KERNEL-INSTALL(8) kernel-install KERNEL-INSTALL(8)
NAME
kernel-install - Add and remove kernel and initramfs images to and from
/boot
SYNOPSIS
kernel-install COMMAND [OPTIONS...] KERNEL-VERSION KERNEL-IMAGE
[INITRD-FILE...]
DESCRIPTION
kernel-install is used to install and remove kernel and initramfs
images to and from the boot loader partition, referred to as $BOOT
here. It will usually be one of /boot, /efi, or /boot/efi, see below.
kernel-install will execute the files located in the directory
/usr/lib/kernel/install.d/ and the local administration directory
/etc/kernel/install.d/. 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
/etc/kernel/install.d/ take precedence over files with the same name in
/usr/lib/kernel/install.d/. This can be used to override a
system-supplied executables with a local file if needed; a symbolic
link in /etc/kernel/install.d/ with the same name as an executable in
/usr/lib/kernel/install.d/, pointing to /dev/null, disables the
executable entirely. Executables must have the extension ".install";
other extensions are ignored.
An executable should return 0 on success. It may also return 77 to
cause the whole operation to terminate (executables later in lexical
order will be skipped).
COMMANDS
The following commands are understood:
add KERNEL-VERSION KERNEL-IMAGE [INITRD-FILE ...]
This command expects a kernel version string and a path to a kernel
image file as arguments. kernel-install calls the executables from
/usr/lib/kernel/install.d/*.install and
/etc/kernel/install.d/*.install with the following arguments:
add KERNEL-VERSION $BOOT/MACHINE-ID/KERNEL-VERSION/ KERNEL-IMAGE [INITRD-FILE ...]
Three default plugins execute the following operations in this
case:
o 00-entry-directory.install creates the directory
$BOOT/MACHINE-ID/KERNEL-VERSION/ if $BOOT/MACHINE-ID/ already
exists.
o 50-depmod.install runs depmod(8) for the KERNEL-VERSION.
o 90-loaderentry.install copies KERNEL-IMAGE to
$BOOT/MACHINE-ID/KERNEL-VERSION/linux. If an INITRD-FILE is
provided, it also copies INITRD-FILE to
$BOOT/MACHINE-ID/KERNEL_VERSION/INITRD-FILE. It also creates a
boot loader entry according to the Boot Loader Specification[1]
in $BOOT/loader/entries/MACHINE-ID-KERNEL-VERSION.conf. The
title of the entry is the PRETTY_NAME parameter specified in
/etc/os-release or /usr/lib/os-release (if the former is
missing), or "Linux KERNEL-VERSION", if unset.
If the entry directory $BOOT/MACHINE-ID/KERNEL-VERSION/ does
not exist, this plugin does nothing.
remove KERNEL-VERSION
This command expects a kernel version string as single argument.
This calls executables from /usr/lib/kernel/install.d/*.install and
/etc/kernel/install.d/*.install with the following arguments:
remove KERNEL-VERSION $BOOT/MACHINE-ID/KERNEL-VERSION/
Afterwards, kernel-install removes the directory
$BOOT/MACHINE-ID/KERNEL-VERSION/ and its contents.
Two default plugins execute the following operations in this case:
o 50-depmod.install removes the files generated by depmod for
this kernel again.
o 90-loaderentry.install removes the file
$BOOT/loader/entries/MACHINE-ID-KERNEL-VERSION.conf.
THE $BOOT PARTITION
The partition where the kernels and Boot Loader Specification[1]
snippets are located is called $BOOT. kernel-install determines the
location of this partition by checking /efi/, /boot/, and /boot/efi in
turn. The first location where $BOOT/loader/entries/ or
$BOOT/$MACHINE_ID/ exists is used.
OPTIONS
The following options are understood:
-v, --verbose
Output additional information about operations being performed.
-h, --help
Print a short help text and exit.
ENVIRONMENT VARIABLES
If --verbose is used, $KERNEL_INSTALL_VERBOSE=1 will be set for the
plugins. They may output additional logs in this case.
EXIT STATUS
If every executable returns 0 or 77, 0 is returned, and a non-zero
failure code otherwise.
FILES
/usr/lib/kernel/install.d/*.install /etc/kernel/install.d/*.install
Drop-in files which are executed by kernel-install.
/etc/kernel/cmdline /proc/cmdline
Read by 90-loaderentry.install. The content of the file
/etc/kernel/cmdline specifies the kernel command line to use. If
that file does not exist, /proc/cmdline is used.
/etc/kernel/tries
Read by 90-loaderentry.install. 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
$BOOT/loader/entries/MACHINE-ID-KERNEL-VERSION+TRIES.conf. This is
useful for boot loaders such as systemd-boot(7) which implement
boot attempt counting with a counter embedded in the entry file
name.
/etc/machine-id
The content of the file specifies the machine identification
MACHINE-ID.
/etc/os-release /usr/lib/os-release
The content of the file specifies the operating system title
PRETTY_NAME.
SEE ALSO
machine-id(5), os-release(5), depmod(8), systemd-boot(7), Boot Loader
Specification[1]
NOTES
1. Boot Loader Specification
https://systemd.io/BOOT_LOADER_SPECIFICATION
systemd 245 KERNEL-INSTALL(8)