class ntp::timezone(
  $zone = lookup('ntp::zone', undef, undef, '')
) {

  case $zone {
    '': { fail("you need to define ntp::zone for ntp module") }
  }

  # the needed packages
  package { "tzdata": ensure => installed, }

  # adjust localtime
  file { "/etc/localtime":
    ensure  => "/usr/share/zoneinfo/${zone}",
    require => Package["tzdata"],
  }
}