[PLUG] Fixing /boot/ too small

[JP Vossen via plug <plug@lists.phillylinux.org>]

Summary: I need to fix some Mint-19 workstations where /boot/ is too small.

Solution: below but needs sanity check.

Details:

I have some workstations I installed a long time ago and /boot/ is now 
too small.  200M was fine when I built them, but not anymore.  I did a 
hacked RAID-1 mdadm install because whatever installer (Ubuntu or Mint) 
didn't do RAID, but I didn't do LVM.  I've never had to re-install 
because...RAID-1!  I've replaced all the disks over the years by 
swapping over to bigger ones, re-mirroring, and growing /.

The too small /boot/ is now causing a lot of problems because every time 
I run OS updates that want `update-initramfs` it fails due to lack of 
space, which fails the update, which fails the Ansible task.  And then I 
am sad.

Fix: All the disk space is allocated, and they are not using LVM anyway, 
so I can't just make /boot/ bigger.  (Well, if I was swapping to bigger 
disks I probably could, but that's not soon enough.)  But I *CAN* just 
move /boot/ from its own md device and partition into '/' where it 
probably should have been in the first place.  I'd then be wasting the 
old /boot/ space, but I can live with that or find something else to put 
in there.  Maybe make it /tmp/.

I've done the following process on a sacrificial Mint-19 VM and rebooted 
and it Just Worked.  BUT that VM was not running mdadm because I didn't 
feel like hacking the install again.  I've also done the *process* on 2 
of the workstations, but not *rebooted* yet.  One node is 1.5 hours away 
in NJ...

On one hand, this is a very simple and straightforward process, even 
with mdadm in the mix.  OTOH, GRUB and the boot process are subtle and 
quick to anger.

Solution:

sudo -s
cp -a /boot /boot.new
mkdir /boot.old
touch /boot.new/z-boot.new /boot.old/z-boot.old /boot/z-boot.orig
	# So I know what used to be where
vi /etc/fstab
	# To change the mount for /boot/ to /boot.old/
umount /boot
rmdir /boot
mv /boot.new /boot
update-initramfs -u -k all
update-grub
### reboot?!?

Sanity check or clues for anything that might bite me?

Thanks,
JP
--  -------------------------------------------------------------------
JP Vossen, CISSP | http://www.jpsdomain.org/ | http://bashcookbook.com/
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