service_discovery.yml

---
- name: Get service nodes from Undercloud
  shell: |
      source ~/{{ install.overcloud.stack }}rc
      {{ service_map[service].command }}
  register: uc_service_info
  tags: skip_ansible_lint
  when: service_map[service].command_execution == "undercloud"

- name: Discover service at Overcloud Nodes
  ignore_errors: yes
  shell: "{{ service_map[service].command }}"
  register: oc_service_info
  delegate_to: "{{ item }}"
  with_items: "{{ groups.overcloud_nodes|default([])|difference(groups.unused|default([])) }}"
  tags: skip_ansible_lint
  when: service_map[service].command_execution == "overcloud_nodes"

- name: Add hosts from Undercloud discovery to inventory
  add_host:
      name: "{{ host }}"
      groups: "{{ hostvars[host].group_names + [ service_map[service].group ] }}"
  with_items: "{{ uc_service_info.stdout.split('\n') }}"
  vars:
      host: "{{ item }}"
  tags: skip_ansible_lint
  when: service_map[service].command_execution == "undercloud"

- name: Add hosts from Overcloud discovery to inventory
  add_host:
      name: "{{ host }}"
      groups: "{{ hostvars[host].group_names + [ service_map[service].group ] }}"
  with_items: "{{ oc_service_info.results }}"
  vars:
      host: "{{ item.item }}"
  tags: skip_ansible_lint
  when:
      - service_map[service].command_execution == "overcloud_nodes"
      - item.rc == 0