Use HA_Chassis_Group in the OVN L3 scheduler

TODO:
* Testing

NOTE: this method cannot be merged alone, it would need
``schedule_unhosted_gateways`` too and a migration strategy (a
maintenance method)

The NB API method ``schedule_new_gateway`` now creates a
``HA_Chassis_Group`` and its ``HA_Chassis`` registers, and associates it
to the gateway ``Logical_Router_Port``. The usage og ``Gateway_Chassis``
is deprecated.

Partial-Bug: #2092271
Change-Id: If38f405428a8b27bf551db48c4e96d75deeb09fc
Signed-off-by: Rodolfo Alonso Hernandez <[email protected]>

Author: ralonsoh

neutron/common/ovn/utils.py

@@ -903,6 +903,16 @@ def get_chassis_without_azs(chassis_list):
             get_chassis_availability_zones(ch)}
 
 
+def get_chassis_priority(chassis_list):
+    """Given a chassis list, returns a dictionary with chassis name and prio
+
+    The chassis list is ordered according to the priority: the first one is the
+    highest priority chassis, the last one is the least priority chassis.
+    """
+    return {chassis: prio + 1 for prio, chassis
+            in enumerate(reversed(chassis_list))}
+
+
 def parse_ovn_lb_port_forwarding(ovn_rtr_lb_pfs):
     """Return a dictionary compatible with port forwarding from OVN lb."""
     result = {}

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

@@ -432,9 +432,12 @@ def run_idl(self, txn):
                 # the top.
                 index = chassis.index(primary)
                 chassis[0], chassis[index] = chassis[index], chassis[0]
-        setattr(
-            lrouter_port,
-            *_add_gateway_chassis(self.api, txn, self.g_name, chassis))
+        chassis_priority = utils.get_chassis_priority(chassis)
+        lrouter_name = lrouter_port.external_ids[
+            ovn_const.OVN_ROUTER_NAME_EXT_ID_KEY]
+        hcg = _sync_ha_chassis_group(txn, self.api, lrouter_name,
+                                     chassis_priority, may_exist=True)
+        setattr(lrouter_port, 'ha_chassis_group', ovsdbapp_utils.get_uuid(hcg))
 
 
 class ScheduleNewGatewayCommand(command.BaseCommand):
@@ -459,8 +462,11 @@ def run_idl(self, txn):
             self.api, self.sb_api, self.g_name, candidates=candidates,
             target_lrouter=lrouter)
         if chassis:
-            setattr(lrouter_port,
-                    *_add_gateway_chassis(self.api, txn, self.g_name, chassis))
+            chassis_priority = utils.get_chassis_priority(chassis)
+            hcg = _sync_ha_chassis_group(txn, self.api, self.lrouter_name,
+                                         chassis_priority, may_exist=True)
+            setattr(lrouter_port, 'ha_chassis_group',
+                    ovsdbapp_utils.get_uuid(hcg))
 
 
 class LrDelCommand(ovn_nb_commands.LrDelCommand):
@@ -1053,15 +1059,17 @@ def run_idl(self, txn):
         # Remove the router pinning to a chassis (if any).
         lrouter.delkey('options', 'chassis')
 
-        # Remove the HA_Chassis_Group of the router (if any).
+        for gw_port in self.api.get_lrouter_gw_ports(lrouter.name):
+            gw_port.ha_chassis_group = []
+            lrouter.delvalue('ports', gw_port)
+
+        # Remove the HA_Chassis_Group of the router (if any), after
+        # removing it from the gateway Logical_Router_Ports.
         hcg = self.api.lookup('HA_Chassis_Group',
                               lrouter.name, default=None)
         if hcg:
             hcg.delete()
 
-        for gw_port in self.api.get_lrouter_gw_ports(lrouter.name):
-            lrouter.delvalue('ports', gw_port)
-
 
 class SetLSwitchPortToVirtualTypeCommand(command.BaseCommand):
     def __init__(self, api, lport, vip, parent, if_exists):