Synnefo » snf-ganeti

#

#

# Copyright (C) 2010 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.

"""Ganeti RAPI client.

@attention: To use the RAPI client, the application B{must} call

            C{pycurl.global_init} during initialization and

            C{pycurl.global_cleanup} before exiting the process. This is very

            important in multi-threaded programs. See curl_global_init(3) and

            curl_global_cleanup(3) for details. The decorator L{UsesRapiClient}

            can be used.

"""

# No Ganeti-specific modules should be imported. The RAPI client is supposed to

# be standalone.

import logging

import simplejson

import urllib

import threading

import pycurl

try:

  from cStringIO import StringIO

except ImportError:

  from StringIO import StringIO

GANETI_RAPI_PORT = 5080

GANETI_RAPI_VERSION = 2

HTTP_DELETE = "DELETE"

HTTP_GET = "GET"

HTTP_PUT = "PUT"

HTTP_POST = "POST"

HTTP_OK = 200

HTTP_NOT_FOUND = 404

HTTP_APP_JSON = "application/json"

REPLACE_DISK_PRI = "replace_on_primary"

REPLACE_DISK_SECONDARY = "replace_on_secondary"

REPLACE_DISK_CHG = "replace_new_secondary"

REPLACE_DISK_AUTO = "replace_auto"

NODE_ROLE_DRAINED = "drained"

NODE_ROLE_MASTER_CANDIATE = "master-candidate"

NODE_ROLE_MASTER = "master"

NODE_ROLE_OFFLINE = "offline"

NODE_ROLE_REGULAR = "regular"

# Internal constants

_REQ_DATA_VERSION_FIELD = "__version__"

_INST_CREATE_REQV1 = "instance-create-reqv1"

_INST_NIC_PARAMS = frozenset(["mac", "ip", "mode", "link", "bridge"])

_INST_CREATE_V0_DISK_PARAMS = frozenset(["size"])

_INST_CREATE_V0_PARAMS = frozenset([

  "os", "pnode", "snode", "iallocator", "start", "ip_check", "name_check",

  "hypervisor", "file_storage_dir", "file_driver", "dry_run",

  ])

_INST_CREATE_V0_DPARAMS = frozenset(["beparams", "hvparams"])

# Older pycURL versions don't have all error constants

try:

  _CURLE_SSL_CACERT = pycurl.E_SSL_CACERT

  _CURLE_SSL_CACERT_BADFILE = pycurl.E_SSL_CACERT_BADFILE

except AttributeError:

  _CURLE_SSL_CACERT = 60

  _CURLE_SSL_CACERT_BADFILE = 77

_CURL_SSL_CERT_ERRORS = frozenset([

  _CURLE_SSL_CACERT,

  _CURLE_SSL_CACERT_BADFILE,

  ])

class Error(Exception):

  """Base error class for this module.

  """

  pass

class CertificateError(Error):

  """Raised when a problem is found with the SSL certificate.

  """

  pass

class GanetiApiError(Error):

  """Generic error raised from Ganeti API.

  """

  def __init__(self, msg, code=None):

    Error.__init__(self, msg)

    self.code = code

def UsesRapiClient(fn):

  """Decorator for code using RAPI client to initialize pycURL.

  """

  def wrapper(*args, **kwargs):

    # curl_global_init(3) and curl_global_cleanup(3) must be called with only

    # one thread running. This check is just a safety measure -- it doesn't

    # cover all cases.

    assert threading.activeCount() == 1, \

           "Found active threads when initializing pycURL"

    pycurl.global_init(pycurl.GLOBAL_ALL)

    try:

      return fn(*args, **kwargs)

    finally:

      pycurl.global_cleanup()

  return wrapper

def GenericCurlConfig(verbose=False, use_signal=False,

                      use_curl_cabundle=False, cafile=None, capath=None,

                      proxy=None, verify_hostname=False,

                      connect_timeout=None, timeout=None,

                      _pycurl_version_fn=pycurl.version_info):

  """Curl configuration function generator.

  @type verbose: bool

  @param verbose: Whether to set cURL to verbose mode

  @type use_signal: bool

  @param use_signal: Whether to allow cURL to use signals

  @type use_curl_cabundle: bool

  @param use_curl_cabundle: Whether to use cURL's default CA bundle

  @type cafile: string

  @param cafile: In which file we can find the certificates

  @type capath: string

  @param capath: In which directory we can find the certificates

  @type proxy: string

  @param proxy: Proxy to use, None for default behaviour and empty string for

                disabling proxies (see curl_easy_setopt(3))

  @type verify_hostname: bool

  @param verify_hostname: Whether to verify the remote peer certificate's

                          commonName

  @type connect_timeout: number

  @param connect_timeout: Timeout for establishing connection in seconds

  @type timeout: number

  @param timeout: Timeout for complete transfer in seconds (see

                  curl_easy_setopt(3)).

