Ubuntu Reduce installation size

# just in case we are retrying and apt is in a bad state
dpkg --configure -a

# DEBIAN_FRONTEND=noninteractive is useful for scripting.
# prevents getting prompts that will hang our script.

# ubuntu-minimal is a meta package that depends on the packages
# in ubuntu-minimal install.
# Need aptitude to autoremove everything we don't depend on.
DEBIAN_FRONTEND=noninteractive \
  apt-get --assume-yes install aptitude ubuntu-minimal

# mark all packages as automatically installed except
# ubuntu-minimal, kernel, systemd and openssh.
# For some reason systemd isn't part of ubuntu-minimal.
# Any dependencies of these four packages will be kept.
# All others that aren't dependencies will be removed since
# we have told apt they are automatically installed
# (ie we don't care about them unless we need them as a dep)
DEBIAN_FRONTEND=noninteractive \
  aptitude --assume-yes markauto \
    '~i!?name(ubuntu-minimal~|linux-generic~|systemd~|openssh-server|grub~|lvm2~)'

# purge all removed packages that were not purged.
# removes leftover config/cruft.
DEBIAN_FRONTEND=noninteractive \
  aptitude --assume-yes purge '~c'