ILM Index Lifecycle

Hi can i know if ilm_rollover_alias not speificed, will it take index name as alias?

      index => "my_index"
      ilm_pattern => "{now/d{yyyyMMdd}}-00001"

so it will be
my_index-20210823-00001
?

If ILM is enabled then the index option is ignored and the default ilm_rollover_alias is logstash/ecs-logstash.

can we use index tempalte to group index into 1 and use a pattern to att date at end ?