set root_helper defaults

Starting is essex 2, a new utility has been created
that simplifies the management of sudoers config
for nova since nova runs as a non-root user but
often needs escalated privelages.

http://wiki.openstack.org/Packager/Rootwrap

The default setting for root_helper is sudo which
relies on a complex set of sudoers rules.

These rules can be greatly simplified by setting
root_helper to sudo nova-rootwrap.

This may be problematic b/c it depends on rather
or not this file has been packaged..

This config default has been added to the params
class b/c it depends on what OS packages are used
for installation.

Perhaps I can revisit this once the openstack
packaging matures.

manifests/init.pp

@@ -23,11 +23,9 @@ class nova(
   $verbose = false,
   $nodaemon = false,
   $periodic_interval = '60',
-  $report_interval = '10'
-
-) {
-
-  include nova::params
+  $report_interval = '10',
+  $root_helper = $::nova::params::root_helper
+) inherits nova::params {
 
   Nova_config<| |> {
     require +> Package[$::nova::params::package_names],
@@ -120,6 +118,7 @@ class nova(
     # as well as controller.
     'network_manager': value => $network_manager;
     'use_deprecated_auth': value => true;
+    'root_helper': value => $root_helper;
   }
 
   exec { 'post-nova_config':

manifests/params.pp

@@ -14,6 +14,8 @@ class nova::params {
       $libvirt_package_name     = 'libvirt'
       $libvirt_service_name     = 'libvirtd'
       $special_service_provider = 'init'
+      # redhat specific config defaults
+      $root_helper              = 'sudo nova-rootwrap'
     }
     'Debian': {
       $package_names = ['nova-common',
@@ -33,6 +35,8 @@ class nova::params {
       $libvirt_service_name     = 'libvirt-bin'
       # some of the services need to be started form the special upstart provider
       $special_service_provider = 'upstart'
+      # debian specific nova config
+      $root_helper              = 'sudo'
     }
     default: {
       fail("Unsupported osfamily: ${::osfamily} operatingsystem: ${::operatingsystem}, module ${module_name} only support osfamily RedHat and Debian")