Remove timer from FAST_REBOOT STATE_DB entry and use finalizer

scripts/db_migrator.py

@@ -45,7 +45,7 @@ def __init__(self, namespace, socket=None):
                      none-zero values.
               build: sequentially increase within a minor version domain.
         """
-        self.CURRENT_VERSION = 'version_4_0_0'
+        self.CURRENT_VERSION = 'version_4_0_1'
 
         self.TABLE_NAME      = 'VERSIONS'
         self.TABLE_KEY       = 'DATABASE'
@@ -850,9 +850,21 @@ def version_3_0_6(self):
     def version_4_0_0(self):
         """
         Version 4_0_0.
-        This is the latest version for master branch
         """
         log.log_info('Handling version_4_0_0')
+        # Update state-db fast-reboot entry to enable if set to enable fast-reboot finalizer when using upgrade with fast-reboot
+        fastreboot_state = self.stateDB.get(self.stateDB.STATE_DB, 'FAST_REBOOT|system', '1')
+        if fastreboot_state == 'true':
+            self.stateDB.set(self.stateDB.STATE_DB, 'FAST_REBOOT|system', 'enable')
+        self.set_version('version_4_0_1')
+        return None
+
+    def version_4_0_1(self):
+        """
+        Version 4_0_1.
+        This is the latest version for master branch
+        """
+        log.log_info('Handling version_4_0_1')
         return None
 
     def get_version(self):

scripts/fast-reboot

@@ -148,7 +148,7 @@ function clear_boot()
 
     #clear_fast_boot
     if [[ "$REBOOT_TYPE" = "fast-reboot" ]]; then
-        sonic-db-cli STATE_DB DEL "FAST_REBOOT|system" &>/dev/null || /bin/true
+        sonic-db-cli STATE_DB SET "FAST_REBOOT|system" "disable" &>/dev/null || /bin/true
     fi
 }
 
@@ -532,7 +532,7 @@ case "$REBOOT_TYPE" in
         check_warm_restart_in_progress
         BOOT_TYPE_ARG=$REBOOT_TYPE
         trap clear_boot EXIT HUP INT QUIT TERM KILL ABRT ALRM
-        sonic-db-cli STATE_DB SET "FAST_REBOOT|system" "1" "EX" "210" &>/dev/null
+        sonic-db-cli STATE_DB SET "FAST_REBOOT|system" "enable" &>/dev/null
         config warm_restart enable system
         ;;
     "warm-reboot")

sonic-utilities-data/templates/service_mgmt.sh.j2

@@ -51,7 +51,8 @@ function check_warm_boot()
 
 function check_fast_boot()
 {
-    if [[ $($SONIC_DB_CLI STATE_DB GET "FAST_REBOOT|system") == "1" ]]; then
+    SYSTEM_FAST_REBOOT=`sonic-db-cli STATE_DB GET "FAST_REBOOT|system"`
+    if [[ ${SYSTEM_FAST_REBOOT} == "enable" ]]; then
         FAST_BOOT="true"
     else
         FAST_BOOT="false"