---
- name: Check node state.
  register: node_state
  shell: "docker info --format '{{ '{{' }}.Swarm.LocalNodeState{{ '}}' }}'"
  ignore_errors: true

- name: Add worker to swarm.
  register: join_cmd
  shell: >
    docker swarm join
    --token {{ hostvars.admin.worker_token }}
    {{ hostvars.admin.ansible_host }}:2377
  # 0 means it was successfully added, 1 means it's already in the swarm.
  failed_when: join_cmd.rc != 0
  changed_when: join_cmd.rc == 0
  when: node_state.stdout not in [ 'active', 'locked', 'error' ]