  """

  if use_curl_cabundle and (cafile or capath):

    raise Error("Can not use default CA bundle when CA file or path is set")

  def _ConfigCurl(curl, logger):

    """Configures a cURL object

    @type curl: pycurl.Curl

    @param curl: cURL object

    """

    logger.debug("Using cURL version %s", pycurl.version)

    # pycurl.version_info returns a tuple with information about the used

    # version of libcurl. Item 5 is the SSL library linked to it.

    # e.g.: (3, '7.18.0', 463360, 'x86_64-pc-linux-gnu', 1581, 'GnuTLS/2.0.4',

    # 0, '1.2.3.3', ...)

    sslver = _pycurl_version_fn()[5]

    if not sslver:

      raise Error("No SSL support in cURL")

    lcsslver = sslver.lower()

    if lcsslver.startswith("openssl/"):

      pass

    elif lcsslver.startswith("gnutls/"):

      if capath:

        raise Error("cURL linked against GnuTLS has no support for a"

                    " CA path (%s)" % (pycurl.version, ))

    else:

      raise NotImplementedError("cURL uses unsupported SSL version '%s'" %

                                sslver)

    curl.setopt(pycurl.VERBOSE, verbose)

    curl.setopt(pycurl.NOSIGNAL, not use_signal)

    # Whether to verify remote peer's CN

    if verify_hostname:

      # curl_easy_setopt(3): "When CURLOPT_SSL_VERIFYHOST is 2, that

      # certificate must indicate that the server is the server to which you

      # meant to connect, or the connection fails. [...] When the value is 1,

      # the certificate must contain a Common Name field, but it doesn't matter

      # what name it says. [...]"

      curl.setopt(pycurl.SSL_VERIFYHOST, 2)

    else:

      curl.setopt(pycurl.SSL_VERIFYHOST, 0)

    if cafile or capath or use_curl_cabundle:

      # Require certificates to be checked

      curl.setopt(pycurl.SSL_VERIFYPEER, True)

      if cafile:

        curl.setopt(pycurl.CAINFO, str(cafile))

      if capath:

        curl.setopt(pycurl.CAPATH, str(capath))

      # Not changing anything for using default CA bundle

    else:

      # Disable SSL certificate verification

      curl.setopt(pycurl.SSL_VERIFYPEER, False)

    if proxy is not None:

      curl.setopt(pycurl.PROXY, str(proxy))

    # Timeouts

    if connect_timeout is not None:

      curl.setopt(pycurl.CONNECTTIMEOUT, connect_timeout)

    if timeout is not None:

      curl.setopt(pycurl.TIMEOUT, timeout)

  return _ConfigCurl

class GanetiRapiClient(object):

  """Ganeti RAPI client.

  """

  USER_AGENT = "Ganeti RAPI Client"

  _json_encoder = simplejson.JSONEncoder(sort_keys=True)

  def __init__(self, host, port=GANETI_RAPI_PORT,

               username=None, password=None, logger=logging,

               curl_config_fn=None, curl_factory=None):

    """Initializes this class.

    @type host: string

    @param host: the ganeti cluster master to interact with

    @type port: int

    @param port: the port on which the RAPI is running (default is 5080)

    @type username: string

    @param username: the username to connect with

    @type password: string

    @param password: the password to connect with

    @type curl_config_fn: callable

    @param curl_config_fn: Function to configure C{pycurl.Curl} object

    @param logger: Logging object

    """

    self._username = username

    self._password = password

    self._logger = logger

    self._curl_config_fn = curl_config_fn

    self._curl_factory = curl_factory

    self._base_url = "https://%s:%s" % (host, port)

    if username is not None:

      if password is None:

        raise Error("Password not specified")

    elif password:

      raise Error("Specified password without username")

  def _CreateCurl(self):

    """Creates a cURL object.

    """

    # Create pycURL object if no factory is provided

    if self._curl_factory:

      curl = self._curl_factory()

    else:

      curl = pycurl.Curl()

    # Default cURL settings

    curl.setopt(pycurl.VERBOSE, False)

    curl.setopt(pycurl.FOLLOWLOCATION, False)

    curl.setopt(pycurl.MAXREDIRS, 5)

    curl.setopt(pycurl.NOSIGNAL, True)

    curl.setopt(pycurl.USERAGENT, self.USER_AGENT)

    curl.setopt(pycurl.SSL_VERIFYHOST, 0)

    curl.setopt(pycurl.SSL_VERIFYPEER, False)

    curl.setopt(pycurl.HTTPHEADER, [

      "Accept: %s" % HTTP_APP_JSON,

      "Content-type: %s" % HTTP_APP_JSON,

      ])

    assert ((self._username is None and self._password is None) ^

            (self._username is not None and self._password is not None))

    if self._username:

      # Setup authentication

      curl.setopt(pycurl.HTTPAUTH, pycurl.HTTPAUTH_BASIC)

      curl.setopt(pycurl.USERPWD,

                  str("%s:%s" % (self._username, self._password)))

    # Call external configuration function

    if self._curl_config_fn:

      self._curl_config_fn(curl, self._logger)

    return curl

  @staticmethod

  def _EncodeQuery(query):

    """Encode query values for RAPI URL.

    @type query: list of two-tuples

    @param query: Query arguments

    @rtype: list

    @return: Query list with encoded values

    """

    result = []

    for name, value in query:

      if value is None:

        result.append((name, ""))

      elif isinstance(value, bool):

        # Boolean values must be encoded as 0 or 1

        result.append((name, int(value)))

      elif isinstance(value, (list, tuple, dict)):

        raise ValueError("Invalid query data type %r" % type(value).__name__)

      else:

        result.append((name, value))

    return result

  def _SendRequest(self, method, path, query, content):

    """Sends an HTTP request.

    This constructs a full URL, encodes and decodes HTTP bodies, and

    handles invalid responses in a pythonic way.

    @type method: string

    @param method: HTTP method to use

    @type path: string

    @param path: HTTP URL path

    @type query: list of two-tuples

    @param query: query arguments to pass to urllib.urlencode

    @type content: str or None

    @param content: HTTP body content

    @rtype: str

    @return: JSON-Decoded response

    @raises CertificateError: If an invalid SSL certificate is found

    @raises GanetiApiError: If an invalid response is returned

    """

    assert path.startswith("/")

    curl = self._CreateCurl()

    if content is not None:

      encoded_content = self._json_encoder.encode(content)

    else:

      encoded_content = ""

    # Build URL

    urlparts = [self._base_url, path]

    if query:

      urlparts.append("?")

      urlparts.append(urllib.urlencode(self._EncodeQuery(query)))

    url = "".join(urlparts)

    self._logger.debug("Sending request %s %s (content=%r)",

                       method, url, encoded_content)

    # Buffer for response

    encoded_resp_body = StringIO()

    # Configure cURL

    curl.setopt(pycurl.CUSTOMREQUEST, str(method))

    curl.setopt(pycurl.URL, str(url))

    curl.setopt(pycurl.POSTFIELDS, str(encoded_content))

    curl.setopt(pycurl.WRITEFUNCTION, encoded_resp_body.write)

    try:

      # Send request and wait for response

      try:

        curl.perform()

      except pycurl.error, err:

        if err.args[0] in _CURL_SSL_CERT_ERRORS:

          raise CertificateError("SSL certificate error %s" % err)

        raise GanetiApiError(str(err))

    finally:

      # Reset settings to not keep references to large objects in memory

      # between requests

      curl.setopt(pycurl.POSTFIELDS, "")

      curl.setopt(pycurl.WRITEFUNCTION, lambda _: None)

    # Get HTTP response code

    http_code = curl.getinfo(pycurl.RESPONSE_CODE)

    # Was anything written to the response buffer?

    if encoded_resp_body.tell():

      response_content = simplejson.loads(encoded_resp_body.getvalue())

    else:

      response_content = None

    if http_code != HTTP_OK:

      if isinstance(response_content, dict):

        msg = ("%s %s: %s" %

               (response_content["code"],

                response_content["message"],

                response_content["explain"]))

      else:

        msg = str(response_content)

      raise GanetiApiError(msg, code=http_code)

    return response_content

  def GetVersion(self):

    """Gets the Remote API version running on the cluster.

    @rtype: int

    @return: Ganeti Remote API version

    """

    return self._SendRequest(HTTP_GET, "/version", None, None)

  def GetFeatures(self):

    """Gets the list of optional features supported by RAPI server.

