Implement nova direct RBD image retrieve

When nova don't use rbd images (ie local storage) it still might be good
idea to use direct connection to rbd to get images rather then
connect through HTTP.

Change-Id: I4f2d7cf54e07376c7a25d45093f5d83be5422234

defaults/main.yml

@@ -365,12 +365,17 @@ nova_nfs_client: []
 # Enble and define nova_libvirt_images_rbd_pool to use rbd as nova backend
 #nova_libvirt_images_rbd_pool: vms
 nova_libvirt_images_rbd_pool: ''
-nova_ceph_client: '{{ cinder_ceph_client }}'
+nova_ceph_client: "{{ cinder_ceph_client }}"
 
 # Enabled upstream if RBD is in use on cinder backends, which requires that
 # ceph be deployed on the nova compute hosts to enable volume backed instances.
 nova_cinder_rbd_inuse: False
 
+# Enable compute nodes to retrieve images from RBD directly rather then through
+# HTTP if images_type is NOT set to RBD. Must be False if nova images stored in RBD.
+nova_glance_rbd_inuse: False
+nova_glance_images_rbd_pool: "{{ glance_rbd_store_pool | default('images') }}"
+
 # Used to determine if we need a Ceph client
 nova_rbd_inuse: "{{ (nova_libvirt_images_rbd_pool | length > 0) or (nova_cinder_rbd_inuse | bool) }}"
 

releasenotes/notes/nova_glance_rbd-ab6e9b0f5dd7b9ec.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    New variables ``nova_glance_rbd_inuse`` and ``nova_glance_images_rbd_pool`` have
+    been implemented that allows deployer to easily configure nova to retrieve glance
+    images from RBD directly, if nova uses local storage for ephemeral drives.

tasks/main.yml

@@ -270,7 +270,7 @@
   when:
     - nova_virt_type != 'ironic'
     - nova_services['nova-compute']['group'] in group_names
-    - nova_rbd_inuse | bool
+    - (nova_rbd_inuse | bool) or (nova_glance_rbd_inuse | bool)
   tags:
     - ceph
 

templates/nova.conf.j2

@@ -133,6 +133,11 @@ enabled = False
 # Glance
 [glance]
 insecure = {{ keystone_service_internaluri_insecure | bool }}
+{% if nova_glance_rbd_inuse | bool %}
+rbd_user = {{ nova_ceph_client }}
+rbd_pool = {{ nova_glance_images_rbd_pool }}
+rbd_ceph_conf = /etc/ceph/ceph.conf
+{% endif %}
 
 # Neutron
 [neutron]