Fedora 24 - Grub2 permanent cmdline changes

[Earl Ramirez]

Good day All,

Recently I have performed a clean install of Fedora 24 and I will like
to make some persistent changes to grub2, in the past (Fedora 23) I
would modify /etc/sysconfig/grub and append the changes to the
GRUB_CMDLINE and run grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg
and I would be okay. However when I try to get /etc/sysconfig/grub
which is a symbolic link to /etc/default/grub I no long see the options
to make the changes, Instead I see this content in both
/etc/default/grub

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
set pager=1

if [ -s $prefix/grubenv ]; then
  load_env
fi
if [ "${next_entry}" ] ; then
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
else
   set default="${saved_entry}"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else

**snip**

I have checked the F24 docs on modify grub2 and I see that it still
advise on editing GRUB_CMDLINE from /etc/sysconfig/grub.

Can someone shed some light on making persistent changes to the grub
cmdline on F24.

Thanks in advance.

[Tom Horsley]

On Thu, 07 Jul 2016 10:45:30 +0800
Earl Ramirez wrote:
> run grub2-mkconfig

As near as I can tell, absolutely nothing ever runs
the grub2-mkconfig program, so unless you run it yourself
you can make permanent changes by simply editing the
grub.cfg file directly.

When dnf installs a new kernel, it simply looks at
the existing kernel lines in grub.cfg and copies the
same options to the new kernel line (or the "grubby"
program it runs does that).

[Edouard Fazenda]

Hi Earl,

On Fedora 24 it's the same configuration as Fedora 23, you have to edit
/etc/default/grub file and after run the grub2-mkconfig command to update
the grub.cfg Configuration file in /boot. Make sure that the symbolic link
of /etc/sysconfig/grub is still pointing to /etc/default/grub file.

Cheers, Edouard.

2016-07-07 14:51 GMT+02:00 Tom Horsley :
> On Thu, 07 Jul 2016 10:45:30 +0800
> Earl Ramirez wrote:
> > run grub2-mkconfig
>
> As near as I can tell, absolutely nothing ever runs
> the grub2-mkconfig program, so unless you run it yourself
> you can make permanent changes by simply editing the
> grub.cfg file directly.
>
> When dnf installs a new kernel, it simply looks at
> the existing kernel lines in grub.cfg and copies the
> same options to the new kernel line (or the "grubby"
> program it runs does that).
> --
> users mailing list
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[Stephen Morris]

On 08/07/16 02:07, Edouard Fazenda wrote:
> Hi Earl,
>
> On Fedora 24 it's the same configuration as Fedora 23, you have to 
> edit /etc/default/grub file and after run the grub2-mkconfig command 
> to update the grub.cfg Configuration file in /boot. Make sure that the 
> symbolic link of /etc/sysconfig/grub is still pointing to 
> /etc/default/grub file.
>
> Cheers, Edouard.

Hi Earl, just following on from what Edouard said, I have never used 
/etc/sysconfig/grub to make grub changes, as until your thread I didn't 
know it existed. All the grub documentation I have seen has said to make 
changed directly to /etc/default/grub, which is what I have always done. 
Like Tom and you have both indicated I have always run 
grub2-mkconfig/grub2-install manually because I don't like the format of 
the grub menu built by grubby (which is automatically run when a new 
kernel is installed as Tom said). Also as I understand it, grubby does 
not use /etc/default/grub to build its grub menus.

