blueprint lvm-disk-images

Add ability to use LVM volumes for VM disks.

Implements LVM disks support for libvirt driver.

VM disks will be stored on LVM volumes in volume group
 specified by `libvirt_images_volume_group` option.
 Another option `libvirt_local_images_type` specify which storage
 type will be used. Supported values are `raw`, `lvm`, `qcow2`,
 `default`. If `libvirt_local_images_type` = `default`, usual
 logic with `use_cow_images` flag is used.
Boolean option `libvirt_sparse_logical_volumes` controls which type
 of logical volumes will be created (sparsed with virtualsize or
 usual logical volumes with full space allocation). Default value
 for this option is `False`.
Commit introduce three classes: `Raw`, `Qcow2` and `Lvm`. They contain
 image creation logic, that was stored in
 `LibvirtConnection._cache_image` and `libvirt_info` methods,
 that produce right `LibvirtGuestConfigDisk` configurations for
 libvirt. `Backend` class choose which image type to use.

Change-Id: I0d01cb7d2fd67de2565b8d45d34f7846ad4112c2

Author: Boris Filippov

Authors

@@ -23,6 +23,7 @@ Asbjørn Sannes <asbjorn.sannes@interhost.no>
 Ben McGraw <ben@pistoncloud.com>
 Ben Swartzlander <bswartz@netapp.com>
 Bilal Akhtar <bilalakhtar@ubuntu.com>
+Boris Filippov <bfilippov@griddynamics.com>
 Brad Hall <brad@nicira.com>
 Brad McConnell <bmcconne@rackspace.com>
 Brendan Maguire <B_Maguire@Dell.com>

nova/rootwrap/compute.py

@@ -188,4 +188,13 @@
     # nova/virt/libvirt/connection.py:
     filters.ReadFileFilter("/etc/iscsi/initiatorname.iscsi"),
 
+    # nova/virt/libvirt/connection.py:
+    filters.CommandFilter("/sbin/lvremove", "root"),
+
+    # nova/virt/libvirt/utils.py:
+    filters.CommandFilter("/sbin/lvcreate", "root"),
+
+    # nova/virt/libvirt/utils.py:
+    filters.CommandFilter("/sbin/vgs", "root")
+
     ]

nova/tests/fake_imagebackend.py

@@ -0,0 +1,48 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2012 Grid Dynamics
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import os
+
+from nova.virt.libvirt import config
+from nova.virt.libvirt import imagebackend
+
+
+class Backend(object):
+    def __init__(self, use_cow):
+        pass
+
+    def image(self, instance, name, suffix='', image_type=''):
+        class FakeImage(imagebackend.Image):
+            def __init__(self, instance, name, suffix=''):
+                self.path = os.path.join(instance, name + suffix)
+
+            def create_image(self, prepare_template, base,
+                              size, *args, **kwargs):
+                pass
+
+            def cache(self, fn, fname, size=None, *args, **kwargs):
+                pass
+
+            def libvirt_info(self, device_type):
+                info = config.LibvirtConfigGuestDisk()
+                info.source_type = 'file'
+                info.source_device = device_type
+                info.driver_format = 'raw'
+                info.source_path = self.path
+                return info
+
+        return FakeImage(instance, name, suffix)

nova/tests/fake_libvirt_utils.py

@@ -50,6 +50,22 @@ def mkfs(fs, path):
     pass
 
 
+def resize2fs(path):
+    pass
+
+
+def create_lvm_image(vg, lv, size, sparse=False):
+    pass
+
+
+def volume_group_free_space(vg):
+    pass
+
+
+def remove_logical_volumes(*paths):
+    pass
+
+
 def ensure_tree(path):
     pass