save to home ssh_known_host keys

tasks/file.yml

@@ -3,8 +3,9 @@
 - name: write ssh_known_hosts file
   local_action: known_hosts
   args:
-    path: "{{ playbook_dir }}/ssh_known_hosts"
+    path: "{{ lookup('env','HOME') }}/.ssh/known_hosts"
     name: "{{ item }}"
     key: "{{ lookup('template','ssh_host_key.j2') }}"
   with_items: "{{play_hosts}}"
+  when: hostvars[item].ssh_host_key_ed25519_public is defined
   run_once: true