    @rtype: list

    @return: List of optional features

    """

    try:

      return self._SendRequest(HTTP_GET, "/%s/features" % GANETI_RAPI_VERSION,

                               None, None)

    except GanetiApiError, err:

      # Older RAPI servers don't support this resource

      if err.code == HTTP_NOT_FOUND:

        return []

      raise

  def GetOperatingSystems(self):

    """Gets the Operating Systems running in the Ganeti cluster.

    @rtype: list of str

    @return: operating systems

    """

    return self._SendRequest(HTTP_GET, "/%s/os" % GANETI_RAPI_VERSION,

                             None, None)

  def GetInfo(self):

    """Gets info about the cluster.

    @rtype: dict

    @return: information about the cluster

    """

    return self._SendRequest(HTTP_GET, "/%s/info" % GANETI_RAPI_VERSION,

                             None, None)

  def GetClusterTags(self):

    """Gets the cluster tags.

    @rtype: list of str

    @return: cluster tags

    """

    return self._SendRequest(HTTP_GET, "/%s/tags" % GANETI_RAPI_VERSION,

                             None, None)

  def AddClusterTags(self, tags, dry_run=False):

    """Adds tags to the cluster.

    @type tags: list of str

    @param tags: tags to add to the cluster

    @type dry_run: bool

    @param dry_run: whether to perform a dry run

    @rtype: int

    @return: job id

    """

    query = [("tag", t) for t in tags]

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_PUT, "/%s/tags" % GANETI_RAPI_VERSION,

                             query, None)

  def DeleteClusterTags(self, tags, dry_run=False):

    """Deletes tags from the cluster.

    @type tags: list of str

    @param tags: tags to delete

    @type dry_run: bool

    @param dry_run: whether to perform a dry run

    """

    query = [("tag", t) for t in tags]

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_DELETE, "/%s/tags" % GANETI_RAPI_VERSION,

                             query, None)

  def GetInstances(self, bulk=False):

    """Gets information about instances on the cluster.

    @type bulk: bool

    @param bulk: whether to return all information about all instances

    @rtype: list of dict or list of str

    @return: if bulk is True, info about the instances, else a list of instances

    """

    query = []

    if bulk:

      query.append(("bulk", 1))

    instances = self._SendRequest(HTTP_GET,

                                  "/%s/instances" % GANETI_RAPI_VERSION,

                                  query, None)

    if bulk:

      return instances

    else:

      return [i["id"] for i in instances]

  def GetInstance(self, instance):

    """Gets information about an instance.

    @type instance: str

    @param instance: instance whose info to return

    @rtype: dict

    @return: info about the instance

    """

    return self._SendRequest(HTTP_GET,

                             ("/%s/instances/%s" %

                              (GANETI_RAPI_VERSION, instance)), None, None)

  def GetInstanceInfo(self, instance, static=None):

    """Gets information about an instance.

    @type instance: string

    @param instance: Instance name

    @rtype: string

    @return: Job ID

    """

    if static is not None:

      query = [("static", static)]

    else:

      query = None

    return self._SendRequest(HTTP_GET,

                             ("/%s/instances/%s/info" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def CreateInstance(self, mode, name, disk_template, disks, nics,

                     **kwargs):

    """Creates a new instance.

    More details for parameters can be found in the RAPI documentation.

    @type mode: string

    @param mode: Instance creation mode

    @type name: string

    @param name: Hostname of the instance to create

    @type disk_template: string

    @param disk_template: Disk template for instance (e.g. plain, diskless,

                          file, or drbd)

    @type disks: list of dicts

    @param disks: List of disk definitions

    @type nics: list of dicts

    @param nics: List of NIC definitions

    @type dry_run: bool

    @keyword dry_run: whether to perform a dry run

    @rtype: int

    @return: job id

    """

    query = []

    if kwargs.get("dry_run"):

      query.append(("dry-run", 1))

    if _INST_CREATE_REQV1 in self.GetFeatures():

      # All required fields for request data version 1

      body = {

        _REQ_DATA_VERSION_FIELD: 1,

        "mode": mode,

        "name": name,

        "disk_template": disk_template,

        "disks": disks,

        "nics": nics,

        }

      conflicts = set(kwargs.iterkeys()) & set(body.iterkeys())

      if conflicts:

        raise GanetiApiError("Required fields can not be specified as"

                             " keywords: %s" % ", ".join(conflicts))

      body.update((key, value) for key, value in kwargs.iteritems()

                  if key != "dry_run")

    else:

