Modular Kernel Packaging for Cloud

[Bruno Wolff III]

On Fri, Mar 14, 2014 at 16:42:11 +0900,
   "Sandro \"red\" Mathys" <red at fedoraproject.org> wrote:
>
>Okay, I poked around in the yum source, yum docs and kernel packages a
>bit. So yum (and some testing confirms, dnf too) does not check the
>package names but the provides (obviously, thinking about it). The
>actual magic being that both kernel and kernel-core provide "kernel".
>If that is still the case once the patch is merged from copr to
>Fedora, no changes to yum or dnf should become necessary. Which would
>probably leave us with "anaconda must allow for installing only just
>kernel-core instead of kernel (when kickstarting)" as the only
>necessary change to Fedora. I guess.

The behavior is controlled by the installonlypkgs setting in yum.conf. 
 From the man page:

  installonlypkgs  List  of package provides that should only ever
               be installed, never updated.  Kernels in  particular  fall  into
               this  category. Defaults to kernel, kernel-bigmem, kernel-enter‐
               prise, kernel-smp, kernel-modules,  kernel-debug,  kernel-unsup‐
               ported,  kernel-source,  kernel-devel,  kernel-PAE,  kernel-PAE-
               debug.

I believe kernel-modules-extra also got added to the default relatively 
recently. But that change doesn't seem to have made it to the documentation.
(That package provides installonlypkgs(kernel-module), so there might 
be some extra magic related to that provide.)