Synnefo » snf-ganeti » ganeti-local

import pyparsing as pyp

class DRBD8(BaseDRBD):

  """DRBD v8.x 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.

  """

  _DRBD_MAJOR = 147

  _MAX_MINORS = 255

  _PARSE_SHOW = None

  def __init__(self, unique_id, children):

    super(DRBD8, self).__init__(unique_id, children)

    self.major = self._DRBD_MAJOR

    [kmaj, kmin, kfix, api, proto] = self._GetVersion()

    if kmaj != 8:

      raise errors.BlockDeviceError("Mismatch in DRBD kernel version and"

                                    " requested ganeti usage: kernel is"

                                    " %s.%s, ganeti wants 8.x" % (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 _InitMeta(cls, minor, dev_path):

    """Initialize a meta device.

    This will not work if the given minor is in use.

    """

    result = utils.RunCmd(["drbdmeta", "--force", cls._DevPath(minor),

                           "v08", dev_path, "0", "create-md"])

    if result.failed:

      raise errors.BlockDeviceError("Can't initialize meta device: %s" %

                                    result.output)

  @classmethod

  def _FindUnusedMinor(cls):

    """Find an unused DRBD device.

    This is specific to 8.x as the minors are allocated dynamically,

    so non-existing numbers up to a max minor count are actually free.

    """

    data = cls._GetProcData()

    unused_line = re.compile("^ *([0-9]+): cs:Unconfigured$")

    used_line = re.compile("^ *([0-9]+): cs:")

    highest = None

    for line in data:

      match = unused_line.match(line)

      if match:

        return int(match.group(1))

      match = used_line.match(line)

      if match:

        minor = int(match.group(1))

        highest = max(highest, minor)

    if highest is None: # there are no minors in use at all

      return 0

    if highest >= cls._MAX_MINORS:

      logger.Error("Error: no free drbd minors!")

      raise errors.BlockDeviceError("Can't find a free DRBD minor")

    return highest + 1

  @classmethod

  def _IsValidMeta(cls, meta_device):

    """Check if the given meta device looks like a valid one.

    """

    minor = cls._FindUnusedMinor()

    minor_path = cls._DevPath(minor)

    result = utils.RunCmd(["drbdmeta", minor_path,

                           "v08", meta_device, "0",

                           "dstate"])

    if result.failed:

      logger.Error("Invalid meta device %s: %s" % (meta_device, result.output))

      return False

    return True

  @classmethod

  def _GetShowParser(cls):

    """Return a parser for `drbd show` output.

    This will either create or return an already-create parser for the

    output of the command `drbd show`.

    """

    if cls._PARSE_SHOW is not None:

      return cls._PARSE_SHOW

    # pyparsing setup

    lbrace = pyp.Literal("{").suppress()

    rbrace = pyp.Literal("}").suppress()

    semi = pyp.Literal(";").suppress()

    # this also converts the value to an int

    number = pyp.Word(pyp.nums).setParseAction(lambda s, l, t:(l, [int(t[0])]))

    comment = pyp.Literal ("#") + pyp.Optional(pyp.restOfLine)

    defa = pyp.Literal("_is_default").suppress()

    dbl_quote = pyp.Literal('"').suppress()

    keyword = pyp.Word(pyp.alphanums + '-')

    # value types

    value = pyp.Word(pyp.alphanums + '_-/.:')

    quoted = dbl_quote + pyp.CharsNotIn('"') + dbl_quote

    addr_port = (pyp.Word(pyp.nums + '.') + pyp.Literal(':').suppress() +

                 number)

    # meta device, extended syntax

    meta_value = ((value ^ quoted) + pyp.Literal('[').suppress() +

                  number + pyp.Word(']').suppress())

    # a statement

    stmt = (~rbrace + keyword + ~lbrace +

            (addr_port ^ value ^ quoted ^ meta_value) +

            pyp.Optional(defa) + semi +

            pyp.Optional(pyp.restOfLine).suppress())

    # an entire section

    section_name = pyp.Word(pyp.alphas + '_')

    section = section_name + lbrace + pyp.ZeroOrMore(pyp.Group(stmt)) + rbrace

    bnf = pyp.ZeroOrMore(pyp.Group(section ^ stmt))

    bnf.ignore(comment)

    cls._PARSE_SHOW = bnf

    return bnf

  @classmethod

  def _GetDevInfo(cls, minor):

    """Get details about a given DRBD minor.

