Create a LVM volume in a Vagrant-driven VirtualBox using 75% of the space in the VG

Vagrantfile

# -*- mode: ruby -*-
# vi: set ft=ruby :

# This is a Vagrant setup that sets up a logical volume mounted at /var/lib/mysql
# using only 75% of the avilable space in the volume group it lives in. 
# DEPENCIES: vagrant-persistent-storage plugin.

Vagrant.configure(2) do |config|
  config.vm.box = "opscode-ubuntu-14.04"

  # Use the vagrant-persistent-storage plugin to make a disk
  config.persistent_storage.enabled = true
  config.persistent_storage.location = "disks/sourcehdd.vdi"
  config.persistent_storage.size = 500
  config.persistent_storage.mount = false
  config.persistent_storage.use_lvm = true
  config.persistent_storage.format = false
  config.persistent_storage.volgroupname = 'vg1'

  # Okay, the above creates vg 'vg1' with LV 'vps' and formats it as ext3, using
  # the entire volume group.
  # We'll need to undo some of that. Nuke that LV, make a new LV using 75% of
  # the available space, format as ext4, and mont it at /var/lib/mysql.
  $disk_cleanup = <<SCRIPT
if lvs | grep vps; then
  echo "==> SHELL PROVISIONER: Setting up logical volumes"
  lvremove -f vg1
  lvcreate vg1 -n mysql -l 75%FREE
  mkfs.ext4 /dev/vg1/mysql
  mkdir -p /var/lib/mysql
  echo "/dev/mapper/vg1-mysql /var/lib/mysql               ext4    errors=remount-ro 0       1" >> /etc/fstab
  mount -a
fi
SCRIPT
  config.vm.provision "shell", inline: $disk_cleanup

end