You want to make the LSB facts available to facter and puppet
class lsb_facts {
# on Debian
package { 'lsb-release': ensure => 'installed' }
# on Redhat / Fedora
package { 'redhat-lsb': ensure => 'installed' }
}
Before the LSB facts can be used the package that provides the commands they wrap must be installed. While this is simple to do it's not part of the base install of many Linux distributions and so should be done via Puppet.