Configuring and installing the Linux kernel
Now it's time to build and install a Linux kernel, which is the heart of any Funtoo Linux system. The kernel is loaded by the boot loader, and interfaces directly with your system's hardware, and allows regular (userspace) programs to run.
A kernel must be configured properly for your system's hardware, so that it supports your hard drives, file systems, network cards, and so on. More experienced Linux users can choose to install kernel sources and configure and install their own kernel. If you don't know how to do this, we provide ebuilds that will automatically build a "univeral" kernel, modules and initramfs for booting your system that supports all hardware. This is an extremely simple way of building a kernel that will get your system booted.
What is our goal? To build a kernel that will recognize all the hardware in your system necessary for booting, so that you will be greeted by a friendly login prompt after installation is complete. These instructions will guide you through the process of installing a kernel the "easy" way -- without requiring user configuration, by using a "universal" kernel.
Before we install a kernel, we're going to cover a feature of Portage called package sets. Portage, the package manager/ports system for Funtoo Linux, will keep track of system packages as well as packages you have installed by calling
emerge directly. These packages that are part of the base system are considered part of the "system" package set, while packages that you have installed by typing them on the command line (such as "gnome" in
emerge gnome) will be added to the "world" package set. This provides an easy way to update your entire system.
However, sometimes it's nice to be able to update the kernel all by itself, or leave a kernel update out of your regular whole system update. To do this, we will create a new package set called "kernel".
Kernel Package Set
To create the kernel package set, perform the following steps:
(chroot) # mkdir /etc/portage/sets (chroot) # echo sys-kernel/debian-sources > /etc/portage/sets/kernel
Now, we'll want to set a USE variable to tell
debian-sources to build a "universal" kernel and initramfs for us, to take the guess-work out of getting Funtoo Linux booted. To do this, we're going to set the
binary USE variable for
debian-sources, as follows:
(chroot) # echo "sys-kernel/debian-sources binary" >> /etc/portage/package.use
If USE variables are new to you, you'll be getting a lot more familiar with them as you use Funtoo Linux. At their essence, they are "switches" that you can set to configure options that can be built in to various packages. They're used to customize your Funtoo Linux system to meet your exact needs. We added support for a
binary USE flag to the
debian-sources ebuilds, as well as a few other of our kernel ebuilds, to make it easier for new users to get Funtoo Linux up and running.
Now, when we just want to update our system's packages, we'll type
emerge -auDN @world, and it will update our world set, leaving out the kernel. Likewise, when we just want to update our kernel, we'll type
emerge -au @kernel, and it will update our kernel, leaving out the world set.
Building the Kernel
See Funtoo Linux Kernels for a full list of kernels supported in Funtoo Linux. We recommend
debian-sources for new users.
binary USE flag requires at least 14GB free in
/var/tmp and takes around 1 hour to build on a Intel Core i7 Processor.
Let's emerge our kernel:
(chroot) # emerge -1 @kernel
Right now, the
-1 option is required to not add our
@kernel set to
world-sets. This allows you to emerge it independently from @world. If you forget to use this option, edit
/var/lib/portage/world-sets and remove the
@kernel line. This will prevent kernel updates from being included in @world updates.
Note that while use of the
binary USE flag makes installing a working kernel extremely simple, it is one part of Funtoo Linux that takes a very long time to build from source, because it is building a kernel that supports all hardware that Linux supports! So, get the build started, and then let your machine compile. Slower machines can take up to several hours to build the kernel, and you'll want to make sure that you've set
/etc/portage/make.conf to the number of processing cores/threads (plus one) in your system before starting to build it as quickly as possible -- see the /etc/portage/make.conf section if you forgot to do this.
NVIDIA card users: the
binary USE flag installs the Nouveau drivers which cannot be loaded at the same time as the proprietary drivers, and cannot be unloaded at runtime because of KMS. You need to blacklist it under
For an overview of other kernel options for Funtoo Linux, see Funtoo Linux Kernels. There may be modules that the Debian kernel doesn't include, a situation where genkernel would be useful. Also be sure to see hardware compatibility information.
emerge completes, you'll have a brand new kernel and initramfs installed to
/boot, plus kernel headers installed in
/usr/src/linux, and you'll be ready to configure the boot loader to load these to boot your Funtoo Linux system.