Add Ansible group variables file for seed Ansible SSH host

We currently use a libvirt network with dynamic IP address allocation for the
seed VM. After creation of the seed, determine it's IP address and update the
inventory to allow access to it.

ansible/seed-vm.yml

@@ -75,3 +75,34 @@
       libvirt_vm_interfaces: "{{ seed_hostvars.seed_vm_interfaces }}"
       libvirt_vm_image_cache_path: "{{ image_cache_path }}"
       become: True
+
+  tasks:
+    - name: Check the seed VM's IP address
+      shell: virsh domifaddr {{ seed_vm_name }} | awk 'NR > 2 { print $4 }'
+      register: ifaddr_result
+      changed_when: False
+      become: True
+      until: "{{ ifaddr_result | failed or ifaddr_result.stdout != '' }}"
+      retries: 60
+      delay: 1
+
+    # Generate an inventory file for the seed VM. Note that this host will not
+    # be accessible to this instance of Ansible - another process should be
+    # started.
+    - name: Ensure the inventory contains a group variables file for the seed
+      local_action:
+        module: copy
+        content: |
+          ---
+          # Do not edit this file - it is managed by Ansible and changes will be lost.
+          # Ansible inventory file for the Kayobe seed VM.
+          # This host will provide the Bifrost undercloud.
+          ansible_host: "{{ ifaddr_result.stdout_lines[0] | ipaddr('address') }}"
+        dest: "{{ kayobe_config_path }}/inventory/group_vars/seed/ansible-host"
+
+    - name: Wait for SSH access to the seed VM
+      local_action:
+        module: wait_for
+        host: "{{ ifaddr_result.stdout_lines[0] | ipaddr('address') }}"
+        port: 22
+        state: started