Why we do not store virtual machines on the server?

https://help.ubuntu.com/community/VirtualBox

Connect to /playpen
  Note size -- how many virtual machines can this contain
  Note protection
  Look at playpen/ISO -- protection
  Look at /playpen/VM -- protection  (any files there???)
  copy /csciloc/ubuntu/Distributions/ubuntu-16.04.1-desktop-amd64.iso
    to /playpen/ISO

Start virtualbox
  Place your virtual disk image in /playpen/VM
    And use fixed 16 Gbytes
      That's more than the default
      Be leaves space for others
    Otherwise use defaults
  Don't download updates on the install
    Wait until the reboot

Reboot
  apt-get update
  apt-get upgrade
  apt-get dist-upgrade

Check out networking (NAT)

Create a user