return retdic
-def _GatherBlockDevs(instance):
+def _SymlinkBlockDev(instance_name, device_path, device_name):
+ """Set up symlinks to a instance's block device.
+
+ This is an auxiliary function run when an instance is start (on the primary
+ node) or when an instance is migrated (on the target node).
+
+ Args:
+ instance_name: the name of the target instance
+ device_path: path of the physical block device, on the node
+ device_name: 'virtual' name of the device
+
+ Returns:
+ absolute path to the disk's symlink
+
+ """
+ link_basename = "%s-%s" % (instance_name, device_name)
+ link_name = os.path.join(constants.DISK_LINKS_DIR, link_basename)
+ try:
+ os.symlink(device_path, link_name)
+ except OSError, e:
+ if e.errno == errno.EEXIST:
+ if (not os.path.islink(link_name) or
+ os.readlink(link_name) != device_path):
+ os.remove(link_name)
+ os.symlink(device_path, link_name)
+ else:
+ raise
+
+ return link_name
+
+
+def _GatherAndLinkBlockDevs(instance):
"""Set up an instance's block device(s).
This is run on the primary node at instance startup. The block
@type instance: L{objects.Instance}
@param instance: the instance whose disks we shoul assemble
- @rtype: list of L{bdev.BlockDev}
- @return: list of the block devices
+ @rtype: list
+ @return: list of (disk_object, device_path)
"""
block_devices = []
- for disk in instance.disks:
+ for idx, disk in enumerate(instance.disks):
device = _RecursiveFindBD(disk)
if device is None:
raise errors.BlockDeviceError("Block device '%s' is not set up." %
str(disk))
device.Open()
- block_devices.append((disk, device))
+ try:
+ link_name = _SymlinkBlockDev(instance.name, device.dev_path,
+ "disk%d" % idx)
+ except OSError, e:
+ raise errors.BlockDeviceError("Cannot create block device symlink: %s" %
+ e.strerror)
+
+ block_devices.append((disk, link_name))
+
return block_devices
if instance.name in running_instances:
return True
- block_devices = _GatherBlockDevs(instance)
+ block_devices = _GatherAndLinkBlockDevs(instance)
hyper = hypervisor.GetHypervisor(instance.hypervisor)
try: