Synnefo » snf-ganeti

#!/usr/bin/python -u

#

# 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.

"""Master daemon program.

Some classes deviates from the standard style guide since the

inheritance from parent classes requires it.

"""

import os

import errno

import sys

import SocketServer

import time

import collections

import Queue

import random

import signal

import simplejson

import logging

from cStringIO import StringIO

from optparse import OptionParser

from ganeti import config

from ganeti import constants

from ganeti import mcpu

from ganeti import opcodes

from ganeti import jqueue

from ganeti import locking

from ganeti import luxi

from ganeti import utils

from ganeti import errors

from ganeti import ssconf

from ganeti import workerpool

from ganeti import rpc

from ganeti import bootstrap

CLIENT_REQUEST_WORKERS = 16

EXIT_NOTMASTER = constants.EXIT_NOTMASTER

EXIT_NODESETUP_ERROR = constants.EXIT_NODESETUP_ERROR

class ClientRequestWorker(workerpool.BaseWorker):

  def RunTask(self, server, request, client_address):

    """Process the request.

    This is copied from the code in ThreadingMixIn.

    """

    try:

      server.finish_request(request, client_address)

      server.close_request(request)

    except:

      server.handle_error(request, client_address)

      server.close_request(request)

class IOServer(SocketServer.UnixStreamServer):

  """IO thread class.

  This class takes care of initializing the other threads, setting

  signal handlers (which are processed only in this thread), and doing

  cleanup at shutdown.

  """

  def __init__(self, address, rqhandler):

    """IOServer constructor

    Args:

      address: the address to bind this IOServer to

      rqhandler: RequestHandler type object

    """

    SocketServer.UnixStreamServer.__init__(self, address, rqhandler)

    # We'll only start threads once we've forked.

    self.context = None

    self.request_workers = None

  def setup_queue(self):

    self.context = GanetiContext()

    self.request_workers = workerpool.WorkerPool(CLIENT_REQUEST_WORKERS,

                                                 ClientRequestWorker)

  def process_request(self, request, client_address):

    """Add task to workerpool to process request.

    """

    self.request_workers.AddTask(self, request, client_address)

  def serve_forever(self):

    """Handle one request at a time until told to quit."""

    sighandler = utils.SignalHandler([signal.SIGINT, signal.SIGTERM])

    try:

      while not sighandler.called:

        self.handle_request()

    finally:

      sighandler.Reset()

  def server_cleanup(self):

    """Cleanup the server.

    This involves shutting down the processor threads and the master

    socket.

    """

    try:

      self.server_close()

    finally:

      if self.request_workers:

        self.request_workers.TerminateWorkers()

      if self.context:

        self.context.jobqueue.Shutdown()

class ClientRqHandler(SocketServer.BaseRequestHandler):

  """Client handler"""

  EOM = '\3'

  READ_SIZE = 4096

  def setup(self):

    self._buffer = ""

    self._msgs = collections.deque()

    self._ops = ClientOps(self.server)

  def handle(self):

    while True:

      msg = self.read_message()

      if msg is None:

        logging.info("client closed connection")

        break

      request = simplejson.loads(msg)

      logging.debug("request: %s", request)

      if not isinstance(request, dict):

        logging.error("wrong request received: %s", msg)

        break

      method = request.get(luxi.KEY_METHOD, None)

      args = request.get(luxi.KEY_ARGS, None)

      if method is None or args is None:

        logging.error("no method or args in request")

        break

      success = False

      try:

        result = self._ops.handle_request(method, args)

        success = True

      except errors.GenericError, err:

        success = False

        result = (err.__class__.__name__, err.args)

      except:

        logging.error("Unexpected exception", exc_info=True)

        err = sys.exc_info()

        result = "Caught exception: %s" % str(err[1])

      response = {

        luxi.KEY_SUCCESS: success,

        luxi.KEY_RESULT: result,

        }

      logging.debug("response: %s", response)

      self.send_message(simplejson.dumps(response))

  def read_message(self):

    while not self._msgs:

      data = self.request.recv(self.READ_SIZE)

      if not data:

        return None

      new_msgs = (self._buffer + data).split(self.EOM)

      self._buffer = new_msgs.pop()

      self._msgs.extend(new_msgs)

    return self._msgs.popleft()

  def send_message(self, msg):

