#!/usr/bin/python
#

# 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.


"""Burnin program

"""

import os
import sys
import optparse
import time
import socket
import urllib
from itertools import izip, islice, cycle
from cStringIO import StringIO

from ganeti import opcodes
from ganeti import constants
from ganeti import cli
from ganeti import errors
from ganeti import utils


USAGE = ("\tburnin -o OS_NAME [options...] instance_name ...")

MAX_RETRIES = 3

class InstanceDown(Exception):
  """The checked instance was not up"""


class BurninFailure(Exception):
  """Failure detected during burning"""


def Usage():
  """Shows program usage information and exits the program."""

  print >> sys.stderr, "Usage:"
  print >> sys.stderr, USAGE
  sys.exit(2)


def Log(msg, indent=0):
  """Simple function that prints out its argument.

  """
  headers = {
    0: "- ",
    1: "* ",
    2: ""
    }
  sys.stdout.write("%*s%s%s\n" % (2*indent, "",
                                   headers.get(indent, "  "), msg))
  sys.stdout.flush()

def Err(msg, exit_code=1):
  """Simple error logging that prints to stderr.

  """
  sys.stderr.write(msg + "\n")
  sys.stderr.flush()
  sys.exit(exit_code)


class SimpleOpener(urllib.FancyURLopener):
  """A simple url opener"""

  def prompt_user_passwd(self, host, realm, clear_cache = 0):
    """No-interaction version of prompt_user_passwd."""
    return None, None

  def http_error_default(self, url, fp, errcode, errmsg, headers):
    """Custom error handling"""
    # make sure sockets are not left in CLOSE_WAIT, this is similar
    # but with a different exception to the BasicURLOpener class
    _ = fp.read() # throw away data
    fp.close()
    raise InstanceDown("HTTP error returned: code %s, msg %s" %
                       (errcode, errmsg))


class Burner(object):
  """Burner class."""

  def __init__(self):
    """Constructor."""
    utils.SetupLogging(constants.LOG_BURNIN, debug=False, stderr_logging=True)
    self.url_opener = SimpleOpener()
    self._feed_buf = StringIO()
    self.nodes = []
    self.instances = []
    self.to_rem = []
    self.queued_ops = []
    self.opts = None
    self.queue_retry = False
    self.disk_count = self.disk_growth = self.disk_size = None
    self.hvp = self.bep = None
    self.ParseOptions()
    self.cl = cli.GetClient()
    self.GetState()

  def ClearFeedbackBuf(self):
    """Clear the feedback buffer."""
    self._feed_buf.truncate(0)

  def GetFeedbackBuf(self):
    """Return the contents of the buffer."""
    return self._feed_buf.getvalue()

  def Feedback(self, msg):
    """Acumulate feedback in our buffer."""
    self._feed_buf.write("%s %s\n" % (time.ctime(utils.MergeTime(msg[0])),
                                      msg[2]))
    if self.opts.verbose:
      Log(msg, indent=3)

  def MaybeRetry(self, retry_count, msg, fn, *args):
    """Possibly retry a given function execution.

    @type retry_count: int
    @param retry_count: retry counter:
        - 0: non-retryable action
        - 1: last retry for a retryable action
        - MAX_RETRIES: original try for a retryable action
    @type msg: str
    @param msg: the kind of the operation
    @type fn: callable
    @param fn: the function to be called

    """
    try:
      val = fn(*args)
      if retry_count > 0 and retry_count < MAX_RETRIES:
        Log("Idempotent %s succeeded after %d retries" %
            (msg, MAX_RETRIES - retry_count))
      return val
    except Exception, err:
      if retry_count == 0:
        Log("Non-idempotent %s failed, aborting" % (msg, ))
        raise
      elif retry_count == 1:
        Log("Idempotent %s repeated failure, aborting" % (msg, ))
        raise
      else:
        Log("Idempotent %s failed, retry #%d/%d: %s" %
            (msg, MAX_RETRIES - retry_count + 1, MAX_RETRIES, err))
        self.MaybeRetry(retry_count - 1, msg, fn, *args)

  def _ExecOp(self, *ops):
    """Execute one or more opcodes and manage the exec buffer.

