Difference between revisions of "Recover From Grub Failure"
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| − | During to the upgrade from 3.x to 4.x, I found myself without a working grub and unable to boot. | + | During to the upgrade from 3.x to 4.x, I found myself without a working grub and unable to boot. Monitor shows: |
| + | * grub rescue > | ||
| + | |||
I attempted to use the proxmox 4.1 install disk, but found it had a bug where the prompt would not accept input. | I attempted to use the proxmox 4.1 install disk, but found it had a bug where the prompt would not accept input. | ||
| − | You'll need a ISO for a 64 bit version of Ubuntu, | + | You'll need a ISO for a 64 bit version of Ubuntu or Debian Rescue CD, must be 64 bit. |
| − | Boot | + | Boot Ubuntu/Debian off the ISO. We do not want to install Ubuntu/Debian, just run it live off the ISO/DVD. |
First We need to activate LVM and mount the the root partition that is inside the LVM container. | First We need to activate LVM and mount the the root partition that is inside the LVM container. | ||
| Line 11: | Line 13: | ||
Mount all the filesystems that are already there so we can upgrade/install grub. Your paths may vary depending on your drive configuration. | Mount all the filesystems that are already there so we can upgrade/install grub. Your paths may vary depending on your drive configuration. | ||
| − | *sudo mkdir /media/ | + | *sudo mkdir /media/RESCUE |
| − | *sudo mount /dev/pve/root /media/ | + | *sudo mount /dev/pve/root /media/RESCUE/ |
| − | *sudo mount /dev/sda1 /media/ | + | *sudo mount /dev/sda1 /media/RESCUE/boot |
| − | *sudo mount -t proc proc /media/ | + | *sudo mount -t proc proc /media/RESCUE/proc |
| − | *sudo mount -t sysfs sys /media/ | + | *sudo mount -t sysfs sys /media/RESCUE/sys |
| − | *sudo mount -o bind /dev /media/ | + | *sudo mount -o bind /dev /media/RESCUE/dev |
Chroot into your proxmox install. | Chroot into your proxmox install. | ||
| − | *chroot /media/ | + | *chroot /media/RESCUE |
Then upgrade grub and install it. | Then upgrade grub and install it. | ||
Revision as of 12:58, 21 August 2016
During to the upgrade from 3.x to 4.x, I found myself without a working grub and unable to boot. Monitor shows:
- grub rescue >
I attempted to use the proxmox 4.1 install disk, but found it had a bug where the prompt would not accept input.
You'll need a ISO for a 64 bit version of Ubuntu or Debian Rescue CD, must be 64 bit.
Boot Ubuntu/Debian off the ISO. We do not want to install Ubuntu/Debian, just run it live off the ISO/DVD.
First We need to activate LVM and mount the the root partition that is inside the LVM container.
- sudo vgscan
- sudo vgchange -ay
Mount all the filesystems that are already there so we can upgrade/install grub. Your paths may vary depending on your drive configuration.
- sudo mkdir /media/RESCUE
- sudo mount /dev/pve/root /media/RESCUE/
- sudo mount /dev/sda1 /media/RESCUE/boot
- sudo mount -t proc proc /media/RESCUE/proc
- sudo mount -t sysfs sys /media/RESCUE/sys
- sudo mount -o bind /dev /media/RESCUE/dev
Chroot into your proxmox install.
- chroot /media/RESCUE
Then upgrade grub and install it.
- grub-upgrade
- grub-install /dev/sda
If there are no error messages, you should be able to reboot now.
Credit: https://www.nerdoncoffee.com/operating-systems/re-install-grub-on-proxmox/