post_install() {
  getent group hadoop &>/dev/null || groupadd -r hadoop >/dev/null
  getent passwd hadoop &>/dev/null || useradd -r -g hadoop -d /etc/hadoop hadoop >/dev/null

  if [ ! -d /etc/hadoop/.ssh ] ; then
    mkdir -p /etc/hadoop/.ssh
  fi

  chown -R hadoop:hadoop /etc/hadoop

  if [ ! -e /etc/hadoop/.ssh/id_rsa ] ; then
    su -s /bin/bash -c "ssh-keygen -t rsa -N '' -f ~/.ssh/id_rsa" - hadoop
    su -s /bin/bash -c "cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys" - hadoop
  fi

  echo "An SSH key-pair has been created. Depending on your SSHD configuration you may"
  echo "need to connect to localhost as user 'hadoop' to make sure Hadoop can connect."
  echo ""
  echo "$ ssh localhost"

  echo ""
  echo "===> Read https://wiki.archlinux.org/index.php/Hadoop for more information"
  true
}

post_upgrade() {
  true
}

post_remove() {
  getent passwd hadoop &>/dev/null && userdel hadoop >/dev/null
  getent group hadoop &>/dev/null && groupdel hadoop >/dev/null
  true
}