resize-qcow2-disk.sh

sudo virsh domblklist $MACHINE
# copy the file path to the qcow2 disk that you want to resize
sudo qemu-img resize $QCOW2_PATH +20G  # this will add 20G to the disk
sudo virsh start $MACHINE
# ssh into $MACHINE
lsblk  # make sure the disk size is the one you want
sudo apt -y install cloud-guest-utils
sudo growpart /dev/vda 1  # change vda is the disk, and '1' is for the partition number as listed by lsblk.
sudo resize2fs /dev/vda1  # resize the filesystem.
df -h | grep /dev/vda  # validate the new size is active.