[202211] [db_migrator.py] Fix issue while upgrading from 202205 to 20…

…2211 via fast reboot (#2962)

Backport #2948 to 202211

What I did
Fix issue while upgrading from 202205 to 202211 via fast reboot. This issue is caused by a mismatch version handling for fast reboot in db_migrator.

In 202205, the db migrator for fast reboot flag handling is 3_0_5:

sonic-utilities/scripts/db_migrator.py

Line 920 in 56a1ae2

 def version_3_0_5(self): 
However, in master(202211), the db migrator for fast reboot flag handling is 4_0_0:

sonic-utilities/scripts/db_migrator.py

Line 993 in 7435b1c

 def version_4_0_0(self): 
This mismatch causes an incorrect sequence like this:

1. User issue fast-reboot under 202205
2. fast-reboot script set fast reboot flag by command "sonic-db-cli STATE_DB HSET "FAST_RESTART_ENABLE_TABLE|system" "enable" "true" &>/dev/null"
3. system boot to 202211
4. db_migrator found the database version is 3_0_6, it will run 4_0_0, however, it found FAST_REBOOT|system does not exist, and it set  FAST_RESTART_ENABLE_TABLE|system enable to false
5. system incorrectly performs cold reboot
How I did it
in db migrator if we see there is FAST_RESTART_ENABLE_TABLE already, we should skip fast reboot flag migration

How to verify it
unit test
manual test

scripts/db_migrator.py

@@ -946,12 +946,14 @@ def version_4_0_0(self):
         # reading FAST_REBOOT table can't be done with stateDB.get as it uses hget behind the scenes and the table structure is
         # not using hash and won't work.
         # FAST_REBOOT table exists only if fast-reboot was triggered.
-        keys = self.stateDB.keys(self.stateDB.STATE_DB, "FAST_REBOOT|system")
-        if keys:
-            enable_state = 'true'
-        else:
-            enable_state = 'false'
-        self.stateDB.set(self.stateDB.STATE_DB, 'FAST_RESTART_ENABLE_TABLE|system', 'enable', enable_state)
+        keys = self.stateDB.keys(self.stateDB.STATE_DB, "FAST_RESTART_ENABLE_TABLE|system")
+        if not keys:
+            keys = self.stateDB.keys(self.stateDB.STATE_DB, "FAST_REBOOT|system")
+            if keys:
+                enable_state = 'true'
+            else:
+                enable_state = 'false'
+            self.stateDB.set(self.stateDB.STATE_DB, 'FAST_RESTART_ENABLE_TABLE|system', 'enable', enable_state)
         self.set_version('version_4_0_1')
         return 'version_4_0_1'
 

tests/db_migrator_input/state_db/fast_reboot_upgrade_from_202205.json

@@ -0,0 +1,5 @@
+{
+	"FAST_RESTART_ENABLE_TABLE|system": {
+		"enable": "true"
+	}
+}

tests/db_migrator_test.py

@@ -483,6 +483,25 @@ def test_rename_fast_reboot_table_check_enable(self):
         diff = DeepDiff(resulting_table, expected_table, ignore_order=True)
         assert not diff
 
+    def test_ignore_rename_fast_reboot_table(self):
+        device_info.get_sonic_version_info = get_sonic_version_info_mlnx
+        dbconnector.dedicated_dbs['STATE_DB'] = os.path.join(mock_db_path, 'state_db', 'fast_reboot_upgrade_from_202205')
+        dbconnector.dedicated_dbs['CONFIG_DB'] = os.path.join(mock_db_path, 'config_db', 'empty-config-input')
+
+        import db_migrator
+        dbmgtr = db_migrator.DBMigrator(None)
+        dbmgtr.migrate()
+
+        dbconnector.dedicated_dbs['STATE_DB'] = os.path.join(mock_db_path, 'state_db', 'fast_reboot_upgrade_from_202205')
+        expected_db = SonicV2Connector(host='127.0.0.1')
+        expected_db.connect(expected_db.STATE_DB)
+
+        resulting_table = dbmgtr.stateDB.get_all(dbmgtr.stateDB.STATE_DB, 'FAST_RESTART_ENABLE_TABLE|system')
+        expected_table = expected_db.get_all(expected_db.STATE_DB, 'FAST_RESTART_ENABLE_TABLE|system')
+
+        diff = DeepDiff(resulting_table, expected_table, ignore_order=True)
+        assert not diff
+
 class TestWarmUpgrade_to_2_0_2(object):
     @classmethod
     def setup_class(cls):