gistfile1.txt

---

- name: Create a docker.yml file
  hosts: "{{ hosts }}"
  gather_facts: yes
  tasks:
    - name: inventory template
      local_action: template src=docker.inv.j2 dest=./docker.inv
      

and the template:

[containers]
{% for key in hostvars %}
{{ key }} ansible_host={{ hostvars[key]['ansible_default_ipv4']['address'] }}
{% endfor %}
~