Watcher settings

Elastic Stack Elasticsearch
1

previous i created the watcher in my local server 1 elasticsearch and kibana server.

now my requirement is my cluster having 3 es nodes ,2 logstash nodes ,1 ml node,1 kibana .. how to setup watcher and email conf in elasticsearch.yml ?

  1. shall i configure email settings in elasticsearch.yml file in all 3 es nodes ? or master es node only configure ?
    2.which mandatory settings are enable in elasticsearch.yml, kibana.yml & logstash.yml

thanks in advance .

2

tell me what are prerequisites are required to setup watcher and email configuration to deploy in development