@marin-n's fix
(https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1889509/comments/16)
worked perfectly for us.
I took some slightly more detailed notes of what I did through the
portal rather than the CLI:
> For Azure users (the same should work in any cloud, with small changes) that
> end up here while looking for this bug, the steps to recover are:
>
> Deploy a recovery VM using AzCli or just attach a copy of the affected OS vm
> disk to a rescue VM.
> Once done, connected to rescue VM and:
>
> $ sudo su -
> # mkdir /rescue
> # mount /dev/sdc1 /rescue
> # for fs in {proc,sys,tmp,dev}; do mount -o bind /$fs /rescue/$fs; done
> # cd /rescue
> # chroot /rescue
> # lsblk <-- this will identify the attached disk, usualy /dev/sdc
> # grub-install /dev/sdc
> # exit
> # cd /
> # for fs in {proc,sys,tmp,dev}; do umount /rescue/$fs; done
> # umount /rescue
>
> Now you should be able to swap back the repaired disk to affected VM.
Ok, step by step:
> Deploy a recovery VM
What sort of VM is that? Attempted creating a regular Ubuntu 18.04 LTS
VM (same as our broken VM)
All normal except for connecting to an existing disk. Looks like you
can't attach to a disk unless you first somehow move it from another
machine (detach it) first.
> attach a copy of the affected OS vm disk to a rescue VM.
To create a copy, you can take a read only snapshot of the disk and then
create a new Managed Disk based on the snapshot.
The only disk you need a snapshot of is the *OS* disk, not the data
disk.
You can create the recovery VM without a data disk, just the OS disk
that automatically gets created.
You can then add the Managed Disk OS snapshot to the recovery VM as a
data disk.
Then you can log into the recovery VM and follow the steps above.
All the steps completed without error - we could copy and paste the
exact messages
Then log out and stop the VM.
You can then go into the broken VM and under the Disks section of the VM
select 'Swap OS Disk'.
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https://bugs.launchpad.net/bugs/1889509
Title:
grub boot error : "symbol 'grub_calloc' not found
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