Deprecate support for linuxbridge mechanism driver

... and disables it by default. The neutron team decided to make it
experimental[1] and now the plugin is not loaded unless the user
explicitly enables the experimental flag.

[1] https://review.opendev.org/845181

Change-Id: If1ea40d783ac852865f6de00ddb2a1da090ca846

manifests/agents/ml2/linuxbridge.pp

@@ -1,5 +1,6 @@
 # == Class: neutron::agents::ml2::linuxbridge
 #
+# DEPRECATED !!
 # Setups Linuxbridge Neutron agent for ML2 plugin.
 #
 # === Parameters
@@ -96,6 +97,8 @@ class neutron::agents::ml2::linuxbridge (
   include neutron::deps
   include neutron::params
 
+  warning('Support for the linuxbridge mechanism driver has been deprecated.')
+
   resources { 'neutron_agent_linuxbridge':
     purge => $purge_config,
   }

manifests/config.pp

@@ -33,9 +33,6 @@
 # [*sriov_agent_config*]
 #   (optional) Manage configuration of sriov_agent.ini
 #
-# [*linuxbridge_agent_config*]
-#   (optional) Manage configuration of linuxbridge_agent.ini
-#
 # [*macvtap_agent_config*]
 #   (optional) Manage configuration of macvtap_agent.ini
 #
@@ -95,6 +92,9 @@
 # [*plugin_nsx_config*]
 #   (optional) Manage configuration of plugins/vmware/nsx.ini
 #
+# [*linuxbridge_agent_config*]
+#   (optional) Manage configuration of linuxbridge_agent.ini
+#
 #   NOTE: The configuration MUST NOT be already handled by this module
 #   or Puppet catalog compilation will fail with duplicate resources.
 #
@@ -103,7 +103,6 @@ class neutron::config (
   $api_paste_ini                 = {},
   $ovs_agent_config              = {},
   $sriov_agent_config            = {},
-  $linuxbridge_agent_config      = {},
   $macvtap_agent_config          = {},
   $bgpvpn_bagpipe_config         = {},
   $bgpvpn_service_config         = {},
@@ -124,6 +123,7 @@ class neutron::config (
   $plugin_nvp_config             = undef,
   $plugin_linuxbridge_config     = undef,
   $plugin_nsx_config             = undef,
+  $linuxbridge_agent_config      = undef,
 ) {
 
   include neutron::deps
@@ -143,11 +143,18 @@ class neutron::config (
     $plugin_nsx_config_real = {}
   }
 
+  if $linuxbridge_agent_config != undef {
+    warning('The linuxbridge_agent_config parameter is deprecated.')
+    $linuxbridge_agent_config_real = $linuxbridge_agent_config
+  } else {
+    $linuxbridge_agent_config_real = {}
+  }
+
   validate_legacy(Hash, 'validate_hash', $server_config)
   validate_legacy(Hash, 'validate_hash', $api_paste_ini)
   validate_legacy(Hash, 'validate_hash', $ovs_agent_config)
   validate_legacy(Hash, 'validate_hash', $sriov_agent_config)
-  validate_legacy(Hash, 'validate_hash', $linuxbridge_agent_config)
+  validate_legacy(Hash, 'validate_hash', $linuxbridge_agent_config_real)
   validate_legacy(Hash, 'validate_hash', $macvtap_agent_config)
   validate_legacy(Hash, 'validate_hash', $bgpvpn_bagpipe_config)
   validate_legacy(Hash, 'validate_hash', $bgpvpn_service_config)
@@ -170,7 +177,7 @@ class neutron::config (
   create_resources('neutron_api_paste_ini', $api_paste_ini)
   create_resources('neutron_agent_ovs', $ovs_agent_config)
   create_resources('neutron_sriov_agent_config', $sriov_agent_config)
-  create_resources('neutron_agent_linuxbridge', $linuxbridge_agent_config)
+  create_resources('neutron_agent_linuxbridge', $linuxbridge_agent_config_real)
   create_resources('neutron_agent_macvtap', $macvtap_agent_config)
   create_resources('neutron_bgpvpn_bagpipe_config', $bgpvpn_bagpipe_config)
   create_resources('neutron_bgpvpn_service_config', $bgpvpn_service_config)

manifests/plugins/ml2.pp

@@ -48,7 +48,7 @@
 #   Should be an array that can have these elements:
 #   logger, test, linuxbridge, openvswitch, hyperv, ncs, arista, cisco_nexus,
 #   l2population, sriovnicswitch, macvtap
-#   Default to ['openvswitch', 'linuxbridge'].
+#   Default to ['openvswitch'].
 #
 # [*flat_networks*]
 #   (optional) List of physical_network names with which flat networks
@@ -127,7 +127,7 @@ class neutron::plugins::ml2 (
   $type_drivers              = ['local', 'flat', 'vlan', 'gre', 'vxlan', 'geneve'],
   $extension_drivers         = $::os_service_default,
   $tenant_network_types      = ['local', 'flat', 'vlan', 'gre', 'vxlan'],
-  $mechanism_drivers         = ['openvswitch', 'linuxbridge'],
+  $mechanism_drivers         = ['openvswitch'],
   $flat_networks             = '*',
   $network_vlan_ranges       = 'physnet1:1000:2999',
   $tunnel_id_ranges          = '20:100',

releasenotes/notes/deprecate-linuxbridge-c70a64f210cca859.yaml

@@ -0,0 +1,10 @@
+---
+upgrade:
+  - |
+    The linuxbridge mechanism driver is no longer enabled by default.
+
+deprecations:
+  - |
+    Support for the linuxbridge mechanism driver has been deprecated.
+    The feature is now marked as an experimental one in Neutron and is no
+    longer actively maintained.

spec/classes/neutron_plugins_ml2_spec.rb

@@ -31,7 +31,7 @@ describe 'neutron::plugins::ml2' do
     {
       :type_drivers          => ['local', 'flat', 'vlan', 'gre', 'vxlan', 'geneve'],
       :tenant_network_types  => ['local', 'flat', 'vlan', 'gre', 'vxlan'],
-      :mechanism_drivers     => ['openvswitch', 'linuxbridge'],
+      :mechanism_drivers     => ['openvswitch'],
       :flat_networks         => '*',
       :network_vlan_ranges   => '10:50',
       :tunnel_id_ranges      => '20:100',