Move dib image output to /opt

In some clouds we don't have enough space on / to store a raw image,
so tell dib to write the image output to /opt.

Change-Id: Ia3d13ed811f705a450030a2046b2cd1ffd5a22b3

playbooks/opendev-build-diskimage-base/post.yaml

@@ -17,6 +17,6 @@
             application_credential_secret: '{{ image_upload_secret.application_credential_secret }}'
             user_domain_name: rackspace_cloud_domain
         container: images-1f49951f5beb
-        filename: '{{ ansible_user_dir }}/dib-images/{{ build_diskimage_image_name }}.{{ upload_image_format }}'
+        filename: '{{ build_diskimage_image_root }}/{{ build_diskimage_image_name }}.{{ upload_image_format }}'
         name: '{{ zuul.build }}-{{ build_diskimage_image_name }}.{{ upload_image_format }}'
         delete_after: 259200

roles/image-upload-swift/tasks/main.yaml

@@ -1,7 +1,7 @@
 # Run the checksums in the background while we're uploading
 - name: Get sha256 hash
   stat:
-    path: '{{ ansible_user_dir }}/dib-images/{{ build_diskimage_image_name }}.{{ upload_image_format }}'
+    path: '{{ filename }}'
     checksum_algorithm: sha256
   async: 600
   poll: 0
@@ -9,7 +9,7 @@
 
 - name: Get md5 hash
   stat:
-    path: '{{ ansible_user_dir }}/dib-images/{{ build_diskimage_image_name }}.{{ upload_image_format }}'
+    path: '{{ filename }}'
     checksum_algorithm: md5
   async: 600
   poll: 0

zuul.d/jobs.yaml

@@ -34,6 +34,8 @@
       build_diskimage_formats:
         - qcow2
         - raw
+      # /opt/dib_tmp is an ephemeral disk if present
+      build_diskimage_image_root: "/opt/dib_tmp/dib-images"
       build_diskimage_elements: &base_elements
         - vm
         - simple-init