    This return, if available, the local backing device (as a path)

    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 not out:

      return data

    bnf = cls._GetShowParser()

    # run pyparse

    try:

      results = bnf.parseString(out)

    except pyp.ParseException, err:

      raise errors.BlockDeviceError("Can't parse drbdsetup show output: %s" %

                                    str(err))

    # and massage the results into our desired format

    for section in results:

      sname = section[0]

      if sname == "_this_host":

        for lst in section[1:]:

          if lst[0] == "disk":

            data["local_dev"] = lst[1]

          elif lst[0] == "meta-disk":

            data["meta_dev"] = lst[1]

            data["meta_index"] = lst[2]

          elif lst[0] == "address":

            data["local_addr"] = tuple(lst[1:])

      elif sname == "_remote_host":

        for lst in section[1:]:

          if lst[0] == "address":

            data["remote_addr"] = tuple(lst[1:])

    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.

    """

    backend = self._children[0]

    if backend is not None:

      retval = (info["local_dev"] == backend.dev_path)

    else:

      retval = ("local_dev" not in info)

    meta = self._children[1]

    if meta is not None:

      retval = retval and (info["meta_dev"] == meta.dev_path)

      retval = retval and (info["meta_index"] == 0)

    else:

      retval = retval and ("meta_dev" not in info and

                           "meta_index" not in info)

    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

  @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",

                           "--create-device"])

    if result.failed:

      logger.Error("Can't attach local disk: %s" % result.output)

    return not result.failed

  @classmethod

  def _AssembleNet(cls, minor, net_info, protocol,

                   dual_pri=False, hmac=None, secret=None):

    """Configure the network part of the device.

    """

    lhost, lport, rhost, rport = net_info

    args = ["drbdsetup", cls._DevPath(minor), "net",

            "%s:%s" % (lhost, lport), "%s:%s" % (rhost, rport),

            protocol]

    if dual_pri:

      args.append("-m")

    if hmac and secret:

      args.extend(["-a", hmac, "-x", secret])

    result = utils.RunCmd(args)

    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

  def SetSyncSpeed(self, kbytes):

    """Set the speed of the DRBD syncer.

    """

    children_result = super(DRBD8, 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

  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

  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("-o")

    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 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 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(DRBD8, self).Assemble()

    if not result:

      return result

    minor = self._FindUnusedMinor()

    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

  @classmethod

  def _ShutdownAll(cls, minor):

    """Deactivate the device.

    This will, of course, fail if the device is in use.

    """

    result = utils.RunCmd(["drbdsetup", cls._DevPath(minor), "down"])

    if result.failed:

      logger.Error("Can't shutdown drbd device: %s" % result.output)

    return not result.failed

  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 Remove(self):

    """Stub remove for DRBD devices.

    """

    return self.Shutdown()

  @classmethod

  def Create(cls, unique_id, children, size):

    """Create a new DRBD8 device.

    Since DRBD devices are not created per se, just assembled, this

    function only initializes the metadata.

    """

    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._CheckMetaSize(meta.dev_path):

      raise errors.BlockDeviceError("Invalid meta device size")

    cls._InitMeta(cls._FindUnusedMinor(), meta.dev_path)

    if not cls._IsValidMeta(meta.dev_path):

      raise errors.BlockDeviceError("Cannot initalize meta device")

    return cls(unique_id, children)