    #print "sending", msg

    self.request.sendall(msg + self.EOM)

class ClientOps:

  """Class holding high-level client operations."""

  def __init__(self, server):

    self.server = server

  def handle_request(self, method, args):

    queue = self.server.context.jobqueue

    # TODO: Parameter validation

    if method == luxi.REQ_SUBMIT_JOB:

      ops = [opcodes.OpCode.LoadOpCode(state) for state in args]

      return queue.SubmitJob(ops)

    elif method == luxi.REQ_CANCEL_JOB:

      job_id = args

      return queue.CancelJob(job_id)

    elif method == luxi.REQ_ARCHIVE_JOB:

      job_id = args

      return queue.ArchiveJob(job_id)

    elif method == luxi.REQ_AUTOARCHIVE_JOBS:

      age = args

      return queue.AutoArchiveJobs(age)

    elif method == luxi.REQ_WAIT_FOR_JOB_CHANGE:

      (job_id, fields, prev_job_info, prev_log_serial, timeout) = args

      return queue.WaitForJobChanges(job_id, fields, prev_job_info,

                                     prev_log_serial, timeout)

    elif method == luxi.REQ_QUERY_JOBS:

      (job_ids, fields) = args

      return queue.QueryJobs(job_ids, fields)

    elif method == luxi.REQ_QUERY_INSTANCES:

      (names, fields) = args

      op = opcodes.OpQueryInstances(names=names, output_fields=fields)

      return self._Query(op)

    elif method == luxi.REQ_QUERY_NODES:

      (names, fields) = args

      op = opcodes.OpQueryNodes(names=names, output_fields=fields)

      return self._Query(op)

    elif method == luxi.REQ_QUERY_EXPORTS:

      nodes = args

      op = opcodes.OpQueryExports(nodes=nodes)

      return self._Query(op)

    elif method == luxi.REQ_QUERY_CONFIG_VALUES:

      fields = args

      op = opcodes.OpQueryConfigValues(output_fields=fields)

      return self._Query(op)

    elif method == luxi.REQ_QUEUE_SET_DRAIN_FLAG:

      drain_flag = args

      return queue.SetDrainFlag(drain_flag)

    else:

      raise ValueError("Invalid operation")

  def _DummyLog(self, *args):

    pass

  def _Query(self, op):

    """Runs the specified opcode and returns the result.

    """

    proc = mcpu.Processor(self.server.context)

    # TODO: Where should log messages go?

    return proc.ExecOpCode(op, self._DummyLog, None)

class GanetiContext(object):

  """Context common to all ganeti threads.

  This class creates and holds common objects shared by all threads.

  """

  _instance = None

  def __init__(self):

    """Constructs a new GanetiContext object.

    There should be only a GanetiContext object at any time, so this

    function raises an error if this is not the case.

    """

    assert self.__class__._instance is None, "double GanetiContext instance"

    # Create global configuration object

    self.cfg = config.ConfigWriter()

    # Locking manager

    self.glm = locking.GanetiLockManager(

                self.cfg.GetNodeList(),

                self.cfg.GetInstanceList())

    # Job queue

    self.jobqueue = jqueue.JobQueue(self)

    # setting this also locks the class against attribute modifications

    self.__class__._instance = self

  def __setattr__(self, name, value):

    """Setting GanetiContext attributes is forbidden after initialization.

    """

    assert self.__class__._instance is None, "Attempt to modify Ganeti Context"

    object.__setattr__(self, name, value)

  def AddNode(self, node):

    """Adds a node to the configuration and lock manager.

    """

    # Add it to the configuration

    self.cfg.AddNode(node)

    # If preseeding fails it'll not be added

    self.jobqueue.AddNode(node)

    # Add the new node to the Ganeti Lock Manager

    self.glm.add(locking.LEVEL_NODE, node.name)

  def ReaddNode(self, node):

    """Updates a node that's already in the configuration

    """

    # Synchronize the queue again

    self.jobqueue.AddNode(node)

  def RemoveNode(self, name):

    """Removes a node from the configuration and lock manager.

    """

    # Remove node from configuration

    self.cfg.RemoveNode(name)

    # Notify job queue

    self.jobqueue.RemoveNode(name)

    # Remove the node from the Ganeti Lock Manager

    self.glm.remove(locking.LEVEL_NODE, name)

def ParseOptions():

  """Parse the command line options.

