set active_directory security in elasticsearch.yml. After setting up xpack configuration in the yml file, Elastic service did not start anymore, it indicates that the [null-valued setting found for the active_directory settings. Not sure if there is something missing here.
I also try to use journalctrl to get more info but there is no other error messages to indicate what is the source of the error.
I am upgrading from 6.8.3 to 7.12.
Here is the setting for 7.12 version:
... oher settings here...