    @result: if only opcode has been passed, we return its result;
        otherwise we return the list of results

    """
    job_id = cli.SendJob(ops, cl=self.cl)
    results = cli.PollJob(job_id, cl=self.cl, feedback_fn=self.Feedback)
    if len(ops) == 1:
      return results[0]
    else:
      return results

  def ExecOp(self, retry, *ops):
    """Execute one or more opcodes and manage the exec buffer.

    @result: if only opcode has been passed, we return its result;
        otherwise we return the list of results

    """
    if retry:
      rval = MAX_RETRIES
    else:
      rval = 0
    return self.MaybeRetry(rval, "opcode", self._ExecOp, *ops)

  def ExecOrQueue(self, name, *ops):
    """Execute an opcode and manage the exec buffer."""
    if self.opts.parallel:
      self.queued_ops.append((ops, name))
    else:
      return self.ExecOp(self.queue_retry, *ops)

  def StartBatch(self, retry):
    """Start a new batch of jobs.

    @param retry: whether this is a retryable batch

    """
    self.queued_ops = []
    self.queue_retry = retry

  def CommitQueue(self):
    """Execute all submitted opcodes in case of parallel burnin"""
    if not self.opts.parallel:
      return

    if self.queue_retry:
      rval = MAX_RETRIES
    else:
      rval = 0

    try:
      results = self.MaybeRetry(rval, "jobset", self.ExecJobSet,
                                self.queued_ops)
    finally:
      self.queued_ops = []
    return results

  def ExecJobSet(self, jobs):
    """Execute a set of jobs and return once all are done.

    The method will return the list of results, if all jobs are
    successful. Otherwise, OpExecError will be raised from within
    cli.py.

    """
    self.ClearFeedbackBuf()
    job_ids = [cli.SendJob(row[0], cl=self.cl) for row in jobs]
    Log("Submitted job ID(s) %s" % ", ".join(job_ids), indent=1)
    results = []
    for jid, (_, iname) in zip(job_ids, jobs):
      Log("waiting for job %s for %s" % (jid, iname), indent=2)
      try:
        results.append(cli.PollJob(jid, cl=self.cl, feedback_fn=self.Feedback))
      except Exception, err:
        Log("Job for %s failed: %s" % (iname, err))
    if len(results) != len(jobs):
      raise BurninFailure()
    return results

  def _DoCheckInstances(fn):
    """Decorator for checking instances.

    """
    def wrapper(self, *args, **kwargs):
      val = fn(self, *args, **kwargs)
      for instance in self.instances:
        self._CheckInstanceAlive(instance)
      return val

    return wrapper

  def _DoBatch(retry):
    """Decorator for possible batch operations.

    Must come after the _DoCheckInstances decorator (if any).

    @param retry: whether this is a retryable batch, will be
        passed to StartBatch

    """
    def wrap(fn):
      def batched(self, *args, **kwargs):
        self.StartBatch(retry)
        val = fn(self, *args, **kwargs)
        self.CommitQueue()
        return val
      return batched

    return wrap

  def ParseOptions(self):
    """Parses the command line options.

    In case of command line errors, it will show the usage and exit the
    program.

    """

    parser = optparse.OptionParser(usage="\n%s" % USAGE,
                                   version="%%prog (ganeti) %s" %
                                   constants.RELEASE_VERSION,
                                   option_class=cli.CliOption)

