Yum kernel upgrades don't boot

[Bill Davidsen]

Kevin Fenzi wrote:
> On Sat, 18 May 2013 19:35:23 -0700
> Joe Zeff <joe at zeff.us> wrote:
>
>> On 05/18/2013 06:40 PM, Bill Davidsen wrote:
>>>
>>>
>>> So is dropping the kernel command line options a bug, or deliberate
>>> policy?
>>
>> Neither.  When you install a new kernel, the file is rebuilt, using
>> /etc/default/grub as a template.  If you need to add something
>> permanently, you need to add it there.
>
> It's actually not. ;) Kernel updates don't run grub2-mkconfig, they use
> grubby which just copies the last existing entry.
>
> It should re-use the options from the previous top existing kernel. Did
> you have those options in that kernel entry?
>
The fact that I got three different answers tells me that I'm not alone in 
having some questions in this area.

Reindl says he has never seen grub2 touched, then adds that the params of the 
running kernel were used for the new one. That's useful if true, I have assumed 
that the parameters of the default kernel (the "Fedora" one) were used. In cases 
where the running kernel was booted after an edit, I assume that means they are 
taken from /proc/cmnline.

Joe Zeff says the list is rebuilt using /etc/default/grub, while Kevin says it 
is NOT rebuilt, but copied from "the previous top existing kernel" which might 
mean the kernel in the "Advanced" submenu rather than the "Fedora" kernel. If 
that's the case then I have to edit grub2.conf each time for every kernel even 
though I don't normally boot them, and they don't all have the same options. 
Some of the kernels I have never got the vendor video module, and have to run 
with the vesa driver, so options are unique, PITA to hand edit.

Lastly, there is an /etc/default/grub2 file, don't know what created that, but 
it appears to be irrelevant.

Thank you all for your responses, although they don't give me clarity they give 
me things I can observe while I do my own testing. Need I add that this area 
seems to be a good one for some definitive documentation?

"We are still confused, but about new and more important things."


During upgrade I get "Found {version}" messages, which I thought were from 
grub2-mkconfig.

-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot