+class RADOSBlockDevice(BlockDev):
+ """A RADOS Block Device (rbd).
+
+ This class implements the RADOS Block Device for the backend. You need
+ the rbd kernel driver, the RADOS Tools and a working RADOS cluster for
+ this to be functional.
+
+ """
+ def __init__(self, unique_id, children, size, params):
+ """Attaches to an rbd device.
+
+ """
+ super(RADOSBlockDevice, self).__init__(unique_id, children, size, params)
+ if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+ raise ValueError("Invalid configuration data %s" % str(unique_id))
+
+ self.driver, self.rbd_name = unique_id
+
+ self.major = self.minor = None
+ self.Attach()
+
+ @classmethod
+ def Create(cls, unique_id, children, size, params):
+ """Create a new rbd device.
+
+ Provision a new rbd volume inside a RADOS pool.
+
+ """
+ if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
+ raise errors.ProgrammerError("Invalid configuration data %s" %
+ str(unique_id))
+ rbd_pool = params[constants.LDP_POOL]
+ rbd_name = unique_id[1]
+
+ # Provision a new rbd volume (Image) inside the RADOS cluster.
+ cmd = [constants.RBD_CMD, "create", "-p", rbd_pool,
+ rbd_name, "--size", "%s" % size]
+ result = utils.RunCmd(cmd)
+ if result.failed:
+ _ThrowError("rbd creation failed (%s): %s",
+ result.fail_reason, result.output)
+
+ return RADOSBlockDevice(unique_id, children, size, params)
+
+ def Remove(self):
+ """Remove the rbd device.
+
+ """
+ rbd_pool = self.params[constants.LDP_POOL]
+ rbd_name = self.unique_id[1]
+
+ if not self.minor and not self.Attach():
+ # The rbd device doesn't exist.
+ return
+
+ # First shutdown the device (remove mappings).
+ self.Shutdown()
+
+ # Remove the actual Volume (Image) from the RADOS cluster.
+ cmd = [constants.RBD_CMD, "rm", "-p", rbd_pool, rbd_name]
+ result = utils.RunCmd(cmd)
+ if result.failed:
+ _ThrowError("Can't remove Volume from cluster with rbd rm: %s - %s",
+ result.fail_reason, result.output)
+
+ def Rename(self, new_id):
+ """Rename this device.
+
+ """
+ pass
+
+ def Attach(self):
+ """Attach to an existing rbd device.
+
+ This method maps the rbd volume that matches our name with
+ an rbd device and then attaches to this device.
+
+ """
+ self.attached = False
+
+ # Map the rbd volume to a block device under /dev
+ self.dev_path = self._MapVolumeToBlockdev(self.unique_id)
+
+ try:
+ st = os.stat(self.dev_path)
+ except OSError, err:
+ logging.error("Error stat()'ing %s: %s", self.dev_path, str(err))
+ return False
+
+ if not stat.S_ISBLK(st.st_mode):
+ logging.error("%s is not a block device", self.dev_path)
+ return False
+
+ self.major = os.major(st.st_rdev)
+ self.minor = os.minor(st.st_rdev)
+ self.attached = True
+
+ return True
+
+ def _MapVolumeToBlockdev(self, unique_id):
+ """Maps existing rbd volumes to block devices.
+
+ This method should be idempotent if the mapping already exists.
+
+ @rtype: string
+ @return: the block device path that corresponds to the volume
+
+ """
+ pool = self.params[constants.LDP_POOL]
+ name = unique_id[1]
+
+ # Check if the mapping already exists.
+ showmap_cmd = [constants.RBD_CMD, "showmapped", "-p", pool]
+ result = utils.RunCmd(showmap_cmd)
+ if result.failed:
+ _ThrowError("rbd showmapped failed (%s): %s",
+ result.fail_reason, result.output)
+
+ rbd_dev = self._ParseRbdShowmappedOutput(result.output, name)
+
+ if rbd_dev:
+ # The mapping exists. Return it.
+ return rbd_dev
+
+ # The mapping doesn't exist. Create it.
+ map_cmd = [constants.RBD_CMD, "map", "-p", pool, name]
+ result = utils.RunCmd(map_cmd)
+ if result.failed:
+ _ThrowError("rbd map failed (%s): %s",
+ result.fail_reason, result.output)
+
+ # Find the corresponding rbd device.
+ showmap_cmd = [constants.RBD_CMD, "showmapped", "-p", pool]
+ result = utils.RunCmd(showmap_cmd)
+ if result.failed:
+ _ThrowError("rbd map succeeded, but showmapped failed (%s): %s",
+ result.fail_reason, result.output)
+
+ rbd_dev = self._ParseRbdShowmappedOutput(result.output, name)
+
+ if not rbd_dev:
+ _ThrowError("rbd map succeeded, but could not find the rbd block"
+ " device in output of showmapped, for volume: %s", name)
+
+ # The device was successfully mapped. Return it.
