/lib/bdev.py - snf-ganeti - Greek Research and Technology Network's projects

| Branch: | Tag: | Revision:

root / lib / bdev.py @ 770fe0f9

History | View | Annotate | Download (46.9 kB)

+      #
+      #
       # Copyright (C) 2006, 2007 Google Inc.
+      #
       # This program is free software; you can redistribute it and/or modify
       # it under the terms of the GNU General Public License as published by
       # the Free Software Foundation; either version 2 of the License, or
       # (at your option) any later version.
+      #
       # This program is distributed in the hope that it will be useful, but
       # WITHOUT ANY WARRANTY; without even the implied warranty of
       # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
       # General Public License for more details.
+      #
       # You should have received a copy of the GNU General Public License
       # along with this program; if not, write to the Free Software
       # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
       # 02110-1301, USA.
       """Block device abstraction"""
       import re
       import time
       import errno
       from ganeti import utils
       from ganeti import logger
       from ganeti import errors
       from ganeti import constants
       class BlockDev(object):
         """Block device abstract class.
         A block device can be in the following states:
           - not existing on the system, and by `Create()` it goes into:
           - existing but not setup/not active, and by `Assemble()` goes into:
           - active read-write and by `Open()` it goes into
           - online (=used, or ready for use)
         A device can also be online but read-only, however we are not using
         the readonly state (MD and LV have it, if needed in the future)
         and we are usually looking at this like at a stack, so it's easier
         to conceptualise the transition from not-existing to online and back
         like a linear one.
         The many different states of the device are due to the fact that we
         need to cover many device types:
           - logical volumes are created, lvchange -a y $lv, and used
           - md arrays are created or assembled and used
           - drbd devices are attached to a local disk/remote peer and made primary
         The status of the device can be examined by `GetStatus()`, which
         returns a numerical value, depending on the position in the
         transition stack of the device.
         A block device is identified by three items:
           - the /dev path of the device (dynamic)
           - a unique ID of the device (static)
           - it's major/minor pair (dynamic)
         Not all devices implement both the first two as distinct items. LVM
         logical volumes have their unique ID (the pair volume group, logical
         volume name) in a 1-to-1 relation to the dev path. For MD devices,
         the /dev path is dynamic and the unique ID is the UUID generated at
         array creation plus the slave list. For DRBD devices, the /dev path
         is again dynamic and the unique id is the pair (host1, dev1),
         (host2, dev2).
         You can get to a device in two ways:
           - creating the (real) device, which returns you
             an attached instance (lvcreate, mdadm --create)
           - attaching of a python instance to an existing (real) device
         The second point, the attachement to a device, is different
         depending on whether the device is assembled or not. At init() time,
         we search for a device with the same unique_id as us. If found,
         good. It also means that the device is already assembled. If not,
         after assembly we'll have our correct major/minor.
         """
         STATUS_UNKNOWN = 0
         STATUS_EXISTING = 1
         STATUS_STANDBY = 2
         STATUS_ONLINE = 3
         STATUS_MAP = {
           STATUS_UNKNOWN: "unknown",
           STATUS_EXISTING: "existing",
           STATUS_STANDBY: "ready for use",
           STATUS_ONLINE: "online",
+          }
         def __init__(self, unique_id, children):
           self._children = children
           self.dev_path = None
           self.unique_id = unique_id
           self.major = None
           self.minor = None
         def Assemble(self):
           """Assemble the device from its components.
           If this is a plain block device (e.g. LVM) than assemble does
           nothing, as the LVM has no children and we don't put logical
           volumes offline.
           One guarantee is that after the device has been assembled, it
           knows its major/minor numbers. This allows other devices (usually
           parents) to probe correctly for their children.
           """
           status = True
           for child in self._children:
             if not isinstance(child, BlockDev):
               raise TypeError("Invalid child passed of type '%s'" % type(child))
             if not status:
               break
             status = status and child.Assemble()
             if not status:
               break
             status = status and child.Open()
           if not status:
             for child in self._children:
               child.Shutdown()
           return status
         def Attach(self):
           """Find a device which matches our config and attach to it.
           """
           raise NotImplementedError
         def Close(self):
           """Notifies that the device will no longer be used for I/O.
           """
           raise NotImplementedError
         @classmethod
         def Create(cls, unique_id, children, size):
           """Create the device.
           If the device cannot be created, it will return None
           instead. Error messages go to the logging system.
           Note that for some devices, the unique_id is used, and for other,
           the children. The idea is that these two, taken together, are
           enough for both creation and assembly (later).
           """
           raise NotImplementedError
         def Remove(self):
           """Remove this device.
           This makes sense only for some of the device types: LV and to a
           lesser degree, md devices. Also note that if the device can't
           attach, the removal can't be completed.
           """
           raise NotImplementedError
         def GetStatus(self):
           """Return the status of the device.
           """
           raise NotImplementedError
         def Open(self, force=False):
           """Make the device ready for use.
           This makes the device ready for I/O. For now, just the DRBD
           devices need this.
           The force parameter signifies that if the device has any kind of
           --force thing, it should be used, we know what we are doing.
           """
           raise NotImplementedError
         def Shutdown(self):
           """Shut down the device, freeing its children.
           This undoes the `Assemble()` work, except for the child
           assembling; as such, the children on the device are still
           assembled after this call.
           """
           raise NotImplementedError
         def SetSyncSpeed(self, speed):
           """Adjust the sync speed of the mirror.
           In case this is not a mirroring device, this is no-op.
           """
           result = True
           if self._children:
             for child in self._children:
               result = result and child.SetSyncSpeed(speed)
           return result
         def GetSyncStatus(self):
           """Returns the sync status of the device.
           If this device is a mirroring device, this function returns the
           status of the mirror.
           Returns:
            (sync_percent, estimated_time, is_degraded)
           If sync_percent is None, it means all is ok
           If estimated_time is None, it means we can't estimate
           the time needed, otherwise it's the time left in seconds
           If is_degraded is True, it means the device is missing
           redundancy. This is usually a sign that something went wrong in
           the device setup, if sync_percent is None.
           """
           return None, None, False
         def CombinedSyncStatus(self):
           """Calculate the mirror status recursively for our children.
           The return value is the same as for `GetSyncStatus()` except the
           minimum percent and maximum time are calculated across our
           children.
           """
           min_percent, max_time, is_degraded = self.GetSyncStatus()
           if self._children:
             for child in self._children:
               c_percent, c_time, c_degraded = child.GetSyncStatus()
               if min_percent is None:
                 min_percent = c_percent
               elif c_percent is not None:
                 min_percent = min(min_percent, c_percent)
               if max_time is None:
                 max_time = c_time
               elif c_time is not None:
                 max_time = max(max_time, c_time)
               is_degraded = is_degraded or c_degraded
           return min_percent, max_time, is_degraded
         def SetInfo(self, text):
           """Update metadata with info text.
           Only supported for some device types.
           """
           for child in self._children:
             child.SetInfo(text)
         def __repr__(self):
           return ("<%s: unique_id: %s, children: %s, %s:%s, %s>" %
                   (self.__class__, self.unique_id, self._children,
                    self.major, self.minor, self.dev_path))
       class LogicalVolume(BlockDev):
         """Logical Volume block device.
         """
         def __init__(self, unique_id, children):
           """Attaches to a LV device.
           The unique_id is a tuple (vg_name, lv_name)
           """
           super(LogicalVolume, self).__init__(unique_id, children)
           if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
             raise ValueError("Invalid configuration data %s" % str(unique_id))
           self._vg_name, self._lv_name = unique_id
           self.dev_path = "/dev/%s/%s" % (self._vg_name, self._lv_name)
           self.Attach()
         @classmethod
         def Create(cls, unique_id, children, size):
           """Create a new logical volume.
           """
           if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 2:
             raise ValueError("Invalid configuration data %s" % str(unique_id))
           vg_name, lv_name = unique_id
           pvs_info = cls.GetPVInfo(vg_name)
           if not pvs_info:
             raise errors.BlockDeviceError("Can't compute PV info for vg %s" %
                                           vg_name)
           pvs_info.sort()
           pvs_info.reverse()
           pvlist = [ pv[1] for pv in pvs_info ]
           free_size = sum([ pv[0] for pv in pvs_info ])
           # The size constraint should have been checked from the master before
           # calling the create function.
           if free_size < size:
             raise errors.BlockDeviceError("Not enough free space: required %s,"
                                           " available %s" % (size, free_size))
           result = utils.RunCmd(["lvcreate", "-L%dm" % size, "-n%s" % lv_name,
                                  vg_name] + pvlist)
           if result.failed:
             raise errors.BlockDeviceError(result.fail_reason)
           return LogicalVolume(unique_id, children)
         @staticmethod
         def GetPVInfo(vg_name):
           """Get the free space info for PVs in a volume group.
           Args:
             vg_name: the volume group name
           Returns:
             list of (free_space, name) with free_space in mebibytes
           """
           command = ["pvs", "--noheadings", "--nosuffix", "--units=m",
                      "-opv_name,vg_name,pv_free,pv_attr", "--unbuffered",
                      "--separator=:"]
           result = utils.RunCmd(command)
           if result.failed:
             logger.Error("Can't get the PV information: %s" % result.fail_reason)
             return None
           data = []
           for line in result.stdout.splitlines():
             fields = line.strip().split(':')
             if len(fields) != 4:
               logger.Error("Can't parse pvs output: line '%s'" % line)
               return None
             # skip over pvs from another vg or ones which are not allocatable
             if fields[1] != vg_name or fields[3][0] != 'a':
               continue
             data.append((float(fields[2]), fields[0]))
           return data
         def Remove(self):
           """Remove this logical volume.
           """
           if not self.minor and not self.Attach():
             # the LV does not exist
             return True
           result = utils.RunCmd(["lvremove", "-f", "%s/%s" %
                                  (self._vg_name, self._lv_name)])
           if result.failed:
             logger.Error("Can't lvremove: %s" % result.fail_reason)
           return not result.failed
         def Attach(self):
           """Attach to an existing LV.
           This method will try to see if an existing and active LV exists
           which matches the our name. If so, its major/minor will be
           recorded.
           """
           result = utils.RunCmd(["lvdisplay", self.dev_path])
           if result.failed:
             logger.Error("Can't find LV %s: %s" %
                          (self.dev_path, result.fail_reason))
             return False
           match = re.compile("^ *Block device *([0-9]+):([0-9]+).*$")
           for line in result.stdout.splitlines():
             match_result = match.match(line)
             if match_result:
               self.major = int(match_result.group(1))
               self.minor = int(match_result.group(2))
               return True
           return False
         def Assemble(self):
           """Assemble the device.
           This is a no-op for the LV device type. Eventually, we could
           lvchange -ay here if we see that the LV is not active.
           """
           return True
         def Shutdown(self):
           """Shutdown the device.
           This is a no-op for the LV device type, as we don't deactivate the
           volumes on shutdown.
           """
           return True
         def GetStatus(self):
           """Return the status of the device.
           Logical volumes will can be in all four states, although we don't
           deactivate (lvchange -an) them when shutdown, so STATUS_EXISTING
           should not be seen for our devices.
           """
           result = utils.RunCmd(["lvs", "--noheadings", "-olv_attr", self.dev_path])
           if result.failed:
             logger.Error("Can't display lv: %s" % result.fail_reason)
             return self.STATUS_UNKNOWN
           out = result.stdout.strip()
           # format: type/permissions/alloc/fixed_minor/state/open
           if len(out) != 6:
             return self.STATUS_UNKNOWN
           #writable = (out[1] == "w")
           active = (out[4] == "a")
           online = (out[5] == "o")
           if online:
             retval = self.STATUS_ONLINE
           elif active:
             retval = self.STATUS_STANDBY
           else:
             retval = self.STATUS_EXISTING
           return retval
         def Open(self, force=False):
           """Make the device ready for I/O.
           This is a no-op for the LV device type.
           """
           return True
         def Close(self):
           """Notifies that the device will no longer be used for I/O.
           This is a no-op for the LV device type.
           """
           return True
         def Snapshot(self, size):
           """Create a snapshot copy of an lvm block device.
           """
           snap_name = self._lv_name + ".snap"
           # remove existing snapshot if found
           snap = LogicalVolume((self._vg_name, snap_name), None)
           snap.Remove()
           pvs_info = self.GetPVInfo(self._vg_name)
           if not pvs_info:
             raise errors.BlockDeviceError("Can't compute PV info for vg %s" %
                                           self._vg_name)
           pvs_info.sort()
           pvs_info.reverse()
           free_size, pv_name = pvs_info[0]
           if free_size < size:
             raise errors.BlockDeviceError("Not enough free space: required %s,"
                                           " available %s" % (size, free_size))
           result = utils.RunCmd(["lvcreate", "-L%dm" % size, "-s",
                                  "-n%s" % snap_name, self.dev_path])
           if result.failed:
             raise errors.BlockDeviceError("command: %s error: %s" %
                                           (result.cmd, result.fail_reason))
           return snap_name
         def SetInfo(self, text):
           """Update metadata with info text.
           """
           BlockDev.SetInfo(self, text)
           # Replace invalid characters
           text = re.sub('^[^A-Za-z0-9_+.]', '_', text)
           text = re.sub('[^-A-Za-z0-9_+.]', '_', text)
           # Only up to 128 characters are allowed
           text = text[:128]
           result = utils.RunCmd(["lvchange", "--addtag", text,
                                  self.dev_path])
           if result.failed:
             raise errors.BlockDeviceError("Command: %s error: %s" %
                                           (result.cmd, result.fail_reason))
       class MDRaid1(BlockDev):
         """raid1 device implemented via md.
         """
         def __init__(self, unique_id, children):
           super(MDRaid1, self).__init__(unique_id, children)
           self.major = 9
           self.Attach()
         def Attach(self):
           """Find an array which matches our config and attach to it.
           This tries to find a MD array which has the same UUID as our own.
           """
           minor = self._FindMDByUUID(self.unique_id)
           if minor is not None:
             self._SetFromMinor(minor)
           else:
             self.minor = None
             self.dev_path = None
           return (minor is not None)
         @staticmethod
         def _GetUsedDevs():
           """Compute the list of in-use MD devices.
           It doesn't matter if the used device have other raid level, just
           that they are in use.
           """
           mdstat = open("/proc/mdstat", "r")
           data = mdstat.readlines()
           mdstat.close()
           used_md = {}
           valid_line = re.compile("^md([0-9]+) : .*$")
           for line in data:
             match = valid_line.match(line)
             if match:
               md_no = int(match.group(1))
               used_md[md_no] = line
           return used_md
         @staticmethod
         def _GetDevInfo(minor):
           """Get info about a MD device.
           Currently only uuid is returned.
           """
           result = utils.RunCmd(["mdadm", "-D", "/dev/md%d" % minor])
           if result.failed:
             logger.Error("Can't display md: %s" % result.fail_reason)
             return None
           retval = {}
           for line in result.stdout.splitlines():
             line = line.strip()
             kv = line.split(" : ", 1)
             if kv:
               if kv[0] == "UUID":
                 retval["uuid"] = kv[1].split()[0]
               elif kv[0] == "State":
                 retval["state"] = kv[1].split(", ")
           return retval
         @staticmethod
         def _FindUnusedMinor():
           """Compute an unused MD minor.
           This code assumes that there are 256 minors only.
           """
           used_md = MDRaid1._GetUsedDevs()
           i = 0
           while i < 256:
             if i not in used_md:
               break
             i += 1
           if i == 256:
             logger.Error("Critical: Out of md minor numbers.")
             return None
           return i
         @classmethod
         def _FindMDByUUID(cls, uuid):
           """Find the minor of an MD array with a given UUID.
           """
           md_list = cls._GetUsedDevs()
           for minor in md_list:
             info = cls._GetDevInfo(minor)
             if info and info["uuid"] == uuid:
               return minor
           return None
         @staticmethod
         def _ZeroSuperblock(dev_path):
           """Zero the possible locations for an MD superblock.
           The zero-ing can't be done via ``mdadm --zero-superblock`` as that
           fails in versions 2.x with the same error code as non-writable
           device.
           The superblocks are located at (negative values are relative to
           the end of the block device):
             - -128k to end for version 0.90 superblock
             - -8k to -12k for version 1.0 superblock (included in the above)
             - 0k to 4k for version 1.1 superblock
             - 4k to 8k for version 1.2 superblock
           To cover all situations, the zero-ing will be:
             - 0k to 128k
             - -128k to end
           As such, the minimum device size must be 128k, otherwise we'll get
           I/O errors.
           Note that this function depends on the fact that one can open,
           read and write block devices normally.
           """
           overwrite_size = 128 * 1024
           empty_buf = '\0' * overwrite_size
           fd = open(dev_path, "r+")
           try:
             fd.seek(0, 0)
             p1 = fd.tell()
             fd.write(empty_buf)
             p2 = fd.tell()
             logger.Debug("Zeroed %s from %d to %d" % (dev_path, p1, p2))
             fd.seek(-overwrite_size, 2)
             p1 = fd.tell()
             fd.write(empty_buf)
             p2 = fd.tell()
             logger.Debug("Zeroed %s from %d to %d" % (dev_path, p1, p2))
           finally:
             fd.close()
         @classmethod
         def Create(cls, unique_id, children, size):
           """Create a new MD raid1 array.
           """
           if not isinstance(children, (tuple, list)):
             raise ValueError("Invalid setup data for MDRaid1 dev: %s" %
                              str(children))
           for i in children:
             if not isinstance(i, BlockDev):
               raise ValueError("Invalid member in MDRaid1 dev: %s" % type(i))
           for i in children:
             try:
               cls._ZeroSuperblock(i.dev_path)
             except EnvironmentError, err:
               logger.Error("Can't zero superblock for %s: %s" %
                            (i.dev_path, str(err)))
               return None
           minor = cls._FindUnusedMinor()
           result = utils.RunCmd(["mdadm", "--create", "/dev/md%d" % minor,
                                  "--auto=yes", "--force", "-l1",
                                  "-n%d" % len(children)] +
                                 [dev.dev_path for dev in children])
           if result.failed:
             logger.Error("Can't create md: %s: %s" % (result.fail_reason,
                                                       result.output))
             return None
           info = cls._GetDevInfo(minor)
           if not info or not "uuid" in info:
             logger.Error("Wrong information returned from mdadm -D: %s" % str(info))
             return None
           return MDRaid1(info["uuid"], children)
         def Remove(self):
           """Stub remove function for MD RAID 1 arrays.
           We don't remove the superblock right now. Mark a to do.
           """
           #TODO: maybe zero superblock on child devices?
           return self.Shutdown()
         def AddChild(self, device):
           """Add a new member to the md raid1.
           """
           if self.minor is None and not self.Attach():
             raise errors.BlockDeviceError("Can't attach to device")
           if device.dev_path is None:
             raise errors.BlockDeviceError("New child is not initialised")
           result = utils.RunCmd(["mdadm", "-a", self.dev_path, device.dev_path])
           if result.failed:
             raise errors.BlockDeviceError("Failed to add new device to array: %s" %
                                           result.output)
           new_len = len(self._children) + 1
           result = utils.RunCmd(["mdadm", "--grow", self.dev_path, "-n", new_len])
           if result.failed:
             raise errors.BlockDeviceError("Can't grow md array: %s" %
                                           result.output)
           self._children.append(device)
         def RemoveChild(self, dev_path):
           """Remove member from the md raid1.
           """
           if self.minor is None and not self.Attach():
             raise errors.BlockDeviceError("Can't attach to device")
           if len(self._children) == 1:
             raise errors.BlockDeviceError("Can't reduce member when only one"
                                           " child left")
           for device in self._children:
             if device.dev_path == dev_path:
               break
           else:
             raise errors.BlockDeviceError("Can't find child with this path")
           new_len = len(self._children) - 1
           result = utils.RunCmd(["mdadm", "-f", self.dev_path, dev_path])
           if result.failed:
             raise errors.BlockDeviceError("Failed to mark device as failed: %s" %
                                           result.output)
           # it seems here we need a short delay for MD to update its
           # superblocks
           time.sleep(0.5)
           result = utils.RunCmd(["mdadm", "-r", self.dev_path, dev_path])
           if result.failed:
             raise errors.BlockDeviceError("Failed to remove device from array:"
                                               " %s" % result.output)
           result = utils.RunCmd(["mdadm", "--grow", "--force", self.dev_path,
                                  "-n", new_len])
           if result.failed:
             raise errors.BlockDeviceError("Can't shrink md array: %s" %
                                           result.output)
           self._children.remove(device)
         def GetStatus(self):
           """Return the status of the device.
           """
           self.Attach()
           if self.minor is None:
             retval = self.STATUS_UNKNOWN
           else:
             retval = self.STATUS_ONLINE
           return retval
         def _SetFromMinor(self, minor):
           """Set our parameters based on the given minor.
           This sets our minor variable and our dev_path.
           """
           self.minor = minor
           self.dev_path = "/dev/md%d" % minor
         def Assemble(self):
           """Assemble the MD device.
           At this point we should have:
             - list of children devices
             - uuid
           """
           result = super(MDRaid1, self).Assemble()
           if not result:
             return result
           md_list = self._GetUsedDevs()
           for minor in md_list:
             info = self._GetDevInfo(minor)
             if info and info["uuid"] == self.unique_id:
               self._SetFromMinor(minor)
               logger.Info("MD array %s already started" % str(self))
               return True
           free_minor = self._FindUnusedMinor()
           result = utils.RunCmd(["mdadm", "-A", "--auto=yes", "--uuid",
                                  self.unique_id, "/dev/md%d" % free_minor] +
                                 [bdev.dev_path for bdev in self._children])
           if result.failed:
             logger.Error("Can't assemble MD array: %s: %s" %
                          (result.fail_reason, result.output))
             self.minor = None
           else:
             self.minor = free_minor
           return not result.failed
         def Shutdown(self):
           """Tear down the MD array.
           This does a 'mdadm --stop' so after this command, the array is no
           longer available.
           """
           if self.minor is None and not self.Attach():
             logger.Info("MD object not attached to a device")
             return True
           result = utils.RunCmd(["mdadm", "--stop", "/dev/md%d" % self.minor])
           if result.failed:
             logger.Error("Can't stop MD array: %s" % result.fail_reason)
             return False
           self.minor = None
           self.dev_path = None
           return True
         def SetSyncSpeed(self, kbytes):
           """Set the maximum sync speed for the MD array.
           """
           result = super(MDRaid1, self).SetSyncSpeed(kbytes)
           if self.minor is None:
             logger.Error("MD array not attached to a device")
             return False
           f = open("/sys/block/md%d/md/sync_speed_max" % self.minor, "w")
           try:
             f.write("%d" % kbytes)
           finally:
             f.close()
           f = open("/sys/block/md%d/md/sync_speed_min" % self.minor, "w")
           try:
             f.write("%d" % (kbytes/2))
           finally:
             f.close()
           return result
         def GetSyncStatus(self):
           """Returns the sync status of the device.
           Returns:
            (sync_percent, estimated_time)
           If sync_percent is None, it means all is ok
           If estimated_time is None, it means we can't esimate
           the time needed, otherwise it's the time left in seconds
           """
           if self.minor is None and not self.Attach():
             raise errors.BlockDeviceError("Can't attach to device in GetSyncStatus")
           dev_info = self._GetDevInfo(self.minor)
           is_clean = ("state" in dev_info and
                       len(dev_info["state"]) == 1 and
                       dev_info["state"][0] in ("clean", "active"))
           sys_path = "/sys/block/md%s/md/" % self.minor
           f = file(sys_path + "sync_action")
           sync_status = f.readline().strip()
           f.close()
           if sync_status == "idle":
             return None, None, not is_clean
           f = file(sys_path + "sync_completed")
           sync_completed = f.readline().strip().split(" / ")
           f.close()
           if len(sync_completed) != 2:
             return 0, None, not is_clean
           sync_done, sync_total = [float(i) for i in sync_completed]
           sync_percent = 100.0*sync_done/sync_total
           f = file(sys_path + "sync_speed")
           sync_speed_k = int(f.readline().strip())
           if sync_speed_k == 0:
             time_est = None
           else:
             time_est = (sync_total - sync_done) / 2 / sync_speed_k
           return sync_percent, time_est, not is_clean
         def Open(self, force=False):
           """Make the device ready for I/O.
           This is a no-op for the MDRaid1 device type, although we could use
           the 2.6.18's new array_state thing.
           """
           return True
         def Close(self):
           """Notifies that the device will no longer be used for I/O.
           This is a no-op for the MDRaid1 device type, but see comment for
           `Open()`.
           """
           return True
       class BaseDRBD(BlockDev):
         """Base DRBD class.
         This class contains a few bits of common functionality between the
 .7 and 8.x versions of DRBD.
         """
         _VERSION_RE = re.compile(r"^version: (\d+)\.(\d+)\.(\d+)"
                                  r" \(api:(\d+)/proto:(\d+)\)")
         _DRBD_MAJOR = 147
         _ST_UNCONFIGURED = "Unconfigured"
         _ST_WFCONNECTION = "WFConnection"
         _ST_CONNECTED = "Connected"
         @staticmethod
         def _GetProcData():
           """Return data from /proc/drbd.
           """
           stat = open("/proc/drbd", "r")
           try:
             data = stat.read().splitlines()
           finally:
             stat.close()
           if not data:
             raise errors.BlockDeviceError("Can't read any data from /proc/drbd")
           return data
         @classmethod
         def _GetVersion(cls):
           """Return the DRBD version.
           This will return a list [k_major, k_minor, k_point, api, proto].
           """
           proc_data = cls._GetProcData()
           first_line = proc_data[0].strip()
           version = cls._VERSION_RE.match(first_line)
           if not version:
             raise errors.BlockDeviceError("Can't parse DRBD version from '%s'" %
                                           first_line)
           return [int(val) for val in version.groups()]
         @staticmethod
         def _DevPath(minor):
           """Return the path to a drbd device for a given minor.
           """
           return "/dev/drbd%d" % minor
         @classmethod
         def _GetUsedDevs(cls):
           """Compute the list of used DRBD devices.
           """
           data = cls._GetProcData()
           used_devs = {}
           valid_line = re.compile("^ *([0-9]+): cs:([^ ]+).*$")
           for line in data:
             match = valid_line.match(line)
             if not match:
               continue
             minor = int(match.group(1))
             state = match.group(2)
             if state == cls._ST_UNCONFIGURED:
               continue
             used_devs[minor] = state, line
           return used_devs
       class DRBDev(BaseDRBD):
         """DRBD block device.
         This implements the local host part of the DRBD device, i.e. it
         doesn't do anything to the supposed peer. If you need a fully
         connected DRBD pair, you need to use this class on both hosts.
         The unique_id for the drbd device is the (local_ip, local_port,
         remote_ip, remote_port) tuple, and it must have two children: the
         data device and the meta_device. The meta device is checked for
         valid size and is zeroed on create.
         """
         def __init__(self, unique_id, children):
           super(DRBDev, self).__init__(unique_id, children)
           self.major = self._DRBD_MAJOR
           [kmaj, kmin, kfix, api, proto] = self._GetVersion()
           if kmaj != 0 and kmin != 7:
             raise errors.BlockDeviceError("Mismatch in DRBD kernel version and"
                                           " requested ganeti usage: kernel is"
                                           " %s.%s, ganeti wants 0.7" % (kmaj, kmin))
           if len(children) != 2:
             raise ValueError("Invalid configuration data %s" % str(children))
           if not isinstance(unique_id, (tuple, list)) or len(unique_id) != 4:
             raise ValueError("Invalid configuration data %s" % str(unique_id))
           self._lhost, self._lport, self._rhost, self._rport = unique_id
           self.Attach()
         @classmethod
         def _FindUnusedMinor(cls):
           """Find an unused DRBD device.
           """
           data = cls._GetProcData()
           valid_line = re.compile("^ *([0-9]+): cs:Unconfigured$")
           for line in data:
             match = valid_line.match(line)
             if match:
               return int(match.group(1))
           logger.Error("Error: no free drbd minors!")
           return None
         @classmethod
         def _GetDevInfo(cls, minor):
           """Get details about a given DRBD minor.
           This return, if available, the local backing device in (major,
           minor) formant and the local and remote (ip, port) information.
           """
           data = {}
           result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "show"])
           if result.failed:
             logger.Error("Can't display the drbd config: %s" % result.fail_reason)
             return data
           out = result.stdout
           if out == "Not configured\n":
             return data
           for line in out.splitlines():
             if "local_dev" not in data:
               match = re.match("^Lower device: ([0-9]+):([0-9]+) .*$", line)
               if match:
                 data["local_dev"] = (int(match.group(1)), int(match.group(2)))
                 continue
             if "meta_dev" not in data:
               match = re.match("^Meta device: (([0-9]+):([0-9]+)|internal).*$", line)
               if match:
                 if match.group(2) is not None and match.group(3) is not None:
                   # matched on the major/minor
                   data["meta_dev"] = (int(match.group(2)), int(match.group(3)))
                 else:
                   # matched on the "internal" string
                   data["meta_dev"] = match.group(1)
                   # in this case, no meta_index is in the output
                   data["meta_index"] = -1
                 continue
             if "meta_index" not in data:
               match = re.match("^Meta index: ([0-9]+).*$", line)
               if match:
                 data["meta_index"] = int(match.group(1))
                 continue
             if "local_addr" not in data:
               match = re.match("^Local address: ([0-9.]+):([0-9]+)$", line)
               if match:
                 data["local_addr"] = (match.group(1), int(match.group(2)))
                 continue
             if "remote_addr" not in data:
               match = re.match("^Remote address: ([0-9.]+):([0-9]+)$", line)
               if match:
                 data["remote_addr"] = (match.group(1), int(match.group(2)))
                 continue
           return data
         def _MatchesLocal(self, info):
           """Test if our local config matches with an existing device.
           The parameter should be as returned from `_GetDevInfo()`. This
           method tests if our local backing device is the same as the one in
           the info parameter, in effect testing if we look like the given
           device.
           """
           if not ("local_dev" in info and "meta_dev" in info and
                   "meta_index" in info):
             return False
           backend = self._children[0]
           if backend is not None:
             retval = (info["local_dev"] == (backend.major, backend.minor))
           else:
             retval = (info["local_dev"] == (0, 0))
           meta = self._children[1]
           if meta is not None:
             retval = retval and (info["meta_dev"] == (meta.major, meta.minor))
             retval = retval and (info["meta_index"] == 0)
           else:
             retval = retval and (info["meta_dev"] == "internal" and
                                  info["meta_index"] == -1)
           return retval
         def _MatchesNet(self, info):
           """Test if our network config matches with an existing device.
           The parameter should be as returned from `_GetDevInfo()`. This
           method tests if our network configuration is the same as the one
           in the info parameter, in effect testing if we look like the given
           device.
           """
           if (((self._lhost is None and not ("local_addr" in info)) and
                (self._rhost is None and not ("remote_addr" in info)))):
             return True
           if self._lhost is None:
             return False
           if not ("local_addr" in info and
                   "remote_addr" in info):
             return False
           retval = (info["local_addr"] == (self._lhost, self._lport))
           retval = (retval and
                     info["remote_addr"] == (self._rhost, self._rport))
           return retval
         @staticmethod
         def _IsValidMeta(meta_device):
           """Check if the given meta device looks like a valid one.
           This currently only check the size, which must be around
 MiB.
           """
           result = utils.RunCmd(["blockdev", "--getsize", meta_device])
           if result.failed:
             logger.Error("Failed to get device size: %s" % result.fail_reason)
             return False
           try:
             sectors = int(result.stdout)
           except ValueError:
             logger.Error("Invalid output from blockdev: '%s'" % result.stdout)
             return False
           bytes = sectors * 512
           if bytes < 128*1024*1024: # less than 128MiB
             logger.Error("Meta device too small (%.2fMib)" % (bytes/1024/1024))
             return False
           if bytes > (128+32)*1024*1024: # account for an extra (big) PE on LVM
             logger.Error("Meta device too big (%.2fMiB)" % (bytes/1024/1024))
             return False
           return True
         @classmethod
         def _AssembleLocal(cls, minor, backend, meta):
           """Configure the local part of a DRBD device.
           This is the first thing that must be done on an unconfigured DRBD
           device. And it must be done only once.
           """
           if not cls._IsValidMeta(meta):
             return False
           result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "disk",
                                  backend, meta, "0", "-e", "detach"])
           if result.failed:
             logger.Error("Can't attach local disk: %s" % result.output)
           return not result.failed
         @classmethod
         def _ShutdownLocal(cls, minor):
           """Detach from the local device.
           I/Os will continue to be served from the remote device. If we
           don't have a remote device, this operation will fail.
           """
           result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "detach"])
           if result.failed:
             logger.Error("Can't detach local device: %s" % result.output)
           return not result.failed
         @staticmethod
         def _ShutdownAll(minor):
           """Deactivate the device.
           This will, of course, fail if the device is in use.
           """
           result = utils.RunCmd(["drbdsetup", DRBDev._DevPath(minor), "down"])
           if result.failed:
             logger.Error("Can't shutdown drbd device: %s" % result.output)
           return not result.failed
         @classmethod
         def _AssembleNet(cls, minor, net_info, protocol):
           """Configure the network part of the device.
