Exposed Kibana elastic endpoint

Kibana can currently only be deployed alongside an elasticsearch
coordinator node, so that it can query the cluster directly. However, in
certain situations it can be useful to keep kibana separate from
elasticsearch for e.g. resource reasons. This change allows the user to
deploy Kibana with a list of remote endpoints that it can use to query
the elastic cluster, such that no local install is required. The default
behaviour is unchanged, as the default endpoint remains the localhost.

Change-Id: Ic99b9aafd1d70b99d2088a4017e58079b5124ddc

elk_metrics_7x/roles/elastic_kibana/defaults/main.yml

@@ -25,6 +25,11 @@ kibana_server_name: "{{ ansible_hostname }}"
 kibana_index_on_elasticsearch: "http://{{ hostvars[groups['elastic-logstash'][0]]['ansible_host'] }}:{{ elastic_port}}/.kibana"
 kibana_elastic_request_timeout: 1800000
 
+# If unset, the protocol and port default to http and elastic_port
+# respectively
+kibana_elastic_endpoints:
+  - "http://127.0.0.1:{{ elastic_port }}"
+
 # The following must be set in order to to allow kibana load balancing
 # otherwise they are set individually per Kibana instance
 # The key used to encrypt Elasticsearch reports

elk_metrics_7x/roles/elastic_kibana/templates/kibana.yml.j2

@@ -25,7 +25,7 @@ server.host: {{ kibana_interface }}
 #server.name: "your-hostname"
 
 # The URLs of the Elasticsearch instances to use for all your queries.
-elasticsearch.hosts: "http://127.0.0.1:{{ elastic_port }}"
+elasticsearch.hosts: {{ kibana_elastic_endpoints  | to_json }}
 
 # When this setting's value is true Kibana uses the hostname specified in the server.host
 # setting. When the value of this setting is false, Kibana uses the hostname of the host