English Portuguese (Brazil)
Use DNF to install kernels whenever possible
Whenever possible, use either the [application]*DNF* or [application]*PackageKit* package manager to install a new kernel because they always *install* a new kernel instead of replacing the current one, which could potentially leave your system unable to boot.
indexterm:[kernel,installing kernel packages] For more information on installing kernel packages with [application]*DNF*, see xref:package-management/DNF.adoc#sec-Updating_Packages[Updating Packages].
Overview of Kernel Packages
indexterm:[kernel,kernel packages]indexterm:[kernel package,kernel,for single, multicore and multiprocessor systems]indexterm:[packages,kernel,for single, multicore and multiprocessor systems]indexterm:[kernel package,kernel-devel,kernel headers and makefiles]indexterm:[packages,kernel-devel,kernel headers and makefiles]indexterm:[kernel package,kernel-headers,C header files files]indexterm:[packages,kernel-headers,C header files files]indexterm:[kernel package,linux-firmware,firmware files]indexterm:[packages,linux-firmware,firmware files]indexterm:[kernel package,perf,firmware files]indexterm:[packages,perf,firmware files] {MAJOROS} contains the following kernel packages:
[package]*kernel* — Contains the kernel for single, multicore and multiprocessor systems.
[package]*kernel-debug* — Contains a kernel with numerous debugging options enabled for kernel diagnosis, at the expense of reduced performance.
[package]*kernel-devel* — Contains the kernel headers and makefiles sufficient to build modules against the [package]*kernel* package.
[package]*kernel-debug-devel* — Contains the development version of the kernel with numerous debugging options enabled for kernel diagnosis, at the expense of reduced performance.
[package]*kernel-headers* — Includes the C header files that specify the interface between the Linux kernel and user-space libraries and programs. The header files define structures and constants that are needed for building most standard programs.
[package]*linux-firmware* — Contains all of the firmware files that are required by various devices to operate.
[package]*perf* — This package contains supporting scripts and documentation for the [application]*perf* tool shipped in each kernel image subpackage.
[package]*kernel-abi-whitelists* — Contains information pertaining to the {MAJOROS} kernel ABI, including a lists of kernel symbols that are needed by external Linux kernel modules and a [package]*dnf* plug-in to aid enforcement.
[package]*kernel-tools* — Contains tools for manipulating the Linux kernel and supporting documentation.
Preparing to Upgrade
indexterm:[boot media]indexterm:[kernel,upgrading,preparing]indexterm:[kernel upgrading,preparing]indexterm:[kernel,upgrading,working boot media] Before upgrading the kernel, it is recommended that you take some precautionary steps.
First, ensure that working boot media exists for the system in case a problem occurs. If the boot loader is not configured properly to boot the new kernel, you can use this media to boot into {MAJOROS}.
USB media often comes in the form of flash devices sometimes called _pen drives_, _thumb disks_, or _keys_, or as an externally-connected hard disk device. Almost all media of this type is formatted as a `VFAT` file system. You can create bootable USB media on media formatted as `ext2`, `ext3`, `ext4`, or `VFAT`.
You can transfer a distribution image file or a minimal boot media image file to USB media. Make sure that sufficient free space is available on the device. Around 4 GB is required for a distribution DVD image, around 700 MB for a distribution CD image, or around 10 MB for a minimal boot media image.
You must have a copy of the `boot.iso` file from a {MAJOROS} installation DVD, or installation CD-ROM#1, and you need a USB storage device formatted with the `VFAT` file system and around 16 MB of free space. The following procedure will not affect existing files on the USB storage device unless they have the same path names as the files that you copy onto it. To create USB boot media, perform the following commands as the `root` user: