openstack-ansible-ops/elk_metrics_6x/common_task_data_node_hosts.yml

---

# storage node count is equal to the cluster size
- name: Node count fact
  set_fact:
    storage_node_count: "{{ groups['elastic-logstash'] | length }}"
  tags:
    - always

# the elasticserch cluster elects one master from all those which are marked as master-eligible
# 1 node cluster can only have one master
# 2 node clusters have 1 master-eligable nodes to avoid split-brain
# 3 node clusters have 3 master-eligable nodes
# >3 node clusters have (nodes // 2) eligable masters rounded up to the next odd number
- name: Master node count fact
  set_fact:
    master_node_count: |-
      {% set masters = 0 %}
      {% if (storage_node_count | int) < 3 %}
      {%   set masters = 1 %}
      {% elif (storage_node_count | int) == 3 %}
      {%   set masters = 3 %}
      {% else %}
      {%   set masters = (storage_node_count | int ) // 2 %}
      {%   if ((masters | int) % 2 == 0) %}
      {%     set masters = (masters | int) + 1 %}
      {%   endif %}
      {% endif %}
      {{ masters }}      
  tags:
    - always

# assign node roles
# the first 'master_node_count' hosts in groups['elastic-logstash'] become master-eligible nodes
# the first 'master_node_count' and subsequent alternate hosts in groups['elastic-logstash'] becomes data nodes
- name: Data nodes fact
  set_fact:
    data_nodes: "{{ (groups['elastic-logstash'][:master_node_count | int] + groups['elastic-logstash'][master_node_count | int::2]) }}"
    master_nodes: "{{ groups['elastic-logstash'][:master_node_count | int] }}"
    coordination_nodes: |-
      {%   set nodes=[] %}
      {%   for host in groups['kibana'] %}
      {%     set _ = nodes.insert(loop.index, ((hostvars[host]['ansible_host'] | string) + ":" + (elastic_port | string))) %}
      {%   endfor %}
      {{ nodes }}      
    zen_nodes: |-
      {%   set nodes=[] %}
      {%   for host in (groups['elastic-logstash'] | union(groups['kibana'])) %}
      {%     set _ = nodes.insert(loop.index, (hostvars[host]['ansible_host'] | string)) %}
      {%   endfor %}
      {{ nodes }}      
    elasticserch_interface_speed: |-
      {% set default_interface_fact = hostvars[inventory_hostname]['ansible_' + (elastic_data_interface | replace('-', '_'))] %}
      {% set speeds = [] %}
      {% if default_interface_fact['type'] == 'bridge' %}
      {%   for interface in default_interface_fact['interfaces'] %}
      {%     set interface_fact = hostvars[inventory_hostname]['ansible_' + (interface | replace('-', '_'))] %}
      {%     if 'speed' in interface_fact %}
      {%       set speed = (interface_fact['speed'] | default(1000)) | string %}
      {%       if speed == "-1" %}
      {%         set _ = speeds.append(1000) %}
      {%       else %}
      {%         set _ = speeds.append(speed | int) %}
      {%       endif %}
      {%       if 'module' in interface_fact %}
      {%         set _ = speeds.append((interface_fact['speed'] | default(1000)) | int) %}
      {%       else %}
      {%         set _ = speeds.append(1000) %}
      {%       endif %}
      {%     endif %}
      {%   endfor %}
      {% else %}
      {%   if ('module' in default_interface_fact) or (default_interface_fact['type'] == 'bond') %}
      {%     set speed = (default_interface_fact['speed'] | default(1000)) | string %}
      {%     if speed == "-1" %}
      {%       set _ = speeds.append(1000) %}
      {%     else %}
      {%       set _ = speeds.append(speed | int) %}
      {%     endif %}
      {%   else %}
      {%     set _ = speeds.append(1000) %}
      {%   endif %}
      {% endif %}
      {{ ((speeds | min) * 0.75) | int }}      
  tags:
    - always

# based on the assignment of roles to hosts, set per host booleans
- name: Node enablement
  set_fact:
    master_node: "{{ (inventory_hostname in master_nodes) | ternary(true, false) }}"
    data_node: "{{ (inventory_hostname in data_nodes) | ternary(true, false) }}"
  tags:
    - always

# Set a data node facts. The data nodes, in the case of elasticsearch are also
# ingest nodes.
- name: Set data nodes
  set_fact:
    elasticsearch_data_hosts: |-
      {% if inventory_hostname in data_nodes %}
      {%   set data_hosts = ['127.0.0.1:' + (elastic_port | string)] %}
      {% else %}
      {%   set nodes=[] %}
      {%   for host in data_nodes %}
      {%     set _ = nodes.insert(loop.index, ((hostvars[host]['ansible_host'] | string) + ":" + (elastic_port | string))) %}
      {%   endfor %}
      {%   set data_hosts = nodes | shuffle(seed=inventory_hostname) %}
      {% endif %}
      {{ data_hosts }}      
    logstash_data_hosts: |-
      {% if inventory_hostname in data_nodes %}
      {%   set data_hosts = ['127.0.0.1:' + (logstash_beat_input_port | string)] %}
      {% else %}
      {%   set nodes=[] %}
      {%   for host in data_nodes %}
      {%     set _ = nodes.insert(loop.index, ((hostvars[host]['ansible_host'] | string) + ":" + (logstash_beat_input_port | string))) %}
      {%   endfor %}
      {%   set data_hosts = nodes | shuffle(seed=inventory_hostname) %}
      {% endif %}
      {{ data_hosts }}      
  tags:
    - always