+ return rbd_dev
+
+ @staticmethod
+ def _ParseRbdShowmappedOutput(output, volume_name):
+ """Parse the output of `rbd showmapped'.
+
+ This method parses the output of `rbd showmapped' and returns
+ the rbd block device path (e.g. /dev/rbd0) that matches the
+ given rbd volume.
+
+ @type output: string
+ @param output: the whole output of `rbd showmapped'
+ @type volume_name: string
+ @param volume_name: the name of the volume whose device we search for
+ @rtype: string or None
+ @return: block device path if the volume is mapped, else None
+
+ """
+ allfields = 5
+ volumefield = 2
+ devicefield = 4
+
+ field_sep = "\t"
+
+ lines = output.splitlines()
+ splitted_lines = map(lambda l: l.split(field_sep), lines)
+
+ # Check empty output.
+ if not splitted_lines:
+ _ThrowError("rbd showmapped returned empty output")
+
+ # Check showmapped header line, to determine number of fields.
+ field_cnt = len(splitted_lines[0])
+ if field_cnt != allfields:
+ _ThrowError("Cannot parse rbd showmapped output because its format"
+ " seems to have changed; expected %s fields, found %s",
+ allfields, field_cnt)
+
+ matched_lines = \
+ filter(lambda l: len(l) == allfields and l[volumefield] == volume_name,
+ splitted_lines)
+
+ if len(matched_lines) > 1:
+ _ThrowError("The rbd volume %s is mapped more than once."
+ " This shouldn't happen, try to unmap the extra"
+ " devices manually.", volume_name)
+
+ if matched_lines:
+ # rbd block device found. Return it.
+ rbd_dev = matched_lines[0][devicefield]
+ return rbd_dev
+
+ # The given volume is not mapped.
+ return None
+
+ def Assemble(self):
+ """Assemble the device.
+
+ """
+ pass
+
+ def Shutdown(self):
+ """Shutdown the device.
+
+ """
+ if not self.minor and not self.Attach():
+ # The rbd device doesn't exist.
+ return
+
+ # Unmap the block device from the Volume.
+ self._UnmapVolumeFromBlockdev(self.unique_id)
+
+ self.minor = None
+ self.dev_path = None
+
+ def _UnmapVolumeFromBlockdev(self, unique_id):
+ """Unmaps the rbd device from the Volume it is mapped.
+
+ Unmaps the rbd device from the Volume it was previously mapped to.
+ This method should be idempotent if the Volume isn't mapped.
+
+ """
+ pool = self.params[constants.LDP_POOL]
+ name = unique_id[1]
+
+ # Check if the mapping already exists.
+ showmap_cmd = [constants.RBD_CMD, "showmapped", "-p", pool]
+ result = utils.RunCmd(showmap_cmd)
+ if result.failed:
+ _ThrowError("rbd showmapped failed [during unmap](%s): %s",
+ result.fail_reason, result.output)
+
+ rbd_dev = self._ParseRbdShowmappedOutput(result.output, name)
+
+ if rbd_dev:
+ # The mapping exists. Unmap the rbd device.
+ unmap_cmd = [constants.RBD_CMD, "unmap", "%s" % rbd_dev]
+ result = utils.RunCmd(unmap_cmd)
+ if result.failed:
+ _ThrowError("rbd unmap failed (%s): %s",
+ result.fail_reason, result.output)
+
+ def Open(self, force=False):
+ """Make the device ready for I/O.
+
+ """
+ pass
+
+ def Close(self):
+ """Notifies that the device will no longer be used for I/O.
+
+ """
+ pass
+
+ def Grow(self, amount, dryrun):
+ """Grow the Volume.
+
+ @type amount: integer
+ @param amount: the amount (in mebibytes) to grow with
+ @type dryrun: boolean
+ @param dryrun: whether to execute the operation in simulation mode
+ only, without actually increasing the size
+
+ """
+ if not self.Attach():
+ _ThrowError("Can't attach to rbd device during Grow()")
+
+ if dryrun:
+ # the rbd tool does not support dry runs of resize operations.
+ # Since rbd volumes are thinly provisioned, we assume
+ # there is always enough free space for the operation.
+ return
+
+ rbd_pool = self.params[constants.LDP_POOL]
+ rbd_name = self.unique_id[1]
+ new_size = self.size + amount
+
+ # Resize the rbd volume (Image) inside the RADOS cluster.
+ cmd = [constants.RBD_CMD, "resize", "-p", rbd_pool,
+ rbd_name, "--size", "%s" % new_size]
+ result = utils.RunCmd(cmd)
+ if result.failed:
+ _ThrowError("rbd resize failed (%s): %s",
+ result.fail_reason, result.output)
+
+
projects / ganeti-local / blobdiff