    parser.add_option("-o", "--os", dest="os", default=None,
                      help="OS to use during burnin",
                      metavar="<OS>")
    parser.add_option("--disk-size", dest="disk_size",
                      help="Disk size (determines disk count)",
                      default="128m", type="string", metavar="<size,size,...>")
    parser.add_option("--disk-growth", dest="disk_growth", help="Disk growth",
                      default="128m", type="string", metavar="<size,size,...>")
    parser.add_option("--mem-size", dest="mem_size", help="Memory size",
                      default=128, type="unit", metavar="<size>")
    parser.add_option("-v", "--verbose",
                      action="store_true", dest="verbose", default=False,
                      help="print command execution messages to stdout")
    parser.add_option("--no-replace1", dest="do_replace1",
                      help="Skip disk replacement with the same secondary",
                      action="store_false", default=True)
    parser.add_option("--no-replace2", dest="do_replace2",
                      help="Skip disk replacement with a different secondary",
                      action="store_false", default=True)
    parser.add_option("--no-failover", dest="do_failover",
                      help="Skip instance failovers", action="store_false",
                      default=True)
    parser.add_option("--no-migrate", dest="do_migrate",
                      help="Skip instance live migration",
                      action="store_false", default=True)
    parser.add_option("--no-importexport", dest="do_importexport",
                      help="Skip instance export/import", action="store_false",
                      default=True)
    parser.add_option("--no-startstop", dest="do_startstop",
                      help="Skip instance stop/start", action="store_false",
                      default=True)
    parser.add_option("--no-reinstall", dest="do_reinstall",
                      help="Skip instance reinstall", action="store_false",
                      default=True)
    parser.add_option("--no-reboot", dest="do_reboot",
                      help="Skip instance reboot", action="store_false",
                      default=True)
    parser.add_option("--no-activate-disks", dest="do_activate_disks",
                      help="Skip disk activation/deactivation",
                      action="store_false", default=True)
    parser.add_option("--no-add-disks", dest="do_addremove_disks",
                      help="Skip disk addition/removal",
                      action="store_false", default=True)
    parser.add_option("--no-add-nics", dest="do_addremove_nics",
                      help="Skip NIC addition/removal",
                      action="store_false", default=True)
    parser.add_option("--no-nics", dest="nics",
                      help="No network interfaces", action="store_const",
                      const=[], default=[{}])
    parser.add_option("--rename", dest="rename", default=None,
                      help="Give one unused instance name which is taken"
                           " to start the renaming sequence",
                      metavar="<instance_name>")
    parser.add_option("-t", "--disk-template", dest="disk_template",
                      choices=("diskless", "file", "plain", "drbd"),
                      default="drbd",
                      help="Disk template (diskless, file, plain or drbd)"
                            " [drbd]")
    parser.add_option("-n", "--nodes", dest="nodes", default="",
                      help="Comma separated list of nodes to perform"
                      " the burnin on (defaults to all nodes)")
    parser.add_option("-I", "--iallocator", dest="iallocator",
                      default=None, type="string",
                      help="Perform the allocation using an iallocator"
                      " instead of fixed node spread (node restrictions no"
                      " longer apply, therefore -n/--nodes must not be used")
    parser.add_option("-p", "--parallel", default=False, action="store_true",
                      dest="parallel",
                      help="Enable parallelization of some operations in"
                      " order to speed burnin or to test granular locking")
    parser.add_option("--net-timeout", default=15, type="int",
                      dest="net_timeout",
                      help="The instance check network timeout in seconds"
                      " (defaults to 15 seconds)")
    parser.add_option("-C", "--http-check", default=False, action="store_true",
                      dest="http_check",
                      help="Enable checking of instance status via http,"
                      " looking for /hostname.txt that should contain the"
                      " name of the instance")
    parser.add_option("-K", "--keep-instances", default=False,
                      action="store_true",
                      dest="keep_instances",
                      help="Leave instances on the cluster after burnin,"
                      " for investigation in case of errors or simply"
                      " to use them")


    options, args = parser.parse_args()
    if len(args) < 1 or options.os is None:
      Usage()

    supported_disk_templates = (constants.DT_DISKLESS,
                                constants.DT_FILE,
                                constants.DT_PLAIN,
                                constants.DT_DRBD8)
    if options.disk_template not in supported_disk_templates:
      Err("Unknown disk template '%s'" % options.disk_template)

    if options.disk_template == constants.DT_DISKLESS:
      disk_size = disk_growth = []
      options.do_addremove_disks = False
    else:
      disk_size = [utils.ParseUnit(v) for v in options.disk_size.split(",")]
      disk_growth = [utils.ParseUnit(v)
                     for v in options.disk_growth.split(",")]
      if len(disk_growth) != len(disk_size):
        Err("Wrong disk sizes/growth combination")
    if ((disk_size and options.disk_template == constants.DT_DISKLESS) or
        (not disk_size and options.disk_template != constants.DT_DISKLESS)):
      Err("Wrong disk count/disk template combination")

    self.disk_size = disk_size
    self.disk_growth = disk_growth
    self.disk_count = len(disk_size)

    if options.nodes and options.iallocator:
      Err("Give either the nodes option or the iallocator option, not both")

    self.opts = options
    self.instances = args
    self.bep = {
      constants.BE_MEMORY: options.mem_size,
      constants.BE_VCPUS: 1,
      }
    self.hvp = {}

    socket.setdefaulttimeout(options.net_timeout)

  def GetState(self):
    """Read the cluster state from the config."""
    if self.opts.nodes:
      names = self.opts.nodes.split(",")
    else:
      names = []
    try:
      op = opcodes.OpQueryNodes(output_fields=["name", "offline", "drained"],
                                names=names, use_locking=True)
      result = self.ExecOp(True, op)
    except errors.GenericError, err:
      err_code, msg = cli.FormatError(err)
      Err(msg, exit_code=err_code)
    self.nodes = [data[0] for data in result if not (data[1] or data[2])]

    op_diagos = opcodes.OpDiagnoseOS(output_fields=["name", "valid"], names=[])
    result = self.ExecOp(True, op_diagos)

    if not result:
      Err("Can't get the OS list")

    # filter non-valid OS-es
    os_set = [val[0] for val in result if val[1]]

    if self.opts.os not in os_set:
      Err("OS '%s' not found" % self.opts.os)

  @_DoCheckInstances
  @_DoBatch(False)
  def BurnCreateInstances(self):
    """Create the given instances.

    """
    self.to_rem = []
    mytor = izip(cycle(self.nodes),
                 islice(cycle(self.nodes), 1, None),
                 self.instances)

    Log("Creating instances")
    for pnode, snode, instance in mytor:
      Log("instance %s" % instance, indent=1)
      if self.opts.iallocator:
        pnode = snode = None
        msg = "with iallocator %s" % self.opts.iallocator
      elif self.opts.disk_template not in constants.DTS_NET_MIRROR:
        snode = None
        msg = "on %s" % pnode
      else:
        msg = "on %s, %s" % (pnode, snode)

      Log(msg, indent=2)

      op = opcodes.OpCreateInstance(instance_name=instance,
                                    disks = [ {"size": size}
                                              for size in self.disk_size],
                                    disk_template=self.opts.disk_template,
                                    nics=self.opts.nics,
                                    mode=constants.INSTANCE_CREATE,
                                    os_type=self.opts.os,
                                    pnode=pnode,
                                    snode=snode,
                                    start=True,
                                    ip_check=True,
                                    wait_for_sync=True,
                                    file_driver="loop",
                                    file_storage_dir=None,
                                    iallocator=self.opts.iallocator,
                                    beparams=self.bep,
                                    hvparams=self.hvp,
                                    )

      self.ExecOrQueue(instance, op)
      self.to_rem.append(instance)

  @_DoBatch(False)
  def BurnGrowDisks(self):
    """Grow both the os and the swap disks by the requested amount, if any."""
    Log("Growing disks")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      for idx, growth in enumerate(self.disk_growth):
        if growth > 0:
          op = opcodes.OpGrowDisk(instance_name=instance, disk=idx,
                                  amount=growth, wait_for_sync=True)
          Log("increase disk/%s by %s MB" % (idx, growth), indent=2)
          self.ExecOrQueue(instance, op)

  @_DoBatch(True)
  def BurnReplaceDisks1D8(self):
    """Replace disks on primary and secondary for drbd8."""
    Log("Replacing disks on the same nodes")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      ops = []
      for mode in constants.REPLACE_DISK_SEC, constants.REPLACE_DISK_PRI:
        op = opcodes.OpReplaceDisks(instance_name=instance,
                                    mode=mode,
                                    disks=[i for i in range(self.disk_count)])
        Log("run %s" % mode, indent=2)
        ops.append(op)
      self.ExecOrQueue(instance, *ops)

