Fix seed VM provisioning on a remote seed hypervisor

The seed VM will fail to provision if the Ansible control host and the
seed hypervisor are not the same hosts.

This is because Kayobe creates the seed-vm-user-data file on the
seed-hypervisor host. It then invokes the jriguera.configdrive role
which uses a copy task without remote_src, which fails to find the
source file locally on the Ansible control host.

Instead we create a local temporary file for seed VM user data.

Change-Id: Iabbe4c624b9ad02bb82c323070f99c16e5822966
Story: 2007530
Task: 39338

ansible/seed-vm-provision.yml

@@ -3,7 +3,6 @@
   hosts: seed-hypervisor
   vars:
     seed_host: "{{ groups['seed'][0] }}"
-    seed_user_data_path: "{{ image_cache_path }}/seed-vm-user-data"
   pre_tasks:
     - name: Verify the seed host exists in the Ansible inventory
       fail:
@@ -20,6 +19,12 @@
         group: "{{ ansible_user_gid }}"
       become: True
 
+    - name: Create a temporary user data file locally
+      tempfile:
+        state: file
+      register: seed_user_data_file
+      delegate_to: localhost
+
     # The user data script is used to bring up the network interfaces that will
     # be configured by metadata in the configdrive. For some reason resolv.conf
     # gets configured with 660 permissions, so fix that here also.
@@ -34,7 +39,8 @@
           {% endfor %}
           # Fix permissions of resolv.conf.
           chmod 644 /etc/resolv.conf
-        dest: "{{ seed_user_data_path }}"
+        dest: "{{ seed_user_data_file.path }}"
+      delegate_to: localhost
 
   roles:
     - role: jriguera.configdrive
@@ -55,7 +61,7 @@
         {{ hostvars[seed_host].network_interfaces |
            map('net_configdrive_network_device', seed_host) |
            list }}
-      configdrive_config_user_data_path: "{{ seed_user_data_path }}"
+      configdrive_config_user_data_path: "{{ seed_user_data_file.path }}"
 
   tasks:
     - name: Set a fact containing the configdrive image path
@@ -73,9 +79,16 @@
         path: "{{ item }}"
         state: absent
       with_items:
-        - "{{ seed_user_data_path }}"
         - "{{ image_cache_path }}/{{ seed_host | to_uuid }}.gz"
 
+    - name: Ensure unnecessary local files are removed
+      file:
+        path: "{{ item }}"
+        state: absent
+      with_items:
+        - "{{ seed_user_data_file.path }}"
+      delegate_to: localhost
+
 - name: Ensure that the seed VM is provisioned
   hosts: seed-hypervisor
   vars:

releasenotes/notes/fix-remote-seed-vm-provisioning-faa8de569ca6bc89.yaml

@@ -0,0 +1,7 @@
+---
+issues:
+  - |
+    Fixes an issue where provisioning a seed VM would fail when the Ansible
+    control host and the seed hypervisor are different hosts. `See story
+    2007530 <https://storyboard.openstack.org/#!/story/2007530>`_ for more
+    details.