ansible/roles/etc_hosts/tasks/main.yml

- name: Add the hostname
  lineinfile:
    path: /etc/hosts
    insertafter: '^# Ansible'
    regexp: "{{ etc_hosts_name }}$"
    line: "{{ etc_hosts_ip }} {{ etc_hosts_name }}" 
  become: true
  notify: known_hosts
  changed_when: true
  delegate_to: localhost