No limitation on the number of item at this level. It has already been checked when preparing the query parameters
#!/bin/bash
# File Managed by Puppet
export PATH=$PATH:/bin:/sbin:/usr/bin:usr/sbin
<% if scope.lookupvar('::operatingsystem') == 'Debian' or scope.lookupvar('::operatingsystem') == 'Ubuntu' -%>
apt-get update ; apt-get install -y <%= @packages %>
<% elsif scope.lookupvar('::operatingsystem') == 'Centos' or scope.lookupvar('::operatingsystem') == 'RedHat' -%>
yum install -y <%= @packages %>
<% end -%>