Config options: centralize imagebackend libvirt options (2)

The config options of the "nova.conf" section "libvirt" got
moved to the new central location "nova/conf/libvirt.py".
Subsequent patches will then move another options in libvirt section.
This is the second patch in a long-chain patchs.

Change-Id: I3e452172e366b87b373eff33c454472c6be8f1f2
Co-Authored-by: Markus Zoeller <mzoeller@de.ibm.com>
Implements: blueprint centralize-config-options-newton

nova/conf/libvirt.py

@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import itertools
+
 from oslo_config import cfg
 
 # Downtime period in milliseconds
@@ -213,14 +215,45 @@ libvirt_general_opts = [
                     'kernel (usually 1-99)')
 ]
 
+libvirt_imagebackend_opts = [
+    cfg.StrOpt('images_type',
+               default='default',
+               choices=('raw', 'qcow2', 'lvm', 'rbd', 'ploop', 'default'),
+               help='VM Images format. If default is specified, then'
+                    ' use_cow_images flag is used instead of this one.'),
+    cfg.StrOpt('images_volume_group',
+               help='LVM Volume Group that is used for VM images, when you'
+                    ' specify images_type=lvm.'),
+    cfg.BoolOpt('sparse_logical_volumes',
+                default=False,
+                help='Create sparse logical volumes (with virtualsize)'
+                     ' if this flag is set to True.'),
+    cfg.StrOpt('images_rbd_pool',
+               default='rbd',
+               help='The RADOS pool in which rbd volumes are stored'),
+    cfg.StrOpt('images_rbd_ceph_conf',
+               default='',  # default determined by librados
+               help='Path to the ceph configuration file to use'),
+    cfg.StrOpt('hw_disk_discard',
+               choices=('ignore', 'unmap'),
+               help='Discard option for nova managed disks. Need'
+                    ' Libvirt(1.0.6) Qemu1.5 (raw format) Qemu1.6(qcow2'
+                    ' format)'),
+]
+
+ALL_OPTS = list(itertools.chain(
+    libvirt_general_opts,
+    libvirt_imagebackend_opts,
+))
+
 
 def register_opts(conf):
     conf.register_group(libvirt_group)
-    conf.register_opts(libvirt_general_opts, group=libvirt_group)
+    conf.register_opts(ALL_OPTS, group=libvirt_group)
 
 
 # TODO(hieulq): if not using group name, oslo config will generate duplicate
 # config section. This need to be remove when completely move all libvirt
 # options to this place.
 def list_opts():
-    return {libvirt_group.name: libvirt_general_opts}
+    return {libvirt_group.name: ALL_OPTS}

nova/virt/images.py

@@ -42,10 +42,6 @@ def qemu_img_info(path, format=None):
     """Return an object containing the parsed output from qemu-img info."""
     # TODO(mikal): this code should not be referring to a libvirt specific
     # flag.
-    # NOTE(sirp): The config option import must go here to avoid an import
-    # cycle
-    CONF.import_opt('images_type', 'nova.virt.libvirt.imagebackend',
-                    group='libvirt')
     if not os.path.exists(path) and CONF.libvirt.images_type != 'rbd':
         raise exception.DiskNotFound(location=path)
 

nova/virt/libvirt/driver.py

@@ -119,8 +119,6 @@ uefi_logged = False
 LOG = logging.getLogger(__name__)
 
 CONF = nova.conf.CONF
-CONF.import_opt('hw_disk_discard', 'nova.virt.libvirt.imagebackend',
-                group='libvirt')
 CONF.import_opt('iscsi_use_multipath', 'nova.virt.libvirt.volume.iscsi',
                 group='libvirt')
 

nova/virt/libvirt/imagebackend.py

@@ -20,7 +20,6 @@ import functools
 import os
 import shutil
 
-from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_serialization import jsonutils
 from oslo_utils import excutils
@@ -45,34 +44,7 @@ from nova.virt.libvirt.storage import lvm
 from nova.virt.libvirt.storage import rbd_utils
 from nova.virt.libvirt import utils as libvirt_utils
 
-__imagebackend_opts = [
-    cfg.StrOpt('images_type',
-               default='default',
-               choices=('raw', 'qcow2', 'lvm', 'rbd', 'ploop', 'default'),
-               help='VM Images format. If default is specified, then'
-                    ' use_cow_images flag is used instead of this one.'),
-    cfg.StrOpt('images_volume_group',
-               help='LVM Volume Group that is used for VM images, when you'
-                    ' specify images_type=lvm.'),
-    cfg.BoolOpt('sparse_logical_volumes',
-                default=False,
-                help='Create sparse logical volumes (with virtualsize)'
-                     ' if this flag is set to True.'),
-    cfg.StrOpt('images_rbd_pool',
-               default='rbd',
-               help='The RADOS pool in which rbd volumes are stored'),
-    cfg.StrOpt('images_rbd_ceph_conf',
-               default='',  # default determined by librados
-               help='Path to the ceph configuration file to use'),
-    cfg.StrOpt('hw_disk_discard',
-               choices=('ignore', 'unmap'),
-               help='Discard option for nova managed disks. Need'
-                    ' Libvirt(1.0.6) Qemu1.5 (raw format) Qemu1.6(qcow2'
-                    ' format)'),
-        ]
-
 CONF = nova.conf.CONF
-CONF.register_opts(__imagebackend_opts, 'libvirt')
 CONF.import_opt('rbd_user', 'nova.virt.libvirt.volume.net', group='libvirt')
 CONF.import_opt('rbd_secret_uuid', 'nova.virt.libvirt.volume.net',
                 group='libvirt')

nova/virt/opts.py

@@ -12,7 +12,6 @@
 
 import itertools
 
-import nova.virt.libvirt.imagebackend
 import nova.virt.libvirt.imagecache
 import nova.virt.libvirt.storage.lvm
 import nova.virt.libvirt.utils
@@ -39,7 +38,6 @@ def list_opts():
     return [
         ('libvirt',
          itertools.chain(
-             nova.virt.libvirt.imagebackend.__imagebackend_opts,
              nova.virt.libvirt.imagecache.imagecache_opts,
              nova.virt.libvirt.storage.lvm.lvm_opts,
              nova.virt.libvirt.utils.libvirt_opts,