  @_DoBatch(True)
  def BurnReplaceDisks2(self):
    """Replace secondary node."""
    Log("Changing the secondary node")
    mode = constants.REPLACE_DISK_CHG

    mytor = izip(islice(cycle(self.nodes), 2, None),
                 self.instances)
    for tnode, instance in mytor:
      Log("instance %s" % instance, indent=1)
      if self.opts.iallocator:
        tnode = None
        msg = "with iallocator %s" % self.opts.iallocator
      else:
        msg = tnode
      op = opcodes.OpReplaceDisks(instance_name=instance,
                                  mode=mode,
                                  remote_node=tnode,
                                  iallocator=self.opts.iallocator,
                                  disks=[i for i in range(self.disk_count)])
      Log("run %s %s" % (mode, msg), indent=2)
      self.ExecOrQueue(instance, op)

  @_DoCheckInstances
  @_DoBatch(False)
  def BurnFailover(self):
    """Failover the instances."""
    Log("Failing over instances")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      op = opcodes.OpFailoverInstance(instance_name=instance,
                                      ignore_consistency=False)

      self.ExecOrQueue(instance, op)

  @_DoBatch(False)
  def BurnMigrate(self):
    """Migrate the instances."""
    Log("Migrating instances")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      op1 = opcodes.OpMigrateInstance(instance_name=instance, live=True,
                                      cleanup=False)

      op2 = opcodes.OpMigrateInstance(instance_name=instance, live=True,
                                      cleanup=True)
      Log("migration and migration cleanup", indent=2)
      self.ExecOrQueue(instance, op1, op2)

  @_DoCheckInstances
  @_DoBatch(False)
  def BurnImportExport(self):
    """Export the instance, delete it, and import it back.

    """
    Log("Exporting and re-importing instances")
    mytor = izip(cycle(self.nodes),
                 islice(cycle(self.nodes), 1, None),
                 islice(cycle(self.nodes), 2, None),
                 self.instances)

    for pnode, snode, enode, instance in mytor:
      Log("instance %s" % instance, indent=1)
      # read the full name of the instance
      nam_op = opcodes.OpQueryInstances(output_fields=["name"],
                                        names=[instance], use_locking=True)
      full_name = self.ExecOp(False, nam_op)[0][0]

      if self.opts.iallocator:
        pnode = snode = None
        import_log_msg = ("import from %s"
                          " with iallocator %s" %
                          (enode, self.opts.iallocator))
      elif self.opts.disk_template not in constants.DTS_NET_MIRROR:
        snode = None
        import_log_msg = ("import from %s to %s" %
                          (enode, pnode))
      else:
        import_log_msg = ("import from %s to %s, %s" %
                          (enode, pnode, snode))

      exp_op = opcodes.OpExportInstance(instance_name=instance,
                                           target_node=enode,
                                           shutdown=True)
      rem_op = opcodes.OpRemoveInstance(instance_name=instance,
                                        ignore_failures=True)
      imp_dir = os.path.join(constants.EXPORT_DIR, full_name)
      imp_op = opcodes.OpCreateInstance(instance_name=instance,
                                        disks = [ {"size": size}
                                                  for size in self.disk_size],
                                        disk_template=self.opts.disk_template,
                                        nics=self.opts.nics,
                                        mode=constants.INSTANCE_IMPORT,
                                        src_node=enode,
                                        src_path=imp_dir,
                                        pnode=pnode,
                                        snode=snode,
                                        start=True,
                                        ip_check=True,
                                        wait_for_sync=True,
                                        file_storage_dir=None,
                                        file_driver="loop",
                                        iallocator=self.opts.iallocator,
                                        beparams=self.bep,
                                        hvparams=self.hvp,
                                        )

      erem_op = opcodes.OpRemoveExport(instance_name=instance)

      Log("export to node %s" % enode, indent=2)
      Log("remove instance", indent=2)
      Log(import_log_msg, indent=2)
      Log("remove export", indent=2)
      self.ExecOrQueue(instance, exp_op, rem_op, imp_op, erem_op)

  def StopInstanceOp(self, instance):
    """Stop given instance."""
    return opcodes.OpShutdownInstance(instance_name=instance)

  def StartInstanceOp(self, instance):
    """Start given instance."""
    return opcodes.OpStartupInstance(instance_name=instance, force=False)

  def RenameInstanceOp(self, instance, instance_new):
    """Rename instance."""
    return opcodes.OpRenameInstance(instance_name=instance,
                                    new_name=instance_new)

  @_DoCheckInstances
  @_DoBatch(True)
  def BurnStopStart(self):
    """Stop/start the instances."""
    Log("Stopping and starting instances")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      op1 = self.StopInstanceOp(instance)
      op2 = self.StartInstanceOp(instance)
      self.ExecOrQueue(instance, op1, op2)

  @_DoBatch(False)
  def BurnRemove(self):
    """Remove the instances."""
    Log("Removing instances")
    for instance in self.to_rem:
      Log("instance %s" % instance, indent=1)
      op = opcodes.OpRemoveInstance(instance_name=instance,
                                    ignore_failures=True)
      self.ExecOrQueue(instance, op)

  def BurnRename(self):
    """Rename the instances.

    Note that this function will not execute in parallel, since we
    only have one target for rename.

    """
    Log("Renaming instances")
    rename = self.opts.rename
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      op_stop1 = self.StopInstanceOp(instance)
      op_stop2 = self.StopInstanceOp(rename)
      op_rename1 = self.RenameInstanceOp(instance, rename)
      op_rename2 = self.RenameInstanceOp(rename, instance)
      op_start1 = self.StartInstanceOp(rename)
      op_start2 = self.StartInstanceOp(instance)
      self.ExecOp(False, op_stop1, op_rename1, op_start1)
      self._CheckInstanceAlive(rename)
      self.ExecOp(False, op_stop2, op_rename2, op_start2)
      self._CheckInstanceAlive(instance)

  @_DoCheckInstances
  @_DoBatch(True)
  def BurnReinstall(self):
    """Reinstall the instances."""
    Log("Reinstalling instances")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      op1 = self.StopInstanceOp(instance)
      op2 = opcodes.OpReinstallInstance(instance_name=instance)
      Log("reinstall without passing the OS", indent=2)
      op3 = opcodes.OpReinstallInstance(instance_name=instance,
                                        os_type=self.opts.os)
      Log("reinstall specifying the OS", indent=2)
      op4 = self.StartInstanceOp(instance)
      self.ExecOrQueue(instance, op1, op2, op3, op4)

  @_DoCheckInstances
  @_DoBatch(True)
  def BurnReboot(self):
    """Reboot the instances."""
    Log("Rebooting instances")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      ops = []
      for reboot_type in constants.REBOOT_TYPES:
        op = opcodes.OpRebootInstance(instance_name=instance,
                                      reboot_type=reboot_type,
                                      ignore_secondaries=False)
        Log("reboot with type '%s'" % reboot_type, indent=2)
        ops.append(op)
      self.ExecOrQueue(instance, *ops)

  @_DoCheckInstances
  @_DoBatch(True)
  def BurnActivateDisks(self):
    """Activate and deactivate disks of the instances."""
    Log("Activating/deactivating disks")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      op_start = self.StartInstanceOp(instance)
      op_act = opcodes.OpActivateInstanceDisks(instance_name=instance)
      op_deact = opcodes.OpDeactivateInstanceDisks(instance_name=instance)
      op_stop = self.StopInstanceOp(instance)
      Log("activate disks when online", indent=2)
      Log("activate disks when offline", indent=2)
      Log("deactivate disks (when offline)", indent=2)
      self.ExecOrQueue(instance, op_act, op_stop, op_act, op_deact, op_start)

  @_DoCheckInstances
  @_DoBatch(False)
  def BurnAddRemoveDisks(self):
    """Add and remove an extra disk for the instances."""
    Log("Adding and removing disks")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      op_add = opcodes.OpSetInstanceParams(\
        instance_name=instance,
        disks=[(constants.DDM_ADD, {"size": self.disk_size[0]})])
      op_rem = opcodes.OpSetInstanceParams(\
        instance_name=instance, disks=[(constants.DDM_REMOVE, {})])
      op_stop = self.StopInstanceOp(instance)
      op_start = self.StartInstanceOp(instance)
      Log("adding a disk", indent=2)
      Log("removing last disk", indent=2)
      self.ExecOrQueue(instance, op_add, op_stop, op_rem, op_start)

