F28 server boots to the grub prompt even after dnf update and grub2-mkconfig

[linux guy]

I have an up to date F28 server that boots to the grub prompt.   This
started after a failed dnf update.

The computer will boot to an emergency mode command prompt if I set it up
properly from the grub prompt.

grub> set root=(lvm/fedora-root)
grub> linuxefi (hd0,gpt2)/vmlinuz-0-rescue... root=/dev/mapper/fedora-root
grub>initrdefi (hd0,gpt2)/initramfs-0-rescue....img
grub>boot

I can get networking working
#ls /sys/call/net   <- find Ethernet device is enp3s0
# ifup enp3s0
# ping www.google.com

Now update it
# dnf update

Regenerate the grub2 config file
# grub2-mkconfig

Reboot
# shutdown -r now

It still boots to the grub prompt.
Why does it boot to the grub prompt and what do I need to do to fix it ?

[stan]

On Tue, 30 Oct 2018 11:28:36 -0600
linux guy <linuxguy123(a)gmail.com&gt; wrote:

>  I have an up to date F28 server that boots to the grub prompt.  
> This
>  started after a failed dnf update.
>  
>  The computer will boot to an emergency mode command prompt if I set
>  it up properly from the grub prompt.
>  
>  grub> set root=(lvm/fedora-root)
>  grub> linuxefi (hd0,gpt2)/vmlinuz-0-rescue...
>  grub> root=/dev/mapper/fedora-root
>  grub>initrdefi (hd0,gpt2)/initramfs-0-rescue....img
>  grub>boot  
>  
>  I can get networking working
>  #ls /sys/call/net   <- find Ethernet device is enp3s0
>  # ifup enp3s0
>  # ping www.google.com
>  
>  Now update it
>  # dnf update 
Does dnf give any errors because of the interrupted update?

>  
>  Regenerate the grub2 config file
>  # grub2-mkconfig
>  
>  Reboot
>  # shutdown -r now
>  
>  It still boots to the grub prompt.
>  Why does it boot to the grub prompt and what do I need to do to fix
>  it ? 
Two things you should try.

1.  If not already, remove rhgb and quiet from the kernel boot line so
you can see the boot messages, and the final error that is throwing you
into the grub prompt.

2.  After getting the system up and before you reboot, look in the
journal to see what is reported about the issue causing the drop to a
grub prompt.
journalctl -b
will show the last boot.

That you have to set the root manually suggests to me that the boot
record isn't pointing to the right place.  Correcting this is different
for uefi and mbr, so you'll have to tell us which method you are
using.  I don't see how this could happen from an interrupted dnf
update unless the disk was somehow corrupted, but it is what it is.
Maybe you should try running a non destructive file system check to see
that the file system is intact.

If you have a rescue cd or usb, it is a lot easier to boot it and do
these kinds of things from a separate fully functioning system.

[linux guy]

I'm using UEFI.

On Tue, Oct 30, 2018 at 2:43 PM stan <stanl-fedorauser(a)vfemail.net&gt; wrote:

>  On Tue, 30 Oct 2018 11:28:36 -0600
>  linux guy <linuxguy123(a)gmail.com&gt; wrote:
>
>  > I have an up to date F28 server that boots to the grub prompt.   This
>  > started after a failed dnf update.
>  >
>  > The computer will boot to an emergency mode command prompt if I set
>  > it up properly from the grub prompt.
>  >
>  > grub> set root=(lvm/fedora-root)
>  > grub> linuxefi (hd0,gpt2)/vmlinuz-0-rescue...
>  > grub> root=/dev/mapper/fedora-root
>  > grub>initrdefi (hd0,gpt2)/initramfs-0-rescue....img
>  > grub>boot
>  >
>  > I can get networking working
>  > #ls /sys/call/net   <- find Ethernet device is enp3s0
>  > # ifup enp3s0
>  > # ping www.google.com
>  >
>  > Now update it
>  > # dnf update
>
>  Does dnf give any errors because of the interrupted update?
>
>  >
>  > Regenerate the grub2 config file
>  > # grub2-mkconfig
>  >
>  > Reboot
>  > # shutdown -r now
>  >
>  > It still boots to the grub prompt.
>  > Why does it boot to the grub prompt and what do I need to do to fix
>  > it ?
>
>  Two things you should try.
>
>  1.  If not already, remove rhgb and quiet from the kernel boot line so
>  you can see the boot messages, and the final error that is throwing you
>  into the grub prompt.
>
>  2.  After getting the system up and before you reboot, look in the
>  journal to see what is reported about the issue causing the drop to a
>  grub prompt.
>  journalctl -b
>  will show the last boot.
>
>  That you have to set the root manually suggests to me that the boot
>  record isn't pointing to the right place.  Correcting this is different
>  for uefi and mbr, so you'll have to tell us which method you are
>  using.  I don't see how this could happen from an interrupted dnf
>  update unless the disk was somehow corrupted, but it is what it is.
>  Maybe you should try running a non destructive file system check to see
>  that the file system is intact.
>
>  If you have a rescue cd or usb, it is a lot easier to boot it and do
>  these kinds of things from a separate fully functioning system.
>  _______________________________________________
>  users mailing list -- users(a)lists.fedoraproject.org
>  To unsubscribe send an email to users-leave(a)lists.fedoraproject.org
>  Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html
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>

[Tom H]

