Support accessing InfluxDB via HAProxy

This change allows access to InfluxDB via HAProxy on the internal
network.

If HA is required the Enterprise version of InfluxDB will need to
be installed. This could be implemented by customising the InfluxDB
Docker file.

There are other alternatives to HA, such as the InfluxDB Relay [1].
Support for this is considered to be outside of the scope of this
bugfix.

[1] https://docs.openstack.org/developer/performance-docs/
    methodologies/monitoring/influxha.html

Closes-Bug: #1751283
Change-Id: I4624efbd99c0cddd1361f2438866ad3a82e5557b

ansible/roles/grafana/defaults/main.yml

@@ -31,7 +31,7 @@ grafana_data_sources:
       database: "telegraf"
       name: "telegraf"
       type: "influxdb"
-      url: "{{ internal_protocol }}://{{ api_interface_address }}:{{ influxdb_http_port }}"
+      url: "{{ internal_protocol }}://{{ kolla_internal_vip_address }}:{{ influxdb_http_port }}"
       access: "proxy"
       basicAuth: false
   elasticsearch:

ansible/roles/haproxy/templates/haproxy.cfg.j2

@@ -153,6 +153,20 @@ listen glance_api_external
 {% endif %}
 {% endif %}
 
+{% if enable_influxdb | bool %}
+listen influxdb_admin
+  bind {{ kolla_internal_vip_address }}:{{ influxdb_admin_port }}
+{% for host in groups['influxdb'] %}
+  server {{ hostvars[host]['ansible_hostname'] }} {{ hostvars[host]['ansible_' + hostvars[host]['api_interface']]['ipv4']['address'] }}:{{ influxdb_admin_port }} check inter 2000 rise 2 fall 5
+{% endfor %}
+
+listen influxdb_http
+  bind {{ kolla_internal_vip_address }}:{{ influxdb_http_port }}
+{% for host in groups['influxdb'] %}
+  server {{ hostvars[host]['ansible_hostname'] }} {{ hostvars[host]['ansible_' + hostvars[host]['api_interface']]['ipv4']['address'] }}:{{ influxdb_http_port }} check inter 2000 rise 2 fall 5
+{% endfor %}
+{% endif %}
+
 {% if enable_nova | bool %}
 listen nova_api
   bind {{ kolla_internal_vip_address }}:{{ nova_api_port }}