[Yum-devel] how to require a kernel module

[Jack Neely]

On Thu, Mar 11, 2010 at 12:56:20PM +0100, Farkas Levente wrote:
> On 03/09/2010 11:55 PM, Jack Neely wrote:
>> On Mon, Mar 08, 2010 at 01:30:34PM +0100, Farkas Levente wrote:
>>> hi,
>>> on rhel/centos-5w we've a lot's of kernel module (thanks to the elrepo)
>>> and we can build our own on a nearly standardized way for rhel/centos.
>>> but i now run into a problem how to add a require kmod line into another
>>> package's spec file. it seems to very easy, if i've got package x.spec:
>>> Requires: y-kmod
>>> first question whether y-kmod or kmod-y (tha package name or the virtual
>>> provides)? and if we go a bit further and have a i386 machine with 4gb
>>> ram which install by default kernel-PAE and like to install x into that
>>> machine i wish to pull (yum pull) kmod-x-PAE and not kmod-x since it
>>> can't be used on a PAE kernel. what's more if x pull kmod-y that also
>>> pull the none PAE kernel too which is also not a good think. there are
>>> two plugins in yum-utils yum-kernel-module and yum-fedorakmod, but none
>>> of the seems to working (yum-fedorakmod instal the proper kmod-x-PAE too
>>> if i set installforallkernels=1, but still install the non PAE one and
>>> the none PAE kernel too).
>>>
>>> so what's the good and proper solution to require y kernel module into
>>> package x (in a way that works with yum on all kernel variant)?
>>>
>>> i even like to modify any of the yum-kernel-module or yum-fedorakmod to
>>> be able to use, but the problem is that i can't write conditional
>>> requires in a package spec file which depend on the runtime kernel
>>> variant:-(
>>>
>>> if there would be some tricky yum plugins which do this:
>>> - if yum needs to install a package
>>> - check whether the package provide kabi-module or kernel-module. if yes
>>> it's a kernel module.
>>> - if it's a kernel module than check the currently running kernel (and
>>> optionally all installed kernel) and install the proper kernel module
>>> variant. eg. if the running kernel is:
>>>    - kernel-2.6.18-164.11.1.el5 then install kmod-ocfs2
>>>    - kernel-PAE-2.6.18-164.11.1.el5 then install kmod-ocfs2-PAE
>>>
>>> anybody has any solution to this?
>>> thanks in advance.
>>> regards.
>>>
>>
>> For RHEL5-ish systems still using the kmod v1 standard, you need to
>> require "foo-kmod".  That's the virtual provides that all the variants
>> should provide.
>>
>> Yum/RPM don't know how to properly dep solve that without the
>> yum-fedorakmod plugin.  Yes, the installforallkernels=1 will make sure
>> that the other matching variants are installed for each kernel.
>>
>> However, if kmod-foo gets in the transaction set, the fedorakmod plugin
>> doesn't know to remove it if the normal kernel package isn't installed.
>> Which probably means the normal kernel package gets sucked into the
>> transaction set as well in some cases.
>
> if you wrote the yum-fedorakmod plugin than you can help me:-)
> in elrepo:
> http://elrepo.org/tiki/tiki-index.php
> we use kabi tracking kernel modules since all rhel kernel are kabi  
> compatible with eachother (which is not true for fedora, but a nice  
> feature in the enterprise target), so don't have to rebuild for each  
> kernel. for the same reason it's not provide "kernel-modules" but  
> provides "kabi-modules".
> the problem
> - even if i require the virtual provides foo-kmod and
> - even if i have installed yum-fedorakmod plugin and
> - even if i only have installed kernel-PAE (ie. not the normal kernel)
> yum still install the kmod-foo (and not only kmod-foo-PAE) and because  
> of this it will pull also the normal kernel too.
> so i'd like to install one such yum plugin which solve this problem and  
> somehow install the proper kernel-variant kmod-foo packages.
>
> can you help me in this? if we can have such a yum plugin it can be add  
> to elrepo so everybody can use it on all rhel/centos where elrepo used.
>
> thanks in advance.
>

I'm sorry, but fedorakmod support the kmod v1 standard which is not the
kabi stuff.  (Although, Red Hat made the kabi packages look just like
the other kmod packages which I didn't really like.)  Jon Masters made
some alterations to the fedorakmod plugin that shipped in RHEL5 in the
yum-kmod package.  I don't know how well those work however.

Jack

-- 
Jack Neely <jjneely at ncsu.edu>
Linux Czar, OIT Campus Linux Services
Office of Information Technology, NC State University
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