemizedlist> |
| |
| </listitem> |
| </varlistentry> |
| |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>The <varname>$BOOT</varname> partition</title> |
| <para>The partition where the kernels and <ulink url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot |
| Loader Specification</ulink> snippets are located is called <varname>$BOOT</varname>. |
| <command>kernel-install</command> determines the location of this partition by checking |
| <filename>/efi/</filename>, <filename>/boot/</filename>, and <filename>/boot/efi</filename> |
| in turn. The first location where <filename>$BOOT/loader/entries/</filename> or |
| <filename>$BOOT/$MACHINE_ID/</filename> exists is used.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Options</title> |
| <para>The following options are understood:</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>-v</option></term> |
| <term><option>--verbose</option></term> |
| <listitem> |
| <para>Output additional information about operations being performed.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Environment variables</title> |
| <para>If <option>--verbose</option> is used, <varname>$KERNEL_INSTALL_VERBOSE=1</varname> will be set for |
| the plugins. They may output additional logs in this case.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Exit status</title> |
| <para>If every executable returns 0 or 77, 0 is returned, and a non-zero failure code otherwise.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Files</title> |
| <variablelist> |
| <varlistentry> |
| <term> |
| <filename>/usr/lib/kernel/install.d/*.install</filename> |
| <filename>/etc/kernel/install.d/*.install</filename> |
| </term> |
| <listitem> |
| <para>Drop-in files which are executed by kernel-install.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term> |
| <filename>/etc/kernel/cmdline</filename> |
| <filename>/proc/cmdline</filename> |
| </term> |
| <listitem> |
| <para>Read by <filename>90-loaderentry.install</filename>. The content of the file |
| <filename>/etc/kernel/cmdline</filename> specifies the kernel command line to use. If that file does not |
| exist, <filename>/proc/cmdline</filename> is used.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term> |
| <filename>/etc/kernel/tries</filename> |
| </term> |
| <listitem> |
| <para>Read by <filename>90-loaderentry.install</filename>. If this file exists a numeric value is read from |
| it and the naming of the generated entry file is slightly altered to include it as |
| <filename>$BOOT/loader/entries/<replaceable>MACHINE-ID</replaceable>-<replaceable>KERNEL-VERSION</replaceable>+<replaceable>TRIES</replaceable>.conf</filename>. This |
| is useful for boot loaders such as |
| <citerefentry><refentrytitle>systemd-boot</refentrytitle><manvolnum>7</manvolnum></citerefentry> which |
| implement boot attempt counting with a counter embedded in the entry file name.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term> |
| <filename>/etc/machine-id</filename> |
| </term> |
| <listitem> |
| <para>The content of the file specifies the machine identification <replaceable>MACHINE-ID</replaceable>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term> |
| <filename>/etc/os-release</filename> |
| <filename>/usr/lib/os-release</filename> |
| </term> |
| <listitem> |
| <para>The content of the file specifies the operating system title <replaceable>PRETTY_NAME</replaceable>.</para> |
| </listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para> |
| <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>depmod</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemd-boot</refentrytitle><manvolnum>7</manvolnum></citerefentry>, |
| <ulink url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink> |
| </para> |
| </refsect1> |
| |
| </refentry> |