Currently from my application server (linux) the below is the format of the command that I use to connect to Elastic search which runs on a different server (linux) using curl
curl --cacert certs/ca.crt --user elastic:password -X GET "https://elastic-server.env.domain.business.com:19200/_cat/indices?pretty=true"
Note: that ca.crt is present within the certs directory path
If I am installing Kibana on a different server(linux) than the ones that the Elastic search is running on (linux server) how should I configure the kibana.yml to include the ca.crt for all the requests that Kibana makes because without a valid certificate in the request the Elastic search will not respond.