On Tue, Oct 30, 2018 at 7:23 PM linux guy <linuxguy123(a)gmail.com&gt; wrote:
>  I have an up to date F28 server that boots to the grub prompt.   This started after a
> failed dnf update.
>
>  The computer will boot to an emergency mode command prompt if I set it up properly from
> the grub prompt.
>
>  grub> set root=(lvm/fedora-root)
>  grub> linuxefi (hd0,gpt2)/vmlinuz-0-rescue... root=/dev/mapper/fedora-root
>  grub>initrdefi (hd0,gpt2)/initramfs-0-rescue....img
>  grub>boot
>
>  I can get networking working
>  #ls /sys/call/net   <- find Ethernet device is enp3s0
>  # ifup enp3s0
>  # ping www.google.com
>
>  Now update it
>  # dnf update
>
>  Regenerate the grub2 config file
>  # grub2-mkconfig 
Are you running this exact command? Or are you running "grub2-mkconfig
-o /boot/grub2/grub.cfg"?


> Reboot
> # shutdown -r now
>
> It still boots to the grub prompt.
> Why does it boot to the grub prompt and what do I need to do to fix it ?

[linux guy]

I was running grub2-mkconfig.  I did not use -o.

I never even thought of that.   I was running it from the wrong directory
!  Good catch.  Thanks for replying.

[linux guy]

It still boots to the grub prompt, even when I use -o /boot/grub2/grub.cfg


On Thu, Nov 1, 2018 at 1:33 PM linux guy <linuxguy123(a)gmail.com&gt; wrote:

>  I was running grub2-mkconfig.  I did not use -o.
>
>  I never even thought of that.   I was running it from the wrong directory
>  !  Good catch.  Thanks for replying.
>
>

[Samuel Sieb]

On 11/26/18 7:56 PM, linux guy wrote:
>  It still boots to the grub prompt, even when I use -o
> /boot/grub2/grub.cfg 
That is still the wrong file.  You need either
/boot/efi/EFI/fedora/grub.cfg
or
/etc/grub2-efi.cfg which is a symlink to the first one.

[linux guy]

Thank you.

On Mon, Nov 26, 2018 at 11:12 PM Samuel Sieb <samuel(a)sieb.net&gt; wrote:

>  On 11/26/18 7:56 PM, linux guy wrote:
>  > It still boots to the grub prompt, even when I use -o
>  /boot/grub2/grub.cfg
>
>  That is still the wrong file.  You need either
>  /boot/efi/EFI/fedora/grub.cfg
>  or
>  /etc/grub2-efi.cfg which is a symlink to the first one.
>  _______________________________________________
>  users mailing list -- users(a)lists.fedoraproject.org
>  To unsubscribe send an email to users-leave(a)lists.fedoraproject.org
>  Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html
>  List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
>  List Archives:
>  https://lists.fedoraproject.org/archives/list/[e-mail]
>

[linux guy]

Interesting.  /boot/efi/EFI/fedora/grub.cfg didn't exist on my
workstation.  But /etc/grub2-efi.cfg points to it !   /boot/efi existed,
but it was empty.

I created /boot/efi/EFI/fedora/.
I ran grub2-mkconfig -o/boot/grub2/grub.cfg  It ran without error.
I rebooted using shutdown -r now
It rebooted to the grub prompt.

Now what ?



On Mon, Nov 26, 2018 at 11:12 PM Samuel Sieb <samuel(a)sieb.net&gt; wrote:

>  On 11/26/18 7:56 PM, linux guy wrote:
>  > It still boots to the grub prompt, even when I use -o
>  /boot/grub2/grub.cfg
>
>  That is still the wrong file.  You need either
>  /boot/efi/EFI/fedora/grub.cfg
>  or
>  /etc/grub2-efi.cfg which is a symlink to the first one.
>  _______________________________________________
>  users mailing list -- users(a)lists.fedoraproject.org
>  To unsubscribe send an email to users-leave(a)lists.fedoraproject.org
>  Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html
>  List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
>  List Archives:
>  https://lists.fedoraproject.org/archives/list/[e-mail]
>

[Samuel Sieb]

On 11/27/18 3:17 PM, linux guy wrote:
>  Interesting.  /boot/efi/EFI/fedora/grub.cfg didn't exist on my 
>  workstation.  But /etc/grub2-efi.cfg points to it !   /boot/efi existed, 
>  but it was empty. 
How are you booting into it right now to do this?

Btw, both grub.cfg symlinks are always created whether it's an EFI 
install or not.

[Berend De Schouwer]

On Tue, 2018-11-27 at 16:17 -0700, linux guy wrote:
>  Interesting.  /boot/efi/EFI/fedora/grub.cfg didn't exist on my
>  workstation.  But /etc/grub2-efi.cfg points to it !   /boot/efi
>  existed, but it was empty.   
This means that either /boot/efi/ isn't mounted after you reboot (check
/etc/fstab) or your system isn't using EFI, but is using BIOS/MBR boot.

EFI needs /boot/efi/, and it needs to be FAT, not ext4 or xfs, so if
your system boots using EFI, there's a (usually +- 200MB) FAT partition
somewhere on a disk, with some data.

BIOS/MBR doesn't needs that.  Some EFI can boot in a legacy mode.


If you manually create /boot/efi/EFI/fedora/grub.cfg you likely created
a file on /boot, which is likely ext4, which the EFI bios won't load. 
Look for a FAT partition and mount that under /boot/efi/.  *Then* look
at grub.cfg.

(there need to be a few other files in /boot/efi/ too)