It seems when deleting or PUT'ing mapping templates to elasticsearch, by default, they are not captured in ES logs (tried in versions 1.7.x and 5.1.2), while deleting or creating indices, we have the logs below
[2017-04-04 09:00:02,351][INFO ][cluster.metadata] [DATA1] [my_index] deleting index
[2017-04-04 00:01:03,194][INFO ][cluster.metadata] [DATA1] [my_index_xxx] creating index, cause [auto(index api)], templates [template_xxx], shards [5]/[1], mappings [log]
How to have similar logs for mapping template activities, without changing the default logger level?