kernel-install

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)