How to pick a kernel to boot ?

How to pick a kernel to boot ?

[Lukáš Czerner]

Hi,

I have a simple question about grub2 which I can not find satisfying
answer to.

What is a proper way to pick a kernel to boot from in case I have
multiple kernels installed ? Note that picking the right kernel from
the menu is not an option I do not always have access to the
console.

With grub legacy, this was easy. Simply edit

 /boot/grub/menu.lst

and pick the right number. All the information I need are in that
file.

So what is a recommended way to do this with grub2 ?


Thanks!
-Lukas

Re: How to pick a kernel to boot ?

[Lennart Sorensen]

On Thu, Oct 24, 2013 at 04:46:19PM +0200, Lukáš Czerner wrote:
> Hi,
> 
> I have a simple question about grub2 which I can not find satisfying
> answer to.
> 
> What is a proper way to pick a kernel to boot from in case I have
> multiple kernels installed ? Note that picking the right kernel from
> the menu is not an option I do not always have access to the
> console.
> 
> With grub legacy, this was easy. Simply edit
> 
>  /boot/grub/menu.lst
> 
> and pick the right number. All the information I need are in that
> file.
> 
> So what is a recommended way to do this with grub2 ?

Same thing in /boot/grub/grub.cfg.  There is default with a number.

-- 
Len Sorensen

Re: How to pick a kernel to boot ?

[Prarit Bhargava]

On 10/24/2013 12:44 PM, Lennart Sorensen wrote:
> On Thu, Oct 24, 2013 at 04:46:19PM +0200, Lukáš Czerner wrote:
>> Hi,
>>
>> I have a simple question about grub2 which I can not find satisfying
>> answer to.
>>
>> What is a proper way to pick a kernel to boot from in case I have
>> multiple kernels installed ? Note that picking the right kernel from
>> the menu is not an option I do not always have access to the
>> console.
>>
>> With grub legacy, this was easy. Simply edit
>>
>>  /boot/grub/menu.lst
>>
>> and pick the right number. All the information I need are in that
>> file.
>>
>> So what is a recommended way to do this with grub2 ?
> 
> Same thing in /boot/grub/grub.cfg.  There is default with a number.
> 

Sorry ... some how left the list off my initial reply ...

To set a default to boot, use

grub2-set-default  [kernel entry number]

To boot a kernel once and keep the default the same (ie, boot a kernel one time)

grub2-reboot [kernel entry number]

I've noticed a lot of people messing with /boot/grub2/grub.conf ... you
shouldn't have to do that to select a kernel to boot.

P.

Re: How to pick a kernel to boot ?

[Vladimir 'φ-coder/phcoder' Serbinenko]

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On 24.10.2013 16:46, Lukáš Czerner wrote:
> Hi,
> 
> I have a simple question about grub2 which I can not find satisfying
> answer to.
> 
> What is a proper way to pick a kernel to boot from in case I have
> multiple kernels installed ? Note that picking the right kernel from
> the menu is not an option I do not always have access to the
> console.
> 
> With grub legacy, this was easy. Simply edit
> 
>  /boot/grub/menu.lst
> 
> and pick the right number. All the information I need are in that
> file.
> 
> So what is a recommended way to do this with grub2 ?
> 
You can use numbers but it's a bad idea since they change on update. Use
ids As you see in menuentry:
menuentry ... $menuentry_id_option
'gnulinux-simple-000000000000000000000000000000'
Or
menuentry ... --id 'gnulinux-simple-000000000000000000000000000000'

> 
> Thanks!
> -Lukas
> 
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel
> .
> 



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