           This operation can be, in theory, done multiple times, but there
           have been cases (in lab testing) in which the network part of the
           device had become stuck and couldn't be shut down because activity
           from the new peer (also stuck) triggered a timer re-init and
           needed remote peer interface shutdown in order to clear. So please
           don't change online the net config.
           """
           lhost, lport, rhost, rport = net_info
           result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "net",
                                  "%s:%s" % (lhost, lport), "%s:%s" % (rhost, rport),
                                  protocol])
           if result.failed:
             logger.Error("Can't setup network for dbrd device: %s" %
                          result.fail_reason)
             return False
           timeout = time.time() + 10
           ok = False
           while time.time() < timeout:
             info = cls._GetDevInfo(minor)
             if not "local_addr" in info or not "remote_addr" in info:
               time.sleep(1)
               continue
             if (info["local_addr"] != (lhost, lport) or
                 info["remote_addr"] != (rhost, rport)):
               time.sleep(1)
               continue
             ok = True
             break
           if not ok:
             logger.Error("Timeout while configuring network")
             return False
           return True
         @classmethod
         def _ShutdownNet(cls, minor):
           """Disconnect from the remote peer.
           This fails if we don't have a local device.
           """
           result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "disconnect"])
           logger.Error("Can't shutdown network: %s" % result.output)
           return not result.failed
         def _SetFromMinor(self, minor):
           """Set our parameters based on the given minor.
           This sets our minor variable and our dev_path.
           """
           if minor is None:
             self.minor = self.dev_path = None
           else:
             self.minor = minor
             self.dev_path = self._DevPath(minor)
         def Assemble(self):
           """Assemble the drbd.
           Method:
             - if we have a local backing device, we bind to it by:
               - checking the list of used drbd devices
               - check if the local minor use of any of them is our own device
               - if yes, abort?
               - if not, bind
             - if we have a local/remote net info:
               - redo the local backing device step for the remote device
               - check if any drbd device is using the local port,
                 if yes abort
               - check if any remote drbd device is using the remote
                 port, if yes abort (for now)
               - bind our net port
               - bind the remote net port
           """
           self.Attach()
           if self.minor is not None:
             logger.Info("Already assembled")
             return True
           result = super(DRBDev, self).Assemble()
           if not result:
             return result
           minor = self._FindUnusedMinor()
           if minor is None:
             raise errors.BlockDeviceError("Not enough free minors for DRBD!")
           need_localdev_teardown = False
           if self._children[0]:
             result = self._AssembleLocal(minor, self._children[0].dev_path,
                                          self._children[1].dev_path)
             if not result:
               return False
             need_localdev_teardown = True
           if self._lhost and self._lport and self._rhost and self._rport:
             result = self._AssembleNet(minor,
                                        (self._lhost, self._lport,
                                         self._rhost, self._rport),
                                        "C")
             if not result:
               if need_localdev_teardown:
                 # we will ignore failures from this
                 logger.Error("net setup failed, tearing down local device")
                 self._ShutdownAll(minor)
               return False
           self._SetFromMinor(minor)
           return True
         def Shutdown(self):
           """Shutdown the DRBD device.
           """
           if self.minor is None and not self.Attach():
             logger.Info("DRBD device not attached to a device during Shutdown")
             return True
           if not self._ShutdownAll(self.minor):
             return False
           self.minor = None
           self.dev_path = None
           return True
         def Attach(self):
           """Find a DRBD device which matches our config and attach to it.
           In case of partially attached (local device matches but no network
           setup), we perform the network attach. If successful, we re-test
           the attach if can return success.
           """
           for minor in self._GetUsedDevs():
             info = self._GetDevInfo(minor)
             match_l = self._MatchesLocal(info)
             match_r = self._MatchesNet(info)
             if match_l and match_r:
               break
             if match_l and not match_r and "local_addr" not in info:
               res_r = self._AssembleNet(minor,
                                         (self._lhost, self._lport,
                                          self._rhost, self._rport),
                                         "C")
               if res_r and self._MatchesNet(self._GetDevInfo(minor)):
                 break
           else:
             minor = None
           self._SetFromMinor(minor)
           return minor is not None
         def Open(self, force=False):
           """Make the local state primary.
           If the 'force' parameter is given, the '--do-what-I-say' parameter
           is given. Since this is a pottentialy dangerous operation, the
           force flag should be only given after creation, when it actually
           has to be given.
           """
           if self.minor is None and not self.Attach():
             logger.Error("DRBD cannot attach to a device during open")
             return False
           cmd = ["drbdsetup", self.dev_path, "primary"]
           if force:
             cmd.append("--do-what-I-say")
           result = utils.RunCmd(cmd)
           if result.failed:
             logger.Error("Can't make drbd device primary: %s" % result.output)
             return False
           return True
         def Close(self):
           """Make the local state secondary.
           This will, of course, fail if the device is in use.
           """
           if self.minor is None and not self.Attach():
             logger.Info("Instance not attached to a device")
             raise errors.BlockDeviceError("Can't find device")
           result = utils.RunCmd(["drbdsetup", self.dev_path, "secondary"])
           if result.failed:
             logger.Error("Can't switch drbd device to secondary: %s" % result.output)
             raise errors.BlockDeviceError("Can't switch drbd device to secondary")
         def SetSyncSpeed(self, kbytes):
           """Set the speed of the DRBD syncer.
           """
           children_result = super(DRBDev, self).SetSyncSpeed(kbytes)
           if self.minor is None:
             logger.Info("Instance not attached to a device")
             return False
           result = utils.RunCmd(["drbdsetup", self.dev_path, "syncer", "-r", "%d" %
                                  kbytes])
           if result.failed:
             logger.Error("Can't change syncer rate: %s " % result.fail_reason)
           return not result.failed and children_result
         def GetSyncStatus(self):
           """Returns the sync status of the device.
