Scan host for public keys then add keys to knows_hosts (ssh)

scan_add_pub_key.yml

# path default of known_hosts module is home of the user running the playbook, i.e. $HOME/.ssh/known_hosts

- name: find public key for stash
  command: ssh-keyscan "{{ domain }}"
  register: pub_key

- name: add public key for stash to known_hosts
  known_hosts:
    name: "{{ domain }}"
    key: "{{ pub_key.stdout }}"
    state: "present"