ansible-role-ssh_host_key/tasks/fetch.yml

---

- name: fetch ssh host key
  command:
    cat "{{ root_target_directory | default("") }}/etc/ssh/ssh_host_ed25519_key.pub"
  register: _ssh_host_key_cat_result
  changed_when: false

- name: set fetched ssh_host_key_ed25519_public
  set_fact:
    ssh_host_key_ed25519_public: "{{ _ssh_host_key_cat_result.stdout.split()[1] }}"
  changed_when: ssh_host_key_ed25519_public != _ssh_host_key_cat_result.stdout.split()[1]