           Returns:
            (sync_percent, estimated_time)
           If sync_percent is None, it means all is ok
           If estimated_time is None, it means we can't esimate
           the time needed, otherwise it's the time left in seconds
           """
           if self.minor is None and not self.Attach():
             raise errors.BlockDeviceError("Can't attach to device in GetSyncStatus")
           proc_info = self._MassageProcData(self._GetProcData())
           if self.minor not in proc_info:
             raise errors.BlockDeviceError("Can't find myself in /proc (minor %d)" %
                                           self.minor)
           line = proc_info[self.minor]
           match = re.match("^.*sync'ed: *([0-9.]+)%.*"
                            " finish: ([0-9]+):([0-9]+):([0-9]+) .*$", line)
           if match:
             sync_percent = float(match.group(1))
             hours = int(match.group(2))
             minutes = int(match.group(3))
             seconds = int(match.group(4))
             est_time = hours * 3600 + minutes * 60 + seconds
           else:
             sync_percent = None
             est_time = None
           match = re.match("^ *[0-9]+: cs:([^ ]+).*$", line)
           if not match:
             raise errors.BlockDeviceError("Can't find my data in /proc (minor %d)" %
                                           self.minor)
           client_state = match.group(1)
           is_degraded = client_state != "Connected"
           return sync_percent, est_time, is_degraded
         @staticmethod
         def _MassageProcData(data):
           """Transform the output of _GetProdData into a nicer form.
           Returns:
             a dictionary of minor: joined lines from /proc/drbd for that minor
           """
           lmatch = re.compile("^ *([0-9]+):.*$")
           results = {}
           old_minor = old_line = None
           for line in data:
             lresult = lmatch.match(line)
             if lresult is not None:
               if old_minor is not None:
                 results[old_minor] = old_line
               old_minor = int(lresult.group(1))
               old_line = line
             else:
               if old_minor is not None:
                 old_line += " " + line.strip()
           # add last line
           if old_minor is not None:
             results[old_minor] = old_line
           return results
         def GetStatus(self):
           """Compute the status of the DRBD device
           Note that DRBD devices don't have the STATUS_EXISTING state.
           """
           if self.minor is None and not self.Attach():
             return self.STATUS_UNKNOWN
           data = self._GetProcData()
           match = re.compile("^ *%d: cs:[^ ]+ st:(Primary|Secondary)/.*$" %
                              self.minor)
           for line in data:
             mresult = match.match(line)
             if mresult:
               break
           else:
             logger.Error("Can't find myself!")
             return self.STATUS_UNKNOWN
           state = mresult.group(2)
           if state == "Primary":
             result = self.STATUS_ONLINE
           else:
             result = self.STATUS_STANDBY
           return result
         @staticmethod
         def _ZeroDevice(device):
           """Zero a device.
           This writes until we get ENOSPC.
           """
           f = open(device, "w")
           buf = "\0" * 1048576
           try:
             while True:
               f.write(buf)
           except IOError, err:
             if err.errno != errno.ENOSPC:
               raise
         @classmethod
         def Create(cls, unique_id, children, size):
           """Create a new DRBD device.
           Since DRBD devices are not created per se, just assembled, this
           function just zeroes the meta device.
           """
           if len(children) != 2:
             raise errors.ProgrammerError("Invalid setup for the drbd device")
           meta = children[1]
           meta.Assemble()
           if not meta.Attach():
             raise errors.BlockDeviceError("Can't attach to meta device")
           if not cls._IsValidMeta(meta.dev_path):
             raise errors.BlockDeviceError("Invalid meta device")
           logger.Info("Started zeroing device %s" % meta.dev_path)
           cls._ZeroDevice(meta.dev_path)
           logger.Info("Done zeroing device %s" % meta.dev_path)
           return cls(unique_id, children)
         def Remove(self):
           """Stub remove for DRBD devices.
           """
           return self.Shutdown()
       DEV_MAP = {
         constants.LD_LV: LogicalVolume,
         constants.LD_MD_R1: MDRaid1,
         constants.LD_DRBD7: DRBDev,
+        }
       def FindDevice(dev_type, unique_id, children):
         """Search for an existing, assembled device.
         This will succeed only if the device exists and is assembled, but it
         does not do any actions in order to activate the device.
         """
         if dev_type not in DEV_MAP:
           raise errors.ProgrammerError("Invalid block device type '%s'" % dev_type)
         device = DEV_MAP[dev_type](unique_id, children)
         if not device.Attach():
           return None
         return  device
       def AttachOrAssemble(dev_type, unique_id, children):
         """Try to attach or assemble an existing device.
         This will attach to an existing assembled device or will assemble
         the device, as needed, to bring it fully up.
         """
         if dev_type not in DEV_MAP:
           raise errors.ProgrammerError("Invalid block device type '%s'" % dev_type)
         device = DEV_MAP[dev_type](unique_id, children)
         if not device.Attach():
           device.Assemble()
         if not device.Attach():
           raise errors.BlockDeviceError("Can't find a valid block device for"
                                         " %s/%s/%s" %
                                         (dev_type, unique_id, children))
         return device
       def Create(dev_type, unique_id, children, size):
         """Create a device.
         """
         if dev_type not in DEV_MAP:
           raise errors.ProgrammerError("Invalid block device type '%s'" % dev_type)
         device = DEV_MAP[dev_type].Create(unique_id, children, size)
         return device

Synnefo » snf-ganeti

root / lib / bdev.py @ 770fe0f9