[Fast-reboot] Set flex counters delay indicator to prevent flex count…

…ers enablement after fast-reboot (#1768)

#### What I did
Set flex counters delay indicator to prevent flex counters enablement after fast-reboot.

#### How I did it
Modify config DB json file with 'true' status for delay of flex counters indicator.

#### How to verify it
Run fast-reboot and observe counters are created only when enable_counters script is called, even if the tables are present in config DB.

counterpoll/main.py

@@ -276,18 +276,24 @@ def show():
 
     click.echo(tabulate(data, headers=header, tablefmt="simple", missingval=""))
 
-def _update_config_db(status, filename):
+def _update_config_db_flex_counter_table(status, filename):
     """ Update counter configuration in config_db file """
     with open(filename) as config_db_file:
         config_db = json.load(config_db_file)
 
     write_config_db = False
     if "FLEX_COUNTER_TABLE" in config_db:
-        for counter, counter_config in config_db["FLEX_COUNTER_TABLE"].items():
-            if "FLEX_COUNTER_STATUS" in counter_config and \
-                counter_config["FLEX_COUNTER_STATUS"] is not status:
-                counter_config["FLEX_COUNTER_STATUS"] = status
-                write_config_db = True
+        if status != "delay":
+            for counter, counter_config in config_db["FLEX_COUNTER_TABLE"].items():
+                if "FLEX_COUNTER_STATUS" in counter_config and \
+                    counter_config["FLEX_COUNTER_STATUS"] is not status:
+                    counter_config["FLEX_COUNTER_STATUS"] = status
+                    write_config_db = True
+
+        elif status == "delay":
+            write_config_db = True
+            for key in config_db["FLEX_COUNTER_TABLE"].keys():
+                config_db["FLEX_COUNTER_TABLE"][key].update({"FLEX_COUNTER_DELAY_STATUS":"true"})
 
     if write_config_db:
         with open(filename, 'w') as config_db_file:
@@ -302,11 +308,16 @@ def config_db():
 @click.argument("filename", default="/etc/sonic/config_db.json", type=click.Path(exists=True))
 def enable(filename):
     """ Enable counter configuration in config_db file """
-    _update_config_db("enable", filename)
+    _update_config_db_flex_counter_table("enable", filename)
 
 @config_db.command()
 @click.argument("filename", default="/etc/sonic/config_db.json", type=click.Path(exists=True))
 def disable(filename):
     """ Disable counter configuration in config_db file """
-    _update_config_db("disable", filename)
+    _update_config_db_flex_counter_table("disable", filename)
 
+@config_db.command()
+@click.argument("filename", default="/etc/sonic/config_db.json", type=click.Path(exists=True))
+def delay(filename):
+    """ Delay counters in config_db file """
+    _update_config_db_flex_counter_table("delay", filename)

scripts/fast-reboot

@@ -5,6 +5,7 @@ REBOOT_TIME=$(date)
 REBOOT_CAUSE_FILE="/host/reboot-cause/reboot-cause.txt"
 WARM_DIR=/host/warmboot
 REDIS_FILE=dump.rdb
+CONFIG_DB_FILE=/etc/sonic/config_db.json
 REBOOT_SCRIPT_NAME=$(basename $0)
 REBOOT_TYPE="${REBOOT_SCRIPT_NAME}"
 SHUTDOWN_ORDER_FILE="/etc/sonic/${REBOOT_TYPE}_order"
@@ -36,6 +37,7 @@ EXIT_ORCHAGENT_SHUTDOWN=10
 EXIT_SYNCD_SHUTDOWN=11
 EXIT_FAST_REBOOT_DUMP_FAILURE=12
 EXIT_FILTER_FDB_ENTRIES_FAILURE=13
+EXIT_COUNTERPOLL_DELAY_FAILURE=14
 EXIT_NO_CONTROL_PLANE_ASSISTANT=20
 EXIT_SONIC_INSTALLER_VERIFY_REBOOT=21
 
@@ -513,7 +515,6 @@ if [[ "$REBOOT_TYPE" = "fast-reboot" ]]; then
     # Dump the ARP and FDB tables to files also as default routes for both IPv4 and IPv6
     # into /host/fast-reboot
     DUMP_DIR=/host/fast-reboot
-    CONFIG_DB_FILE=/etc/sonic/config_db.json
     mkdir -p $DUMP_DIR
     FAST_REBOOT_DUMP_RC=0
     /usr/local/bin/fast-reboot-dump.py -t $DUMP_DIR || FAST_REBOOT_DUMP_RC=$?
@@ -554,6 +555,17 @@ if [[ "$REBOOT_TYPE" = "warm-reboot" || "$REBOOT_TYPE" = "fastfast-reboot" ]]; t
     fi
 fi
 
+if [[ "$REBOOT_TYPE" = "fast-reboot" ]]; then
+    COUNTERPOLL_DELAY_RC=0
+    # Delay counters in config_db.json
+    /usr/local/bin/counterpoll config-db delay $CONFIG_DB_FILE || COUNTERPOLL_DELAY_RC=$?
+    if [[ COUNTERPOLL_DELAY_RC -ne 0 ]]; then
+        error "Failed to delay counterpoll. Exit code: $COUNTERPOLL_DELAY_RC"
+        unload_kernel
+        exit "${EXIT_COUNTERPOLL_DELAY_FAILURE}"
+    fi
+fi
+
 # We are fully committed to reboot from this point on because critical
 # service will go down and we cannot recover from it.
 set +e