Fix updating port MAC address for active nodes

Current update fails with HTTP 500 when trying to update a bound Neutron
port. Remove the binding before update and restore it during update.

For nodes in "active" state (or with instance_uuid assigned) only allow
such update in maintenance mode. This is not a breaking change, as previously
it did not work at all.

Change-Id: I356fc0eb3702eb16b7f8e675ea416473c65af7e3
Closes-Bug: #1611744

1 files changed, 24 insertions, 0 deletions

diff --git a/ironic/dhcp/neutron.py b/ironic/dhcp/neutron.py
index 0ebe00042..021af95b7 100644
--- a/ironic/dhcp/neutron.py
+++ b/ironic/dhcp/neutron.py
@@ -70,6 +70,16 @@ class NeutronDHCPApi(base.BaseDHCP):
             LOG.exception(_LE("Failed to update Neutron port %s."), port_id)
             raise exception.FailedToUpdateDHCPOptOnPort(port_id=port_id)
 
+    def _get_binding(self, client, port_id):
+        """Get binding:host_id property from Neutron."""
+        try:
+            return client.show_port(port_id).get('port', {}).get(
+                'binding:host_id')
+        except neutron_client_exc.NeutronClientException:
+            LOG.exception(_LE('Failed to get the current binding on Neutron '
+                              'port %s.'), port_id)
+            raise exception.FailedToUpdateMacOnPort(port_id=port_id)
+
     def update_port_address(self, port_id, address, token=None):
         """Update a port's mac address.
 
@@ -78,7 +88,21 @@ class NeutronDHCPApi(base.BaseDHCP):
         :param token: optional auth token.
         :raises: FailedToUpdateMacOnPort
         """
+        client = neutron.get_client(token)
         port_req_body = {'port': {'mac_address': address}}
+
+        current_binding = self._get_binding(client, port_id)
+        if current_binding:
+            binding_clean_body = {'port': {'binding:host_id': ''}}
+            try:
+                client.update_port(port_id, binding_clean_body)
+            except neutron_client_exc.NeutronClientException:
+                LOG.exception(_LE("Failed to remove the current binding from "
+                                  "Neutron port %s."), port_id)
+                raise exception.FailedToUpdateMacOnPort(port_id=port_id)
+
+            port_req_body['port']['binding:host_id'] = current_binding
+
         try:
             neutron.get_client(token).update_port(port_id, port_req_body)
         except neutron_client_exc.NeutronClientException: