ansible-role-ssh-config/tasks/main.yml

- blockinfile:
    dest: /etc/ssh/ssh_config
    marker: '# ANSIBLE SSH CONFIG {mark}'
    block: |-
      {% for host in ssh_config_hosts %}
      {% set host_config = ssh_config_hosts[host] %}
      Host {{host}}
      {% if host_config.hostname is defined %}
          HostName {{host_config.hostname}} 
      {% endif %}
      {% endfor %}
  become: yes