diff --git a/manifests/sentinel.pp b/manifests/sentinel.pp
index ad78b33..65af376 100644
--- a/manifests/sentinel.pp
+++ b/manifests/sentinel.pp
@@ -1,189 +1,189 @@
 # @summary Install redis-sentinel
 #
 # @param auth_pass
 #   The password to use to authenticate with the master and slaves.
 #
 # @param config_file
 #   The location and name of the sentinel config file.
 #
 # @param config_file_orig
 #   The location and name of a config file that provides the source
 #   of the sentinel config file. Two different files are needed
 #   because sentinel itself writes to its own config file and we do
 #   not want override that when puppet is run unless there are
 #   changes from the manifests.
 #
 # @param config_file_mode
 #   Permissions of config file.
 #
 # @param conf_template
 #   Define which template to use.
 #
 # @param daemonize
 #   Have Redis sentinel run as a daemon.
 #
 # @param down_after
 #   Number of milliseconds the master (or any attached slave or sentinel)
 #   should be unreachable (as in, not acceptable reply to PING, continuously,
 #   for the specified period) in order to consider it in S_DOWN state.
 #
 # @param failover_timeout
 #   Specify the failover timeout in milliseconds.
 #
 # @param init_script
 #   Specifiy the init script that will be created for sentinel.
 #
 # @param log_file
 #   Specify where to write log entries.
 #
 # @param log_level
 #   Specify how much we should log.
 #
 # @param master_name
 #   Specify the name of the master redis server.
 #   The valid charset is A-z 0-9 and the three characters ".-_".
 #
 # @param redis_host
 #   Specify the bound host of the master redis server.
 #
 # @param redis_port
 #   Specify the port of the master redis server.
 #
 # @param package_name
 #   The name of the package that installs sentinel.
 #
 # @param package_ensure
 #   Do we ensure this package.
 #
 # @param parallel_sync
 #   How many slaves can be reconfigured at the same time to use a
 #   new master after a failover.
 #
 # @param pid_file
 #   If sentinel is daemonized it will write its pid at this location.
 #
 # @param quorum
 #   Number of sentinels that must agree that a master is down to
 #   signal sdown state.
 #
 # @param sentinel_bind
 #   Allow optional sentinel server ip binding.  Can help overcome
 #   issues arising from protect-mode added Redis 3.2
 #
 # @param sentinel_port
 #   The port of sentinel server.
 #
 # @param service_group
 #   The group of the config file.
 #
 # @param service_name
 #   The name of the service (for puppet to manage).
 #
 # @param service_user
 #   The owner of the config file.
 #
 # @param service_enable
 #   Enable the service at boot time.
 #
 # @param working_dir
 #   The directory into which sentinel will change to avoid mount
 #   conflicts.
 #
 # @param notification_script
 #   Path to the notification script
 #
 # @param client_reconfig_script
 #   Path to the client-reconfig script
 #
 # @example Basic inclusion
 #   include redis::sentinel
 #
 # @example Configuring options
 #   class {'redis::sentinel':
 #     down_after => 80000,
 #     log_file   => '/var/log/redis/sentinel.log',
 #   }
 #
 class redis::sentinel (
   Optional[String[1]] $auth_pass = undef,
   Stdlib::Absolutepath $config_file = $redis::params::sentinel_config_file,
   Stdlib::Absolutepath $config_file_orig = $redis::params::sentinel_config_file_orig,
   Stdlib::Filemode $config_file_mode = '0644',
   String[1] $conf_template = 'redis/redis-sentinel.conf.erb',
   Boolean $daemonize = $redis::params::sentinel_daemonize,
   Integer[1] $down_after = 30000,
   Integer[1] $failover_timeout = 180000,
   Optional[Stdlib::Absolutepath] $init_script = $redis::params::sentinel_init_script,
   String[1] $init_template = 'redis/redis-sentinel.init.erb',
   Redis::LogLevel $log_level = 'notice',
   Stdlib::Absolutepath $log_file = $redis::params::sentinel_log_file,
   String[1] $master_name  = 'mymaster',
   Stdlib::Host $redis_host = '127.0.0.1',
   Stdlib::Port $redis_port = 6379,
   String[1] $package_name = $redis::params::sentinel_package_name,
   String[1] $package_ensure = 'present',
   Integer[0] $parallel_sync = 1,
   Stdlib::Absolutepath $pid_file = $redis::params::sentinel_pid_file,
   Integer[1] $quorum = 2,
   Variant[Undef, Stdlib::IP::Address, Array[Stdlib::IP::Address]] $sentinel_bind = undef,
   Stdlib::Port $sentinel_port = 26379,
   String[1] $service_group = 'redis',
   String[1] $service_name = $redis::params::sentinel_service_name,
   Stdlib::Ensure::Service $service_ensure = 'running',
   Boolean $service_enable = true,
   String[1] $service_user = 'redis',
   Stdlib::Absolutepath $working_dir = $redis::params::sentinel_working_dir,
   Optional[Stdlib::Absolutepath] $notification_script = undef,
   Optional[Stdlib::Absolutepath] $client_reconfig_script = undef,
 ) inherits redis::params {
   require 'redis'
 
   if $facts['os']['family'] == 'Debian' {
     package { $package_name:
       ensure => $package_ensure,
       before => File[$config_file_orig],
     }
 
     if $init_script {
       Package[$package_name] -> File[$init_script]
     }
   }
 
-  $sentinel_bind_arr = [$sentinel_bind].flatten
+  $sentinel_bind_arr = delete_undef_values([$sentinel_bind]).flatten
 
   file { $config_file_orig:
     ensure  => file,
     owner   => $service_user,
     group   => $service_group,
     mode    => $config_file_mode,
     content => template($conf_template),
   }
 
   exec { "cp -p ${config_file_orig} ${config_file}":
     path        => '/usr/bin:/bin',
     subscribe   => File[$config_file_orig],
     notify      => Service[$service_name],
     refreshonly => true,
   }
 
   if $init_script {
     file { $init_script:
       ensure  => file,
       owner   => 'root',
       group   => 'root',
       mode    => '0755',
       content => template($init_template),
     }
 
     exec { '/usr/sbin/update-rc.d redis-sentinel defaults':
       subscribe   => File[$init_script],
       refreshonly => true,
       notify      => Service[$service_name],
     }
   }
 
   service { $service_name:
     ensure => $service_ensure,
     enable => $service_enable,
   }
 }