gistfile1.txt

describe 'hosts_file' do
	let(:params) do {
		:hosts_fqdn_aliases => ['test1.example.com','test1'],
		'hosts_resources' => {
		    'extra' => {
		      'name'         => 'extra.example.com',
			  'host_aliases' => ['extra', 'blah', 'blah.examplecar.com', 'blah.example.com'],
			  'ip'           => '10.10.10.11',
	        }
	    },
	}
	end
	let(:facts) do {
		:operatingsystem           => 'RedHat',
		:operatingsystemmajrelease => '6',
		:fqdn                      => 'test.example.com',
		:hostname                  => 'test',
		:ipaddress_eth0            => '10.10.10.10',
	}
	end
	it 'should have an augeas resource' do
		should contain_augeas('rename_ip6')
	end
	describe_augeas 'renameip6', :lens => 'hosts', :target => 'etc/hosts' do
		it 'should change canonical' do
			should execute.with_change
			aug_get('canonical').should == 'localhost6'
			should execute.idempotently
		end
	end
	it do
		should contain_host('localhost').with({
			'ensure'       => 'present',
			'host_aliases' => ['localhost.localdomain', 'localhost4', 'localhost4.localdomain4'],
			'ip'           => '127.0.0.1',
		})
		should contain_host('localhost6').with({
			'ensure'       => 'present',
			'host_aliases' => ['localhost.localdomain', 'localhost', 'localhost6.localdomain6'],
			'ip'           => '::1',
		})
		should contain_host('fqdn').with({
			'name'         => 'test.example.com',
			'ensure'       => 'present',
			'host_aliases' => ['test', 'test1', 'test1.example.com'],
			'ip'           => '10.10.10.10',
		})
		should contain_host('extra').with({
			'name'         => 'extra.example.com',
			'ensure'       => 'present',
			'host_aliases' => ['extra', 'blah', 'blah.examplecar.com', 'blah.example.com'],
			'ip'           => '10.10.10.11',
		})
	end
end

init.pp

class hosts_file (
  $hosts_resources    = $hosts_file::params::hosts_resources,
  $hosts_osVerArch    = $hosts_file::params::hosts_osVerArch,
  $hosts_fqdn_aliases = $hosts_file::params::hosts_fqdn_aliases,
  $hosts_defaults     = $hosts_file::params::hosts_defaults,
  $hosts_aug_defaults = $hosts_file::params::hosts_aug_defaults,
  $defaults           = $hosts_file::params::defaults,
) inherits hosts_file::params
{
  contain hosts_file::config
}

params.pp

class hosts_file::params {
  $hosts_resources    = false
  $hosts_osVerArch    = "${::operatingsystem} ${::operatingsystemmajrelease}"
  $hosts_fqdn_aliases = []
  $defaults           = {
    ensure  => 'present',
    require => Augeas['rename_ip6'],
  }
  case $hosts_osVerArch {
    'RedHat 6': {
      $hosts_defaults = {
        localhost      => {
          host_aliases => [ 'localhost.localdomain', 'localhost4', 'localhost4.localdomain4' ],
          ip           => '127.0.0.1',
        },
        localhost6     => {
          host_aliases => [ 'localhost.localdomain', 'localhost', 'localhost6.localdomain6' ],
          ip           => '::1',
        },
        fqdn           => {
          name         => $::fqdn,
          host_aliases => concat([$::hostname],$hosts_fqdn_aliases),
          ip           => $::ipaddress_eth0,
        },
      }
      $hosts_aug_defaults = {
        rename_ip6 => {
          context  => '/files/etc/hosts',
          changes  => [
            "set *[ipaddr = '::1']/canonical localhost6",
            "set *[ipaddr = '::1']/alias[1] localhost.localdomain",
            "set *[ipaddr = '::1']/alias[2] localhost",
            "set *[ipaddr = '::1']/alias[3] localhost6.localdomain6",
          ],
        }
      }
    }
    default: {
      fail("Module ${module_name} does not support the ${hosts_osVerArch} Operating System")
    }
  }
}

Change the hosts_file::params class to have an actual param. Then you could set hosts_file::params::hosts_fqdn_aliases via hiera to the correct value and all the classes in hosts_file would receive the correct value for hosts_file::params::hosts_default.

class hosts_file::params (
  $hosts_fqdn_aliases = [],
) {
  $hosts_resources    = false
  $hosts_osVerArch    = "${::operatingsystem} ${::operatingsystemmajrelease}"
 $defaults           = {
    ensure  => 'present',
    require => Augeas['rename_ip6'],
  }
  case $hosts_osVerArch {
    'RedHat 6': {
      $hosts_defaults = {
        localhost      => {
          host_aliases => [ 'localhost.localdomain', 'localhost4', 'localhost4.localdomain4' ],
          ip           => '127.0.0.1',
        },
        localhost6     => {
          host_aliases => [ 'localhost.localdomain', 'localhost', 'localhost6.localdomain6' ],
          ip           => '::1',
        },
        fqdn           => {
          name         => $::fqdn,
          host_aliases => concat([$::hostname],$hosts_fqdn_aliases),
          ip           => $::ipaddress_eth0,
        },
      }
      $hosts_aug_defaults = {
        rename_ip6 => {
          context  => '/files/etc/hosts',
          changes  => [
            "set *[ipaddr = '::1']/canonical localhost6",
            "set *[ipaddr = '::1']/alias[1] localhost.localdomain",
            "set *[ipaddr = '::1']/alias[2] localhost",
            "set *[ipaddr = '::1']/alias[3] localhost6.localdomain6",
          ],
        }
      }
    }
    default: {
      fail("Module ${module_name} does not support the ${hosts_osVerArch} Operating System")
    }
  }
}