Run db_migrator for non first-time reboots

files/build_templates/docker_image_ctl.j2

@@ -251,17 +251,14 @@ function postStartAction()
             fi
         fi
 
-        if [ -e /tmp/pending_config_migration ] || [ -e /tmp/pending_config_initialization ]; then
-            # this is first boot to a new image, config-setup execution is pending.
-            # for warmboot case, DB is loaded but migration is still pending
-            # For firstbboot/fast/cold reboot case, DB contains nothing at this point
-            # unset CONFIG_DB_INITIALIZED to indicate pending config load and migration
-            # This flag will be set to "1" after DB migration/initialization is completed as part of config-setup
-            $SONIC_DB_CLI CONFIG_DB SET "CONFIG_DB_INITIALIZED" "0"
-        else
-            # set CONFIG_DB_INITIALIZED to indicate end of config load and migration
-            $SONIC_DB_CLI CONFIG_DB SET "CONFIG_DB_INITIALIZED" "1"
-        fi
+        # First boot to a new image: config-setup execution is pending.
+        # Warmboot: DB is loaded but migration is still pending
+        # firstbboot/fast/cold reboot: DB contains nothing at this point
+        # successive reboot: DB might contain a custom config_db json. Migration pending
+        # unset CONFIG_DB_INITIALIZED to indicate pending config load and/or migration
+        # This flag will be set to "1" after DB migration/initialization is completed as part of config-setup
+        $SONIC_DB_CLI CONFIG_DB SET "CONFIG_DB_INITIALIZED" "0"
+
         # Add redis UDS to the redis group and give read/write access to the group
         REDIS_SOCK="/var/run/redis${DEV}/redis.sock"
     else

files/image_config/config-setup/config-setup

@@ -422,6 +422,8 @@ boot_config()
     check_system_warm_boot
     if [ -e /tmp/pending_config_migration ] || [ -e  ${CONFIG_SETUP_POST_MIGRATION_FLAG} ]; then
         do_config_migration
+    else
+        do_db_migration
     fi
 
     # For multi-npu platfrom we don't support config initialization. Assumption
@@ -434,6 +436,8 @@ boot_config()
 
     if [ -e /tmp/pending_config_initialization ] || [ -e  ${CONFIG_SETUP_INITIALIZATION_FLAG} ]; then
         do_config_initialization
+    else
+        do_db_migration
     fi
 
     # If no startup configuration is found, create a configuration to be used