Revert "Revert "Fix for fast/cold-boot: call db_migrator only after o…

…ld config is loaded (sonic-net#14933)" (sonic-net#15464)" (sonic-net#15684)

This reverts commit 9649a44.

files/build_templates/docker_image_ctl.j2

@@ -257,10 +257,18 @@ function postStartAction()
  $SONIC_DB_CLI CONFIG_DB SET "CONFIG_DB_INITIALIZED" "1"
  fi
 
- if [[ -x /usr/local/bin/db_migrator.py ]]; then
- # Migrate the DB to the latest schema version if needed
- if [ -z "$DEV" ]; then
- /usr/local/bin/db_migrator.py -o migrate
+ if [ -e /tmp/pending_config_migration ]; then
+ # this is first boot to a new image, config-setup execution is pending.
+ # For fast/cold reboot case, DB contains nothing at this point
+ # Call db_migrator after config-setup loads the config (from old config or minigraph)
+ echo "Delaying db_migrator until config migration is over"
+ else
+ # this is not a first time boot to a new image. Datbase container starts w/ old pre-existing config
+ if [[ -x /usr/local/bin/db_migrator.py ]]; then
+ # Migrate the DB to the latest schema version if needed
+ if [ -z "$DEV" ]; then
+ /usr/local/bin/db_migrator.py -o migrate
+ fi
  fi
  fi
  # Add redis UDS to the redis group and give read/write access to the group

files/image_config/config-setup/config-setup

@@ -304,6 +304,16 @@ check_all_config_db_present()
  return 0 
 }
 
+# DB schema is subject to change between two images
+# Perform DB schema migration after loading backup config from previous image
+do_db_migration()
+{
+ if [[ -x /usr/local/bin/db_migrator.py ]]; then
+ # Migrate the DB to the latest schema version if needed
+ /usr/local/bin/db_migrator.py -o migrate
+ fi
+}
+
 # Perform configuration migration from backup copy.
 # - This step is performed when a new image is installed and SONiC switch boots into it
 do_config_migration()
@@ -326,16 +336,19 @@ do_config_migration()
  if [ x"${WARM_BOOT}" == x"true" ]; then
  echo "Warm reboot detected..."
  disable_updategraph
+ do_db_migration
  rm -f /tmp/pending_config_migration
  exit 0
  elif check_all_config_db_present; then
  echo "Use config_db.json from old system..."
  reload_configdb
+ do_db_migration
  # Disable updategraph
  disable_updategraph
  elif [ -r ${MINGRAPH_FILE} ]; then
  echo "Use minigraph.xml from old system..."
  reload_minigraph
+ do_db_migration
  # Disable updategraph
  disable_updategraph
  else