Maintenance method to update the LRP from GC to HCG

The new maintenance method
``migrate_lrp_gateway_chassis_to_ha_chassis_group``, replaces the
``Logical_Router_Port`` ``Gateway_Chassis`` with the equivalent
``HA_Chassis_Group``, that is the preferred method for HA scheduling in
OVN, as reported in the LP bug.

Partial-Bug: #2092271
Signed-off-by: Rodolfo Alonso Hernandez <[email protected]>
Change-Id: I8994415f97bca575b7104824ef889da0235c9a8b

Author: ralonsoh

neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/maintenance.py

@@ -1160,6 +1160,41 @@ def update_qos_fip_rule_priority(self):
 
         raise periodics.NeverAgain()
 
+    # TODO(ralonsoh): Remove this method in F+3 cycle (2nd next SLURP release)
+    @has_lock_periodic(
+        periodic_run_limit=ovn_const.MAINTENANCE_TASK_RETRY_LIMIT,
+        spacing=ovn_const.MAINTENANCE_ONE_RUN_TASK_SPACING,
+        run_immediately=True)
+    def migrate_lrp_gateway_chassis_to_ha_chassis_group(self):
+        """Migrate the LRP Gateway_Chassis to HA_Chassis_Group"""
+        with self._nb_idl.transaction(check_error=True) as txn:
+            for lrp in self._nb_idl.db_list_rows(
+                    'Logical_Router_Port').execute(check_error=True):
+                if not lrp.gateway_chassis:
+                    continue
+
+                chassis_prio = {}
+                for gc in lrp.gateway_chassis:
+                    chassis_prio[gc.chassis_name] = gc.priority
+                r_name = lrp.external_ids.get(
+                    ovn_const.OVN_ROUTER_NAME_EXT_ID_KEY)
+                if not r_name:
+                    LOG.warning(f'Logical_Router_Port {lrp.name} does not '
+                                'have the router name in external_ids.')
+                    continue
+
+                # Add the new HA_Chassis_Group and assign to the LRP.
+                hcg_cmd = txn.add(self._nb_idl.ha_chassis_group_with_hc_add(
+                    r_name, chassis_prio, may_exist=True))
+                txn.add(self._nb_idl.db_set(
+                    'Logical_Router_Port', lrp.uuid,
+                    ('ha_chassis_group', hcg_cmd)))
+                # Unset the Gateway_Chassis in the LRP.
+                txn.add(self._nb_idl.db_clear(
+                    'Logical_Router_Port', lrp.uuid, 'gateway_chassis'))
+
+        raise periodics.NeverAgain()
+
 
 class HashRingHealthCheckPeriodics:
 

neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_maintenance.py

@@ -27,6 +27,7 @@
 from neutron_lib import constants as n_const
 from neutron_lib import context as n_context
 from neutron_lib.exceptions import l3 as lib_l3_exc
+from neutron_lib.utils import net as net_utils
 from oslo_utils import uuidutils
 from sqlalchemy.dialects.mysql import dialect as mysql_dialect
 
@@ -1480,6 +1481,44 @@ def test_update_qos_fip_rule_priority(self):
             else:
                 self.assertEqual(def_prio, qos_rule.priority)
 
+    def test_migrate_lrp_gateway_chassis_to_ha_chassis_group(self):
+        mac = next(net_utils.random_mac_generator(['ca', 'fe', 'ca', 'fe']))
+        networks = ['192.0.2.0/24']
+        lr_name = uuidutils.generate_uuid()
+        lrp_name = uuidutils.generate_uuid()
+        gateway_chassis = ['gw_ch1', 'gw_ch2', 'gw_ch3']
+
+        self.nb_api.lr_add(lr_name).execute(check_error=True)
+        ext_ids = {ovn_const.OVN_ROUTER_NAME_EXT_ID_KEY: lr_name}
+        self.nb_api.add_lrouter_port(
+            lrp_name, lr_name, mac=mac,
+            networks=networks, gateway_chassis=gateway_chassis,
+            external_ids=ext_ids).execute(check_error=True)
+
+        hcg = self.nb_api.lookup('HA_Chassis_Group', lr_name, default=None)
+        self.assertIsNone(hcg)
+        lr = self.nb_api.lookup('Logical_Router_Port', lrp_name)
+        chassis_prio = {}
+        for gc in lr.gateway_chassis:
+            chassis_prio[gc.chassis_name] = gc.priority
+
+        self.assertRaises(
+            periodics.NeverAgain,
+            self.maint.migrate_lrp_gateway_chassis_to_ha_chassis_group)
+
+        hcg = self.nb_api.lookup('HA_Chassis_Group', lr_name, default=None)
+        self.assertEqual(len(chassis_prio), len(hcg.ha_chassis))
+        for ha_chassis in hcg.ha_chassis:
+            try:
+                # The priority and the chassis_name of the former
+                # Gateway_Chassis registers must match the new HA_Chassis ones.
+                self.assertEqual(ha_chassis.priority,
+                                 chassis_prio.pop(ha_chassis.chassis_name))
+            except KeyError:
+                self.fail(f'HA_Chassis with chassis name '
+                          f'{ha_chassis.chassis_name} not present in the '
+                          f'chassis list')
+
 
 class TestLogMaintenance(_TestMaintenanceHelper,
                          test_log_driver.LogApiTestCaseBase):