Increase VM storage on-line

Increase from 300 G to 400 G using the same storage, but leverage LVM on GPT inside the VM.

Host:

376 lvextend -L +100G /dev/mapper/guests--lolguest
377 virsh qemu-monitor-command lolguest info block
378 virsh qemu-monitor-command lolguest info block --hmp
379 virsh qemu-monitor-command lolguest block_resize drive-virtio-disk0 300G --hmp

VM:

480 sgdisk -e /dev/vda # <-- create partition 5
481 gdisk /dev/vda
485 partprobe
487 pvcreate /dev/vda5
488 vgextend ubuntu-vg /dev/vda5
489 lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
490 resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv

Always watch out for paths, partition numbers and names!