Merge "Add support for LXC volumes."

2 files changed, 78 insertions, 2 deletions

diff --git a/nova/virt/disk/api.py b/nova/virt/disk/api.py
index fd0eec79d..f1f60414b 100644
--- a/nova/virt/disk/api.py
+++ b/nova/virt/disk/api.py
@@ -106,6 +106,26 @@ def extend(image, size):
     utils.execute('resize2fs', image, check_exit_code=False)
 
 
+def bind(src, target, instance_name):
+    """Bind device to a filesytem"""
+    if src:
+        utils.execute('touch', target, run_as_root=True)
+        utils.execute('mount', '-o', 'bind', src, target,
+                run_as_root=True)
+        s = os.stat(src)
+        cgroup_info = "c %s:%s rwm" % (os.major(s.st_rdev),
+                                       os.minor(s.st_rdev))
+        cgroups_path = \
+            "/sys/fs/cgroup/devices/sysdefault/libvirt/lxc/%s/devices.allow" \
+            % instance_name
+        utils.execute('echo', '>', cgroup_info, cgroups_path, run_as_root=True)
+
+
+def unbind(target):
+    if target:
+        utils.execute('umount', target, run_as_root=True)
+
+
 class _DiskImage(object):
     """Provide operations on a disk image file."""
 
diff --git a/nova/virt/libvirt/connection.py b/nova/virt/libvirt/connection.py
index adf7aa295..efd972b4b 100644
--- a/nova/virt/libvirt/connection.py
+++ b/nova/virt/libvirt/connection.py
@@ -453,7 +453,11 @@ class LibvirtConnection(driver.ComputeDriver):
         xml = self.volume_driver_method('connect_volume',
                                         connection_info,
                                         mount_device)
-        virt_dom.attachDevice(xml)
+
+        if FLAGS.libvirt_type == 'lxc':
+            self._attach_lxc_volume(xml, virt_dom, instance_name)
+        else:
+            virt_dom.attachDevice(xml)
 
     @staticmethod
     def _get_disk_xml(xml, device):
@@ -480,13 +484,65 @@ class LibvirtConnection(driver.ComputeDriver):
             xml = self._get_disk_xml(virt_dom.XMLDesc(0), mount_device)
             if not xml:
                 raise exception.DiskNotFound(location=mount_device)
-            virt_dom.detachDevice(xml)
+            if FLAGS.libvirt_type == 'lxc':
+                self._detach_lxc_volume(xml, vort_dom, instance_name)
+            else:
+                virt_dom.detachDevice(xml)
         finally:
             self.volume_driver_method('disconnect_volume',
                                       connection_info,
                                       mount_device)
 
     @exception.wrap_exception()
+    def _attach_lxc_volume(self, xml, virt_dom, instance_name):
+        LOG.info(_('attaching LXC block device'))
+
+        lxc_container_root = self.get_lxc_container_root(virt_dom)
+        lxc_host_volume = self.get_lxc_host_device(xml)
+        lxc_container_device = self.get_lxc_container_target(xml)
+        lxc_container_target = "%s/%s" % (lxc_container_root,
+                                          lxc_container_device)
+
+        if lxc_container_target:
+            disk.bind(lxc_host_volume, lxc_container_target, instance_name)
+
+    @exception.wrap_exception()
+    def _detach_lxc_volume(self, xml, virt_dom, instance_name):
+        LOG.info(_('detaching LXC block device'))
+
+        lxc_container_root = self.get_lxc_container_root(virt_dom)
+        lxc_host_volume = self.get_lxc_host_device(xml)
+        lxc_container_device = self.get_lxc_container_target(xml)
+        lxc_container_target = "%s/%s" % (lxc_container_root,
+                                          lxc_container_device)
+
+        if lxc_container_target:
+            disk.unbind(lxc_container_target)
+
+    @staticmethod
+    def get_lxc_container_root(virt_dom):
+        xml = virt_dom.XMLDesc(0)
+        doc = ElementTree.fromstring(xml)
+        filesystem_block = doc.findall('./devices/filesystem')
+        for cnt, filesystem_nodes in enumerate(filesystem_block):
+            return filesystem_nodes[cnt].get('dir')
+
+    @staticmethod
+    def get_lxc_host_device(xml):
+        dom = minidom.parseString(xml)
+
+        for device in dom.getElementsByTagName('source'):
+            return device.getAttribute('dev')
+
+    @staticmethod
+    def get_lxc_container_target(xml):
+        dom = minidom.parseString(xml)
+
+        for device in dom.getElementsByTagName('target'):
+            filesystem = device.getAttribute('dev')
+            return 'dev/%s' % filesystem
+
+    @exception.wrap_exception()
     def snapshot(self, context, instance, image_href):
         """Create snapshot from a running VM instance.