DLPX-72158 create script to more easily update grub configuration

[prakashsurya]

Problem

Updating the bootloader on an appliance requires a series of commands to be run, which is easy to forget.

Solution

Add a script to the appliance to make it easy to update the bootloader as needed, with a single command.

Testing

• System Configuration

$ zpool list
NAME        SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
domain0     148G   279M   148G        -         -     4%     0%  1.00x    ONLINE  -
old_rpool  69.5G  21.6G  47.9G        -         -      -    31%  1.00x    ONLINE  /old_rpool
rpool      69.5G  23.1G  46.4G        -         -      -    33%  1.00x    ONLINE  -
$ zfs list -r old_rpool/ROOT
NAME                                  USED  AVAIL  REFER  MOUNTPOINT
old_rpool/ROOT                       15.1G  45.8G    64K  none
old_rpool/ROOT/delphix.d427tUL       15.1G  45.8G    64K  none
old_rpool/ROOT/delphix.d427tUL/data   568M  45.8G   567M  legacy
old_rpool/ROOT/delphix.d427tUL/home    57K  45.8G    57K  legacy
old_rpool/ROOT/delphix.d427tUL/log   60.4M  45.8G  56.0M  legacy
old_rpool/ROOT/delphix.d427tUL/root  14.5G  45.8G  9.58G  /old_rpool

• Recover

$ sudo ./update-appliance-bootloader recover old_rpool delphix.d427tUL
Installing for i386-pc platform.
Installation finished. No error reported.
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Sourcing file `/etc/default/grub.d/kdump-tools.cfg'
Sourcing file `/etc/default/grub.d/override.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.15.0-1048-dx2023112215-3a78f9e6a-oracle
Found initrd image: /boot/initrd.img-5.15.0-1048-dx2023112215-3a78f9e6a-oracle
Found linux image: /boot/vmlinuz-5.15.0-1041-dx2023090706-5083803f2-oracle
Found initrd image: /boot/initrd.img-5.15.0-1041-dx2023090706-5083803f2-oracle
done

• Update

$ sudo ./update-appliance-bootloader update
Installing for i386-pc platform.
Installation finished. No error reported.
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Sourcing file `/etc/default/grub.d/kdump-tools.cfg'
Sourcing file `/etc/default/grub.d/override.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.15.0-1048-dx2023112215-3a78f9e6a-oracle
Found initrd image: /boot/initrd.img-5.15.0-1048-dx2023112215-3a78f9e6a-oracle
Found linux image: /boot/vmlinuz-5.15.0-1041-dx2023090706-5083803f2-oracle
Found initrd image: /boot/initrd.img-5.15.0-1041-dx2023090706-5083803f2-oracle
done

[sumedhbala-delphix]

Add debugging to the install step?

[grwilson]

Should this be used by the upgrade scripts?

[prakashsurya]

Should this be used by the upgrade scripts?

possibly.. I think we definitely could.. as is, this script doesn't support not-in-place upgrades, but that could likely be added (or removed, since we never do not-in-place upgrades)..

the problem, though, is the script only exists for "new" versions (after we land it), so in order to eliminate the duplicated code between here, and upgrade, we'd need to wait for the "min version" to be a version containing this script..

I'm not opposed to having some version conditional.. e.g. "if running version with script; use script; otherwise run commands".. or just waiting till "min version" is adequate, and then always use the script..

regardless, that work would be in appliance-build's repository/scripts, and we'd need to land this change first..

if you feel strongly, I can land this change, and then look into the changes needed to consume it via upgrade..