Mark "ipv6_pd_enabled" as deprecated and experimental.

This functionality will be kept in the code as experimental as long
as no bugs are reported againts this feature.

This patch also marks the config option "ipv6_pd_enabled" as
experimental. In order to enable this flag, it is needed to configure
the "experimental.ipv6_pd_enabled" flag too.

Related-Bug: #1916428
Change-Id: I27aeed74f308d5bdf0210e76d9557f95b66c71bf

neutron/conf/common.py

@@ -77,7 +77,12 @@ core_opts = [
                        "without providing a CIDR or subnetpool ID will be "
                        "given a CIDR via the Prefix Delegation mechanism. "
                        "Note that enabling PD will override the behavior of "
-                       "the default IPv6 subnetpool.")),
+                       "the default IPv6 subnetpool."),
+                deprecated_for_removal=True,
+                deprecated_since='2023.2',
+                deprecated_reason=("The Dibbler client used for this feature "
+                                   "is no longer maintained. See LP#1916428"),
+                ),
     cfg.IntOpt('dhcp_lease_duration', default=86400,
                help=_("DHCP lease duration (in seconds). Use -1 to tell "
                       "dnsmasq to use infinite lease times.")),

neutron/conf/experimental.py

@@ -17,11 +17,16 @@ from neutron._i18n import _
 
 EXPERIMENTAL_CFG_GROUP = 'experimental'
 EXPERIMENTAL_LINUXBRIDGE = 'linuxbridge'
+EXPERIMENTAL_IPV6_PD = 'ipv6_pd_enabled'
 experimental_opts = [
     cfg.BoolOpt(EXPERIMENTAL_LINUXBRIDGE,
                 default=False,
                 help=_('Enable execution of the experimental Linuxbridge '
                        'agent.')),
+    cfg.BoolOpt(EXPERIMENTAL_IPV6_PD,
+                default=False,
+                help=_('Enable execution of the experimental IPv6 Prefix '
+                       'Delegation functionality in the L3 agent.')),
 ]
 
 

neutron/db/db_base_plugin_v2.py

@@ -51,8 +51,10 @@ from sqlalchemy import not_
 from neutron._i18n import _
 from neutron.api.rpc.agentnotifiers import l3_rpc_agent_api
 from neutron.common import _constants
+from neutron.common import experimental
 from neutron.common import ipv6_utils
 from neutron.common import utils
+from neutron.conf import experimental as c_exp
 from neutron.db import db_base_plugin_common
 from neutron.db import ipam_pluggable_backend
 from neutron.db import models_v2
@@ -156,7 +158,17 @@ class NeutronDbPluginV2(db_base_plugin_common.DbBasePluginCommon,
             result_filters=None)
         return super(NeutronDbPluginV2, cls).__new__(cls, *args, **kwargs)
 
+    @staticmethod
+    def _validate_ipv6_pd():
+        try:
+            if cfg.CONF.ipv6_pd_enabled:
+                experimental.validate_experimental_enabled(
+                    c_exp.EXPERIMENTAL_IPV6_PD)
+        except cfg.NoSuchOptError:
+            return
+
     def __init__(self):
+        self._validate_ipv6_pd()
         self.set_ipam_backend()
         if (cfg.CONF.notify_nova_on_port_status_changes or
                 cfg.CONF.notify_nova_on_port_data_changes):

releasenotes/notes/mark_ipv6_pd_enabled_as_experimental-c9bfe343a0beb334.yaml

@@ -0,0 +1,7 @@
+---
+deprecations:
+  - |
+    "ipv6_pd_enabled" has been marked as deprecated and marked as experimental.
+    To continue using it, deployers have to set to True the "ipv6_pd_enabled"
+    option in the "experimental" section of neutron.conf. See
+    `Dibbler project concluded <https://bugs.launchpad.net/neutron/+bug/1916428>`_.