---
- name: gather public_keys
  hosts:
    frontal
  tasks:
    - block:
        - shell: 'ssh-keyscan -t ecdsa -H {{ hostvars[item].inventory_hostname }},{{ hostvars[item].inventory_hostname_short }}'
          args:
            creates: 'host_vars/{{ hostvars[item].inventory_hostname }}'
          register: ssh_keyscan
          with_items: "{{groups['all']}}"

        - copy:
            content: "---\nknown_hosts: \n{% for line in item.stdout_lines %}  - '{{ line }}'\n{% endfor %}"
            dest: 'host_vars/{{ hostvars[item.item].inventory_hostname }}'
            force: no
          loop: "{{ ssh_keyscan.results }}"
          loop_control:
            label: "{{ item.item }} keys"
          when: item.stdout_lines | length > 0