diff --git a/extraconfig/post_deploy/undercloud_ctlplane_network.py b/extraconfig/post_deploy/undercloud_ctlplane_network.py
index 5414885258..5f8f494c5f 100755
--- a/extraconfig/post_deploy/undercloud_ctlplane_network.py
+++ b/extraconfig/post_deploy/undercloud_ctlplane_network.py
@@ -88,8 +88,8 @@ def _neutron_subnet_create(sdk, network_id, cidr, gateway, host_routes,
                 gateway_ip=gateway,
                 enable_dhcp=True,
                 ip_version='6',
-                ipv6_address_mode='dhcpv6-stateless',
-                ipv6_ra_mode='dhcpv6-stateless',
+                ipv6_address_mode=CONF['ipv6_address_mode'],
+                ipv6_ra_mode=CONF['ipv6_address_mode'],
                 allocation_pools=allocation_pools,
                 network_id=network_id,
                 segment_id=segment_id,
diff --git a/extraconfig/post_deploy/undercloud_post.yaml b/extraconfig/post_deploy/undercloud_post.yaml
index abd4a867b2..90072d55a4 100644
--- a/extraconfig/post_deploy/undercloud_post.yaml
+++ b/extraconfig/post_deploy/undercloud_post.yaml
@@ -71,6 +71,13 @@ parameters:
     type: number
     constraints:
       - range: { min: 1000, max: 65536 }
+  UndercloudCtlplaneIPv6AddressMode:
+    default: dhcpv6-stateless
+    description: >
+      IPv6 address configuration mode for the undercloud provisioning network.
+    type: string
+    constraints:
+      - allowed_values: ['dhcpv6-stateless', 'dhcpv6-stateful']
   KeystoneRegion:
     type: string
     default: 'regionOne'
@@ -229,3 +236,4 @@ resources:
                 enable_routed_networks: {get_param: UndercloudEnableRoutedNetworks}
                 mtu: {get_param: UndercloudLocalMtu}
                 home_dir: {get_param: UndercloudHomeDir}
+                ipv6_address_mode: {get_param: UndercloudCtlplaneIPv6AddressMode}