roles/orchestrate-devstack/tasks/main.yaml

- name: Run devstack on the controller
  include_role:
    name: run-devstack
  when: inventory_hostname == 'controller'

- name: Setup devstack on sub-nodes
  block:

  - name: Sync CA data to subnodes (when any)
    # Only do this if the tls-proxy service is defined and enabled
    include_role:
      name: sync-devstack-data
    when: devstack_services['tls-proxy']|default(false)

  - name: Run devstack on the sub-nodes
    include_role:
      name: run-devstack
    when: inventory_hostname in groups['subnode']

  - name: Discover hosts
    # Discovers compute nodes (subnodes) and maps them to cells. Only run
    # on the controller node.
    # NOTE(mriedem): We want to remove this if/when nova supports
    # auto-registration of computes with cells, but that's not happening in
    # Ocata.
    # NOTE(andreaf) This is taken (NOTE included) from the discover_hosts
    # function in devstack gate. Since this is now in devstack, which is
    # branched, we know that the discover_hosts tool exists.
    become: true
    become_user: stack
    shell: ./tools/discover_hosts.sh
    args:
      chdir: "{{ devstack_base_dir }}/devstack"
    when: inventory_hostname == 'controller'

  when:
    - '"controller" in hostvars'
    - '"subnode" in groups'