[OVN] Remove maintenance method "remove_duplicated_chassis_registers"

Since OVN 21.03.0 [1], ovn-controller no longer will try to reuse the
stale Chassis/Chassis_Private records but will try to create new ones.
If the stale records have no been manually deleted and ovn-controller
tries to register a new Chassis with the same values, the transaction will
fail.

[1]fc359bfe93

Closes-Bug: #2073613
Change-Id: I2f14558b0910fed03fe0243c4daa33947feeedcb

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

@@ -1011,63 +1011,6 @@ class DBInconsistenciesPeriodics(SchemaAwarePeriodicsBase):
                                                    from_reload=True)
         raise periodics.NeverAgain()
 
-    @periodics.periodic(spacing=300, run_immediately=True)
-    def remove_duplicated_chassis_registers(self):
-        """Remove the "Chassis" and "Chassis_Private" duplicated registers.
-
-        When the ovn-controller service of a node is updated and the system-id
-        is changed, if the old service is not stopped gracefully, it will leave
-        a "Chassis" and a "Chassis_Private" registers on the OVN SB database.
-        These leftovers must be removed.
-
-        NOTE: this method is executed every 5 minutes. If a new chassis is
-        added, this method will perform again the clean-up process.
-
-        NOTE: this method can be executed only if the OVN SB has the
-        "Chassis_Private" table. Otherwise, is not possible to find out which
-        register is newer and thus must be kept in the database.
-        """
-        if not self._sb_idl.is_table_present('Chassis_Private'):
-            raise periodics.NeverAgain()
-
-        if not self.has_lock:
-            return
-
-        # dup_chassis_port_host = {host_name: [(ch1, ch_private1),
-        #                                      (ch2, ch_private2), ... ]}
-        dup_chassis_port_host = {}
-        chassis = self._sb_idl.chassis_list().execute(check_error=True)
-        chassis_hostnames = {ch.hostname for ch in chassis}
-        # Find the duplicated "Chassis" and "Chassis_Private" registers,
-        # comparing the hostname.
-        for hostname in chassis_hostnames:
-            ch_list = []
-            # Find these chassis matching the hostname and create a list.
-            for ch in (ch for ch in chassis if ch.hostname == hostname):
-                ch_private = self._sb_idl.lookup('Chassis_Private', ch.name,
-                                                 default=None)
-                if ch_private:
-                    ch_list.append((ch, ch_private))
-
-            # If the chassis list > 1, then we have duplicated chassis.
-            if len(ch_list) > 1:
-                # Order ch_list by Chassis_Private.nb_cfg_timestamp, from newer
-                # (greater value) to older.
-                ch_list.sort(key=lambda x: x[1].nb_cfg_timestamp, reverse=True)
-                dup_chassis_port_host[hostname] = ch_list
-
-        if not dup_chassis_port_host:
-            return
-
-        # Remove the "Chassis" and "Chassis_Private" registers with the
-        # older Chassis_Private.nb_cfg_timestamp.
-        with self._sb_idl.transaction(check_error=True) as txn:
-            for ch_list in dup_chassis_port_host.values():
-                # The first item is skipped, this is the newest element.
-                for ch, ch_private in ch_list[1:]:
-                    for table in ('Chassis_Private', 'Chassis'):
-                        txn.add(self._sb_idl.db_destroy(table, ch.name))
-
     @has_lock_periodic(spacing=86400, run_immediately=True)
     def cleanup_old_hash_ring_nodes(self):
         """Daily task to cleanup old stable Hash Ring node entries.

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

@@ -1014,64 +1014,6 @@ class TestMaintenance(_TestMaintenanceHelper):
         lsp = self.nb_api.lookup('Logical_Switch_Port', p1['id'])
         self.assertEqual(hcg_uuid, lsp.ha_chassis_group[0].uuid)
 
-    def test_remove_duplicated_chassis_registers(self):
-        hostnames = ['host1', 'host2']
-        for hostname in hostnames:
-            for _ in range(3):
-                self.add_fake_chassis(hostname)
-
-        chassis = self.sb_api.chassis_list().execute(check_error=True)
-        self.assertEqual(6, len(chassis))
-        # Make the chassis private timestamp different
-        for idx, ch in enumerate(chassis):
-            self.sb_api.db_set('Chassis_Private', ch.name,
-                               ('nb_cfg_timestamp', idx)).execute()
-
-        ch_private_dict = {}  # host: [ch_private1, ch_private2, ...]
-        for hostname in hostnames:
-            ch_private_list = []
-            for ch in (ch for ch in chassis if ch.hostname == hostname):
-                ch_private = self.sb_api.lookup('Chassis_Private', ch.name,
-                                                default=None)
-                if ch_private:
-                    # One of the "Chassis_Private" has been deleted on purpose
-                    # in this test.
-                    ch_private_list.append(ch_private)
-            ch_private_list.sort(key=lambda x: x.nb_cfg_timestamp,
-                                 reverse=True)
-            ch_private_dict[hostname] = ch_private_list
-
-        self.maint.remove_duplicated_chassis_registers()
-        chassis_result = self.sb_api.chassis_list().execute(check_error=True)
-        self.assertEqual(2, len(chassis_result))
-        for ch in chassis_result:
-            self.assertIn(ch.hostname, hostnames)
-            hostnames.remove(ch.hostname)
-            # From ch_private_dict[ch.hostname], we retrieve the first
-            # "Chassis_Private" register because these are ordered by
-            # timestamp. The newer one (bigger timestamp) should remain in the
-            # system.
-            ch_expected = ch_private_dict[ch.hostname][0].chassis[0]
-            self.assertEqual(ch_expected.name, ch.name)
-
-    def test_remove_duplicated_chassis_registers_no_ch_private_register(self):
-        for _ in range(2):
-            self.add_fake_chassis('host1')
-
-        chassis = self.sb_api.chassis_list().execute(check_error=True)
-        self.assertEqual(2, len(chassis))
-        # Make the chassis private timestamp different
-        # Delete on of the "Chassis_Private" registers.
-        self.sb_api.db_destroy('Chassis_Private', chassis[0].name).execute()
-        self.sb_api.db_set('Chassis_Private', chassis[1].name,
-                           ('nb_cfg_timestamp', 1)).execute()
-
-        self.maint.remove_duplicated_chassis_registers()
-        chassis_result = self.sb_api.chassis_list().execute(check_error=True)
-        # Both "Chassis" registers are still in the DB because one
-        # "Chassis_Private" register was missing.
-        self.assertEqual(2, len(chassis_result))
-
     def test_configure_nb_global(self):
         def options_intersect(options1, options2):
             return bool(set(

releasenotes/notes/delete-remove-duplicated-ovn-chassis-fdac8529e7d07c33.yaml

@@ -0,0 +1,7 @@
+---
+deprecations:
+  - |
+    Removed the maintenance method ``remove_duplicated_chassis_registers``.
+    This method is no longer needed since OVN 21.03.0. For more information,
+    see the bug
+    `2073613 <https://bugs.launchpad.net/neutron/+bug/2073613>`_.