Add os_brick-based VolumeDriver for HGST connector

Even with OS-Brick being used to support different volume types in
Nova, there still needs to be a small shim layer to actually connect
to the different volume types.

This patch includes three very minor patches to enable this:

1) Because os-brick is a library and not an application, the rootwrap
for Nova needs to include the required CLI commands to attach/detach
volumes as it can't live in os-brick's repository.

2) libvirt_volume_types needs to include the new
HGST=>LibvirtHGSTVolumeDriver mapping, because os-brick doesn't
support discovery of supported types.

3) A small shim LibvirtHGSTVolumeDriver calling the os-brick library
needs to be added, again because there is no generic way presently
for os-brick to map to specific volume types in libvirtvolumetype.

Change-Id: Ie5b5e7dc6e3a1265dd139fbde240349fc10f86bf
Depends-On: I64901b1456a3989c3ee700f1da6d47f47f2734bb
Implements: blueprint add-os-brick-volume-driver-hgst-solutions

1 files changed, 53 insertions, 0 deletions

diff --git a/nova/virt/libvirt/volume/hgst.py b/nova/virt/libvirt/volume/hgst.py
new file mode 100644
index 0000000000..088a52c130
--- /dev/null
+++ b/nova/virt/libvirt/volume/hgst.py
@@ -0,0 +1,53 @@
+# Copyright 2015 HGST
+# 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.
+
+from os_brick.initiator import connector
+from oslo_config import cfg
+
+from nova import utils
+from nova.virt.libvirt.volume import volume as libvirt_volume
+
+
+CONF = cfg.CONF
+CONF.import_opt('num_iscsi_scan_tries', 'nova.virt.libvirt.volume.iscsi',
+                group='libvirt')
+
+
+class LibvirtHGSTVolumeDriver(libvirt_volume.LibvirtBaseVolumeDriver):
+    """Driver to attach HGST volumes to libvirt."""
+    def __init__(self, connection):
+        super(LibvirtHGSTVolumeDriver,
+              self).__init__(connection, is_block_dev=True)
+        self.connector = connector.InitiatorConnector.factory(
+            'HGST', utils._get_root_helper(),
+            device_scan_attempts=CONF.libvirt.num_iscsi_scan_tries)
+
+    def get_config(self, connection_info, disk_info):
+        """Returns xml for libvirt."""
+        conf = super(LibvirtHGSTVolumeDriver,
+                     self).get_config(connection_info, disk_info)
+
+        conf.source_type = "block"
+        conf.source_path = connection_info['data']['device_path']
+        return conf
+
+    def connect_volume(self, connection_info, mount_device):
+        device_info = self.connector.connect_volume(connection_info['data'])
+        connection_info['data']['device_path'] = device_info['path']
+
+    def disconnect_volume(self, connection_info, disk_dev):
+        self.connector.disconnect_volume(connection_info['data'], None)
+        super(LibvirtHGSTVolumeDriver,
+              self).disconnect_volume(connection_info, disk_dev)