  @_DoBatch(False)
  def BurnAddRemoveNICs(self):
    """Add and remove an extra NIC for the instances."""
    Log("Adding and removing NICs")
    for instance in self.instances:
      Log("instance %s" % instance, indent=1)
      op_add = opcodes.OpSetInstanceParams(\
        instance_name=instance, nics=[(constants.DDM_ADD, {})])
      op_rem = opcodes.OpSetInstanceParams(\
        instance_name=instance, nics=[(constants.DDM_REMOVE, {})])
      Log("adding a NIC", indent=2)
      Log("removing last NIC", indent=2)
      self.ExecOrQueue(instance, op_add, op_rem)

  def _CheckInstanceAlive(self, instance):
    """Check if an instance is alive by doing http checks.

    This will try to retrieve the url on the instance /hostname.txt
    and check that it contains the hostname of the instance. In case
    we get ECONNREFUSED, we retry up to the net timeout seconds, for
    any other error we abort.

    """
    if not self.opts.http_check:
      return
    end_time = time.time() + self.opts.net_timeout
    url = None
    while time.time() < end_time and url is None:
      try:
        url = self.url_opener.open("http://%s/hostname.txt" % instance)
      except IOError:
        # here we can have connection refused, no route to host, etc.
        time.sleep(1)
    if url is None:
      raise InstanceDown(instance, "Cannot contact instance")
    hostname = url.read().strip()
    url.close()
    if hostname != instance:
      raise InstanceDown(instance, ("Hostname mismatch, expected %s, got %s" %
                                    (instance, hostname)))

  def BurninCluster(self):
    """Test a cluster intensively.

    This will create instances and then start/stop/failover them.
    It is safe for existing instances but could impact performance.

    """

    opts = self.opts

    Log("Testing global parameters")

    if (len(self.nodes) == 1 and
        opts.disk_template not in (constants.DT_DISKLESS, constants.DT_PLAIN,
                                   constants.DT_FILE)):
      Err("When one node is available/selected the disk template must"
          " be 'diskless', 'file' or 'plain'")

    has_err = True
    try:
      self.BurnCreateInstances()
      if opts.do_replace1 and opts.disk_template in constants.DTS_NET_MIRROR:
        self.BurnReplaceDisks1D8()
      if (opts.do_replace2 and len(self.nodes) > 2 and
          opts.disk_template in constants.DTS_NET_MIRROR) :
        self.BurnReplaceDisks2()

      if (opts.disk_template != constants.DT_DISKLESS and
          utils.any(self.disk_growth, lambda n: n > 0)):
        self.BurnGrowDisks()

      if opts.do_failover and opts.disk_template in constants.DTS_NET_MIRROR:
        self.BurnFailover()

      if opts.do_migrate and opts.disk_template == constants.DT_DRBD8:
        self.BurnMigrate()

      if (opts.do_importexport and
          opts.disk_template not in (constants.DT_DISKLESS,
                                     constants.DT_FILE)):
        self.BurnImportExport()

      if opts.do_reinstall:
        self.BurnReinstall()

      if opts.do_reboot:
        self.BurnReboot()

      if opts.do_addremove_disks:
        self.BurnAddRemoveDisks()

      if opts.do_addremove_nics:
        self.BurnAddRemoveNICs()

      if opts.do_activate_disks:
        self.BurnActivateDisks()

      if opts.rename:
        self.BurnRename()

      if opts.do_startstop:
        self.BurnStopStart()

      has_err = False
    finally:
      if has_err:
        Log("Error detected: opcode buffer follows:\n\n")
        Log(self.GetFeedbackBuf())
        Log("\n\n")
      if not self.opts.keep_instances:
        try:
          self.BurnRemove()
        except Exception, err:
          if has_err: # already detected errors, so errors in removal
                      # are quite expected
            Log("Note: error detected during instance remove: %s" % str(err))
          else: # non-expected error
            raise

    return 0


def main():
  """Main function"""

  burner = Burner()
  return burner.BurninCluster()


if __name__ == "__main__":
  main()