ocp_on_osp: switch to key-based SSH and set interpreter

ocp_on_osp.yml

@@ -6,13 +6,14 @@
     - vars/shift_stack_vars.yaml
   tasks:
     - name: Add undercloud host to inventory for each cluster to be created
-      add_host:
+      ansible.builtin.add_host:
         name: "undercloud-{{ item }}"
         group: undercloud_host
         ansible_host: "{{ undercloud_host }}"
-        ansible_connection: "ssh"
+        ansible_connection: ssh
         ansible_user: "{{ undercloud_user }}"
-        ansible_ssh_pass: "{{ undercloud_password }}"
+        ansible_ssh_private_key_file: "{{ undercloud_ssh_key }}"
+        ansible_python_interpreter: "{{ undercloud_python_interpreter }}"
       with_sequence: "start=1 count={{ ocp_cluster_count }} format=%04u"
 
 - hosts: undercloud_host

vars/shift_stack_vars.yaml

@@ -14,7 +14,8 @@ ocp_cluster_count: 1
 # pass ip/hostname used for sshing into the undercloud
 undercloud_host:
 undercloud_user: stack
-undercloud_password:
+undercloud_ssh_key:
+undercloud_python_interpreter: /usr/libexec/platform-python
 
 public_net_name: public