Merge "Add support for NFS-based virtual block devices"

2 files changed, 122 insertions, 0 deletions

diff --git a/nova/tests/test_libvirt.py b/nova/tests/test_libvirt.py
index 781a68033..b1359323b 100644
--- a/nova/tests/test_libvirt.py
+++ b/nova/tests/test_libvirt.py
@@ -56,6 +56,7 @@ from nova.virt.libvirt import firewall
 from nova.virt.libvirt import imagebackend
 from nova.virt.libvirt import utils as libvirt_utils
 from nova.virt.libvirt import volume
+from nova.virt.libvirt import volume_nfs
 from nova.volume import driver as volume_driver
 
 
@@ -326,6 +327,31 @@ class LibvirtVolumeTestCase(test.TestCase):
         libvirt_driver.disconnect_volume(connection_info, mount_device)
         connection_info = vol_driver.terminate_connection(vol, self.connr)
 
+    def test_libvirt_nfs_driver(self):
+        # NOTE(vish) exists is to make driver assume connecting worked
+        mnt_base = '/mnt'
+        self.flags(nfs_mount_point_base=mnt_base)
+
+        libvirt_driver = volume_nfs.NfsVolumeDriver(self.fake_conn)
+        export_string = '192.168.1.1:/nfs/share1'
+        name = 'volume-00001'
+        export_mnt_base = os.path.join(mnt_base,
+                libvirt_driver.get_hash_str(export_string))
+        file_path = os.path.join(export_mnt_base, name)
+
+        connection_info = {'data': {'export': export_string, 'name': name}}
+        mount_device = "vde"
+        conf = libvirt_driver.connect_volume(connection_info, mount_device)
+        tree = conf.format_dom()
+        self.assertEqual(tree.get('type'), 'file')
+        self.assertEqual(tree.find('./source').get('file'), file_path)
+        libvirt_driver.disconnect_volume(connection_info, mount_device)
+
+        expected_commands = [
+            ('stat', export_mnt_base),
+            ('mount', '-t', 'nfs', export_string, export_mnt_base)]
+        self.assertEqual(self.executes, expected_commands)
+
 
 class CacheConcurrencyTestCase(test.TestCase):
     def setUp(self):
diff --git a/nova/virt/libvirt/volume_nfs.py b/nova/virt/libvirt/volume_nfs.py
new file mode 100644
index 000000000..cf901b23a
--- /dev/null
+++ b/nova/virt/libvirt/volume_nfs.py
@@ -0,0 +1,96 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright (c) 2012 NetApp, Inc.
+# 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.
+
+"""Volume driver for using NFS as volumes storage. Nova compute part."""
+
+import ctypes
+import os
+
+from nova import exception
+from nova import flags
+from nova.openstack.common import cfg
+from nova.openstack.common import log as logging
+from nova import utils
+from nova.virt.libvirt import volume
+
+LOG = logging.getLogger(__name__)
+
+volume_opts = [
+    cfg.StrOpt('nfs_mount_point_base',
+               default='$state_path/mnt',
+               help='Base dir where nfs expected to be mounted on compute'),
+]
+FLAGS = flags.FLAGS
+FLAGS.register_opts(volume_opts)
+
+
+class NfsVolumeDriver(volume.LibvirtVolumeDriver):
+    """ Class implements libvirt part of volume driver for NFS
+    """
+    def __init__(self, *args, **kwargs):
+        """Create back-end to nfs and check connection"""
+        super(NfsVolumeDriver, self).__init__(*args, **kwargs)
+
+    def connect_volume(self, connection_info, mount_device):
+        """Connect the volume. Returns xml for libvirt."""
+        path = self._ensure_mounted(connection_info['data']['export'])
+        path = os.path.join(path, connection_info['data']['name'])
+        connection_info['data']['device_path'] = path
+        conf = super(NfsVolumeDriver, self).connect_volume(connection_info,
+                                                           mount_device)
+        conf.source_type = 'file'
+        return conf
+
+    def disconnect_volume(self, connection_info, mount_device):
+        """Disconnect the volume"""
+        pass
+
+    def _ensure_mounted(self, nfs_export):
+        """
+        @type nfs_export: string
+        """
+        mount_path = os.path.join(FLAGS.nfs_mount_point_base,
+                                  self.get_hash_str(nfs_export))
+        self._mount_nfs(mount_path, nfs_export, ensure=True)
+        return mount_path
+
+    def _mount_nfs(self, mount_path, nfs_share, ensure=False):
+        """Mount nfs export to mount path"""
+        if not self._path_exists(mount_path):
+            utils.execute('mkdir', '-p', mount_path)
+
+        try:
+            utils.execute('mount', '-t', 'nfs', nfs_share, mount_path,
+                          run_as_root=True)
+        except exception.ProcessExecutionError as exc:
+            if ensure and 'already mounted' in exc.message:
+                LOG.warn(_("%s is already mounted"), nfs_share)
+            else:
+                raise
+
+    @staticmethod
+    def get_hash_str(base_str):
+        """returns string that represents hash of base_str (in a hex format)"""
+        return str(ctypes.c_uint64(hash(base_str)).value)
+
+    @staticmethod
+    def _path_exists(path):
+        """Check path """
+        try:
+            return utils.execute('stat', path, run_as_root=True)
+        except exception.ProcessExecutionError:
+            return False