  Returns:

    (options, args) as from OptionParser.parse_args()

  """

  parser = OptionParser(description="Ganeti master daemon",

                        usage="%prog [-f] [-d]",

                        version="%%prog (ganeti) %s" %

                        constants.RELEASE_VERSION)

  parser.add_option("-f", "--foreground", dest="fork",

                    help="Don't detach from the current terminal",

                    default=True, action="store_false")

  parser.add_option("-d", "--debug", dest="debug",

                    help="Enable some debug messages",

                    default=False, action="store_true")

  options, args = parser.parse_args()

  return options, args

def CheckAgreement():

  """Check the agreement on who is the master.

  The function uses a very simple algorithm: we must get more positive

  than negative answers. Since in most of the cases we are the master,

  we'll use our own config file for getting the node list. In the

  future we could collect the current node list from our (possibly

  obsolete) known nodes.

  In order to account for cold-start of all nodes, we retry for up to

  a minute until we get a real answer as the top-voted one. If the

  nodes are more out-of-sync, for now manual startup of the master

  should be attempted.

  Note that for a even number of nodes cluster, we need at least half

  of the nodes (beside ourselves) to vote for us. This creates a

  problem on two-node clusters, since in this case we require the

  other node to be up too to confirm our status.

  """

  myself = utils.HostInfo().name

  #temp instantiation of a config writer, used only to get the node list

  cfg = config.ConfigWriter()

  node_list = cfg.GetNodeList()

  del cfg

  retries = 6

  while retries > 0:

    votes = bootstrap.GatherMasterVotes(node_list)

    if not votes:

      # empty node list, this is a one node cluster

      return True

    if votes[0][0] is None:

      retries -= 1

      time.sleep(10)

      continue

    break

  if retries == 0:

      logging.critical("Cluster inconsistent, most of the nodes didn't answer"

                       " after multiple retries. Aborting startup")

      return False

  # here a real node is at the top of the list

  all_votes = sum(item[1] for item in votes)

  top_node, top_votes = votes[0]

  result = False

  if top_node != myself:

    logging.critical("It seems we are not the master (top-voted node"

                     " is %s)", top_node)

  elif top_votes < all_votes - top_votes:

    logging.critical("It seems we are not the master (%d votes for,"

                     " %d votes against)", top_votes, all_votes - top_votes)

  else:

    result = True

  return result

def main():

  """Main function"""

  options, args = ParseOptions()

  utils.debug = options.debug

  utils.no_fork = True

  rpc.Init()

  try:

    ssconf.CheckMaster(options.debug)

    # we believe we are the master, let's ask the other nodes...

    if not CheckAgreement():

      return

    try:

      os.mkdir(constants.SOCKET_DIR, constants.SOCKET_DIR_MODE)

    except EnvironmentError, err:

      if err.errno != errno.EEXIST:

        raise errors.GenericError("Cannot create socket directory"

          " '%s': %s" % (constants.SOCKET_DIR, err))

    # This is safe to do as the pid file guarantees against

    # concurrent execution.

    utils.RemoveFile(constants.MASTER_SOCKET)

    master = IOServer(constants.MASTER_SOCKET, ClientRqHandler)

  finally:

    rpc.Shutdown()

  # become a daemon

  if options.fork:

    utils.Daemonize(logfile=constants.LOG_MASTERDAEMON,

                    noclose_fds=[master.fileno()])

  utils.WritePidFile(constants.MASTERD_PID)

  try:

    utils.SetupLogging(constants.LOG_MASTERDAEMON, debug=options.debug,

                       stderr_logging=not options.fork)

    logging.info("Ganeti master daemon startup")

    rpc.Init()

    try:

      # activate ip

      master_node = ssconf.SimpleConfigReader().GetMasterNode()

      if not rpc.RpcRunner.call_node_start_master(master_node, False):

        logging.error("Can't activate master IP address")

      master.setup_queue()

      try:

        master.serve_forever()

      finally:

        master.server_cleanup()

    finally:

      rpc.Shutdown()

  finally:

    utils.RemovePidFile(constants.MASTERD_PID)

    utils.RemoveFile(constants.MASTER_SOCKET)

if __name__ == "__main__":

  main()