From what you have shown in your thread it looks like 
/etc/sysconfig/grub is linked to the wrong file. It seems to be linked 
to /etc/grub.d/00-header, so you may want to re-link it back to 
/etc/default/grub. I have checked on my F24 system and 
/etc/sysconfig/grub is a link to /etc/default/grub.

regards,
Steve
> 2016-07-07 14:51 GMT+02:00 Tom Horsley <[e-mail] 
> >:
> On Thu, 07 Jul 2016 10:45:30 +0800
> Earl Ramirez wrote:
>
> > run grub2-mkconfig
>
> As near as I can tell, absolutely nothing ever runs
> the grub2-mkconfig program, so unless you run it yourself
> you can make permanent changes by simply editing the
> grub.cfg file directly.
>
> When dnf installs a new kernel, it simply looks at
> the existing kernel lines in grub.cfg and copies the
> same options to the new kernel line (or the "grubby"
> program it runs does that).
> --
> users mailing list
> [e-mail] <mailto:[e-mail]>
> To unsubscribe or change subscription options:
> https://lists.fedoraproject.org/admin/lists/[e-mail]
> Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
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> Have a question? Ask away: http://ask.fedoraproject.org
>
>
>
>
> -- 
> ________________________________________
> Edouard Fazenda
> Tel : [phone]
>
> --
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[Rami Rosen]

Hi, all,
> I have checked on my F24 system and /etc/sysconfig/grub is a link to /etc/default/grub.

The same with me, on a fresh instalattion of Fedora 24:
ls /etc/sysconfig/grub -al
lrwxrwxrwx. 1 root root 17 Jun 10 21:31 /etc/sysconfig/grub -> /etc/default/grub

Regards,
Rami Rosen

[Earl Ramirez]

On 8 July 2016 at 06:03, Stephen Morris  wrote:
> On 08/07/16 02:07, Edouard Fazenda wrote:
> > Hi Earl,
> >
> > On Fedora 24 it's the same configuration as Fedora 23, you have to edit
> > /etc/default/grub file and after run the grub2-mkconfig command to update
> > the grub.cfg Configuration file in /boot. Make sure that the symbolic link
> > of /etc/sysconfig/grub is still pointing to /etc/default/grub file.
> >
> > Cheers, Edouard.
>
> Hi Earl, just following on from what Edouard said, I have never used
> /etc/sysconfig/grub to make grub changes, as until your thread I didn't
> know it existed. All the grub documentation I have seen has said to make
> changed directly to /etc/default/grub, which is what I have always done.
> Like Tom and you have both indicated I have always run
> grub2-mkconfig/grub2-install manually because I don't like the format of
> the grub menu built by grubby (which is automatically run when a new kernel
> is installed as Tom said). Also as I understand it, grubby does not use
> /etc/default/grub to build its grub menus.
>
> From what you have shown in your thread it looks like /etc/sysconfig/grub
> is linked to the wrong file. It seems to be linked to
> /etc/grub.d/00-header, so you may want to re-link it back to
> /etc/default/grub. I have checked on my F24 system and /etc/sysconfig/grub
> is a link to /etc/default/grub.
>
> regards,
> Steve

Thanks for the responses all, I have confirmed that the symbolic link
points to /etc/default/grub

$ ls -la /etc/sysconfig/
total 152
lrwxrwxrwx.   1 root root    17 Jun 11 02:31 grub -> /etc/default/grub

when I use less to read /etc/default/grub, below is what I am seeing;
therefore, the /etc/default/grub file is not the same on this box, I will
whip up a F24 KVM instance and copy the /etc/default/grub file to this box
and I think I should be good.

# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
set pager=1

if [ -s $prefix/grubenv ]; then
  load_env
fi
if [ "${next_entry}" ] ; then
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
else
   set default="${saved_entry}"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else
*/etc/default/grub*

[Earl Ramirez]

Thanks again all,

I copied the /etc/default/grub from the KVM, modified the
GRUB_CMDLINE_LINUX and everything is as expected now.

[Tod Merley]

Well I only glanced at the replies and all - which take an approach which
seems kinda strange - but I am not much into Fedora at this time.

I am suspicious that the approach here may not handle kernel updates well.

Well perhaps a few things I learned during my short quest to make a kind of
“backup-tool repair-tool forensic-tool multi-distro” flash drive may be
useful here.  I made some flash drives which I do use from time to time
today but I got discouraged by the “firmware can equal maleware” issues
with flash drives so planned to move on (likely to USB-SSD if I ever get
back to it).

