rbd: add var for inuse and enable setting secret

This patch refactors a variable to determine if we RBD is in
use (either directly or via cinder-volume).

It also uses this to make sure to always set rbd_user and the
rbd_secret_uuid both are set so booting from Cinder with local
storage works.

Change-Id: I052f50cd527ea222e74fdc3684613499f2b55d8e

defaults/main.yml

@@ -393,6 +393,9 @@ nova_ceph_client_uuid: 517a4663-3927-44bc-9ea7-4a90e1cd4c66
 # ceph be deployed on the nova compute hosts to enable volume backed instances.
 nova_cinder_rbd_inuse: False
 
+# Used to determine if we need a Ceph client
+nova_rbd_inuse: "(nova_libvirt_images_rbd_pool is defined) or (nova_cinder_rbd_inuse | bool)"
+
 ## General Nova configuration
 # If ``nova_osapi_compute_workers`` is unset the system will use half the number of available VCPUS to
 # compute the number of api workers to use.

tasks/main.yml

@@ -232,9 +232,8 @@
     openstack_service_venv_bin: "{{ nova_bin }}"
   when:
     - nova_virt_type != 'ironic'
-    - "nova_services['nova-compute']['group'] in group_names"
-    - "(nova_libvirt_images_rbd_pool is defined) or
-       (nova_cinder_rbd_inuse | bool)"
+    - nova_services['nova-compute']['group'] in group_names
+    - nova_rbd_inuse | bool
   tags:
     - ceph
 

templates/nova.conf.j2

@@ -250,10 +250,12 @@ cpu_model_extra_flags = {{ nova_cpu_model_extra_flags | join(',') }}
 {% endif %}
 {% endif %}
 
-{% if nova_libvirt_images_rbd_pool is defined %}
+{% if nova_rbd_inuse %}
 # ceph rbd support
 rbd_user = {{ nova_ceph_client }}
 rbd_secret_uuid = {{ nova_ceph_client_uuid }}
+{% endif %}
+{% if nova_libvirt_images_rbd_pool is defined %}
 images_type = rbd
 images_rbd_pool = {{ nova_libvirt_images_rbd_pool }}
 images_rbd_ceph_conf = /etc/ceph/ceph.conf