Auto-detect default overcloud-full image

When the undercloud glance is switched off the image files will be
copied to /var/lib/ironic/images. This change will choose what to set
for the default image based on whether there are image files in
/var/lib/ironic/images, falling back to a glance based
'overcloud-full'.

A missing .initrd file is used to imply that the .qcow2 file is a
whole-disk image.

This is just to determine the default image, and the image can always
be specified on a per-role basis in the baremetal provisioning yaml.

Change-Id: I3b8ba4b2a0d50077fcf4628720dff9310a200e2a
Blueprint: nova-less-deploy

tripleo_ansible/playbooks/cli-overcloud-node-provision.yaml

@@ -39,6 +39,48 @@
         - baremetal_deployed_path is undefined
 
   tasks:
+
+    - name: Detect default overcloud-full image
+      block:
+        - name: stat overcloud-full.qcow2
+          stat:
+            path: /var/lib/ironic/images/overcloud-full.qcow2
+            get_checksum: true
+            checksum_algorithm: md5
+          register: overcloud_full_stat
+
+        - name: stat overcloud-full.initrd
+          stat:
+            path: /var/lib/ironic/images/overcloud-full.initrd
+            get_checksum: false
+          register: overcloud_full_initrd_stat
+
+        - name: Set file based default image
+          set_fact:
+            default_image:
+              href: file:///var/lib/ironic/images/overcloud-full.qcow2
+              checksum: "{{ overcloud_full_stat.stat.checksum }}"
+              kernel: file:///var/lib/ironic/images/overcloud-full.vmlinuz
+              ramdisk: file:///var/lib/ironic/images/overcloud-full.initrd
+          when:
+            - overcloud_full_stat.stat.exists|bool
+            - overcloud_full_initrd_stat.stat.exists|bool
+
+        - name: Set whole-disk file based default image
+          set_fact:
+            default_image:
+              href: file:///var/lib/ironic/images/overcloud-full.qcow2
+              checksum: "{{ overcloud_full_stat.stat.checksum }}"
+          when:
+            - overcloud_full_stat.stat.exists|bool
+            - not overcloud_full_initrd_stat.stat.exists|bool
+
+        - name: Set glance based default image
+          set_fact:
+            default_image:
+              href: overcloud-full
+          when: not overcloud_full_stat.stat.exists|bool
+
     - name: Expand roles
       tripleo_baremetal_expand_roles:
         baremetal_deployment: "{{ baremetal_deployment }}"
@@ -46,6 +88,7 @@
         stack_name: "{{ stack_name }}"
         ssh_public_keys: "{{ ssh_public_keys }}"
         user_name: "{{ ssh_user_name }}"
+        default_image: "{{ default_image }}"
       register: baremetal_instances
 
     - name: Find existing instances