This was making an normal “hard drive” boot environment for an Ubuntu
install with the modification to the grub control files to produce an
Ubuntu installation on the flash drive which would:

process updates well including changes to the kernel
NOT probe the local environment when processing kernel updates
Preserve the “menuentry boot stanzas” which would boot to the tools above
(loop mounted .iso and other Linux partitions on the flash drive).

The grub control files:

/etc/default/grub

Here adding the “ GRUB_DISABLE_OS_PROBER=true “ line prevented looking at
the local environment while building the flash drives on various boxes.
There are many switches and controls available here.

/etc/grub.d/40_custom   (note: the README in /etc/grub.d)

Here you can add “menuentry boot stanzas” which will automatically make
themselves part of grub.cfg ( /boot/grub/grub.cfg in Ubuntu) during an
update process involving a new kernel.

HTH

On Thu, Jul 7, 2016 at 10:05 PM, Earl A Ramirez 
wrote:
> Thanks again all,
>
> I copied the /etc/default/grub from the KVM, modified the
> GRUB_CMDLINE_LINUX and everything is as expected now.
>
> --
> Kind Regards
> Earl Ramirez
>
> --
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[Tom Horsley]

On Thu, 7 Jul 2016 23:52:18 -0700
Tod Merley wrote:
> I am suspicious that the approach here may not handle kernel updates well.

Kernel updates utterly ignore /etc/default/grub
and just copy the new kernel's args from one of the
old kernel's args.

[Earl Ramirez]

On 8 July 2016 at 18:10, Tom Horsley  wrote:
> On Thu, 7 Jul 2016 23:52:18 -0700
> Tod Merley wrote:
> > I am suspicious that the approach here may not handle kernel updates
>
> well.
>
> Kernel updates utterly ignore /etc/default/grub
> and just copy the new kernel's args from one of the
> old kernel's args.
> --
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> [e-mail]
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> Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
> Have a question? Ask away: http://ask.fedoraproject.org

That is true but when you run grub2-mkconfig -o
/boot/efi/EFI/fedora/grub.cfg it will update all of the kernel arguments;
therefore, when the kernel is updated there will be no issues.

[Tod Merley]

Earl A Ramirez thanks for sharing this issue.

I am interested in how it goes with this over time.

I am interested in which UEFI/Secure boot modes you use and how.

I hope all goes well.

On Fri, Jul 8, 2016 at 4:29 AM, Earl A Ramirez 
wrote:
> On 8 July 2016 at 18:10, Tom Horsley  wrote:
> > On Thu, 7 Jul 2016 23:52:18 -0700
> > Tod Merley wrote:
> > > I am suspicious that the approach here may not handle kernel updates
> >
> > well.
> >
> > Kernel updates utterly ignore /etc/default/grub
> > and just copy the new kernel's args from one of the
> > old kernel's args.
> > --
> > users mailing list
> > [e-mail]
> > To unsubscribe or change subscription options:
> > https://lists.fedoraproject.org/admin/lists/[e-mail]
> > Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
> > Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
> > Have a question? Ask away: http://ask.fedoraproject.org
>
> That is true but when you run grub2-mkconfig -o
> /boot/efi/EFI/fedora/grub.cfg it will update all of the kernel arguments;
> therefore, when the kernel is updated there will be no issues.
>
> --
> Kind Regards
> Earl Ramirez
>
> --
> users mailing list
> [e-mail]
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[Tom Horsley]

On Fri, 8 Jul 2016 13:05:09 +0800
Earl A Ramirez wrote:
> I copied the /etc/default/grub from the KVM, modified the
> GRUB_CMDLINE_LINUX and everything is as expected now.

Maybe I'm paranoid, but one file being utterly
incorrect would lead me to wonder how many other
files were also messed up :-(.