      # Old request format (version 0)

      # The following code must make sure that an exception is raised when an

      # unsupported setting is requested by the caller. Otherwise this can lead

      # to bugs difficult to find. The interface of this function must stay

      # exactly the same for version 0 and 1 (e.g. they aren't allowed to

      # require different data types).

      # Validate disks

      for idx, disk in enumerate(disks):

        unsupported = set(disk.keys()) - _INST_CREATE_V0_DISK_PARAMS

        if unsupported:

          raise GanetiApiError("Server supports request version 0 only, but"

                               " disk %s specifies the unsupported parameters"

                               " %s, allowed are %s" %

                               (idx, unsupported,

                                list(_INST_CREATE_V0_DISK_PARAMS)))

      assert (len(_INST_CREATE_V0_DISK_PARAMS) == 1 and

              "size" in _INST_CREATE_V0_DISK_PARAMS)

      disk_sizes = [disk["size"] for disk in disks]

      # Validate NICs

      if not nics:

        raise GanetiApiError("Server supports request version 0 only, but"

                             " no NIC specified")

      elif len(nics) > 1:

        raise GanetiApiError("Server supports request version 0 only, but"

                             " more than one NIC specified")

      assert len(nics) == 1

      unsupported = set(nics[0].keys()) - _INST_NIC_PARAMS

      if unsupported:

        raise GanetiApiError("Server supports request version 0 only, but"

                             " NIC 0 specifies the unsupported parameters %s,"

                             " allowed are %s" %

                             (unsupported, list(_INST_NIC_PARAMS)))

      # Validate other parameters

      unsupported = (set(kwargs.keys()) - _INST_CREATE_V0_PARAMS -

                     _INST_CREATE_V0_DPARAMS)

      if unsupported:

        allowed = _INST_CREATE_V0_PARAMS.union(_INST_CREATE_V0_DPARAMS)

        raise GanetiApiError("Server supports request version 0 only, but"

                             " the following unsupported parameters are"

                             " specified: %s, allowed are %s" %

                             (unsupported, list(allowed)))

      # All required fields for request data version 0

      body = {

        _REQ_DATA_VERSION_FIELD: 0,

        "name": name,

        "disk_template": disk_template,

        "disks": disk_sizes,

        }

      # NIC fields

      assert len(nics) == 1

      assert not (set(body.keys()) & set(nics[0].keys()))

      body.update(nics[0])

      # Copy supported fields

      assert not (set(body.keys()) & set(kwargs.keys()))

      body.update(dict((key, value) for key, value in kwargs.items()

                       if key in _INST_CREATE_V0_PARAMS))

      # Merge dictionaries

      for i in (value for key, value in kwargs.items()

                if key in _INST_CREATE_V0_DPARAMS):

        assert not (set(body.keys()) & set(i.keys()))

        body.update(i)

      assert not (set(kwargs.keys()) -

                  (_INST_CREATE_V0_PARAMS | _INST_CREATE_V0_DPARAMS))

      assert not (set(body.keys()) & _INST_CREATE_V0_DPARAMS)

    return self._SendRequest(HTTP_POST, "/%s/instances" % GANETI_RAPI_VERSION,

                             query, body)

  def DeleteInstance(self, instance, dry_run=False):

    """Deletes an instance.

    @type instance: str

    @param instance: the instance to delete

    @rtype: int

    @return: job id

    """

    query = []

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_DELETE,

                             ("/%s/instances/%s" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def ModifyInstance(self, instance, **kwargs):

    """Modifies an instance.

    More details for parameters can be found in the RAPI documentation.

    @type instance: string

    @param instance: Instance name

    @rtype: int

    @return: job id

    """

    body = kwargs

    return self._SendRequest(HTTP_PUT,

                             ("/%s/instances/%s/modify" %

                              (GANETI_RAPI_VERSION, instance)), None, body)

  def GetInstanceTags(self, instance):

    """Gets tags for an instance.

    @type instance: str

    @param instance: instance whose tags to return

    @rtype: list of str

    @return: tags for the instance

    """

    return self._SendRequest(HTTP_GET,

                             ("/%s/instances/%s/tags" %

                              (GANETI_RAPI_VERSION, instance)), None, None)

  def AddInstanceTags(self, instance, tags, dry_run=False):

    """Adds tags to an instance.

    @type instance: str

    @param instance: instance to add tags to

    @type tags: list of str

    @param tags: tags to add to the instance

    @type dry_run: bool

    @param dry_run: whether to perform a dry run

    @rtype: int

    @return: job id

    """

    query = [("tag", t) for t in tags]

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_PUT,

                             ("/%s/instances/%s/tags" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def DeleteInstanceTags(self, instance, tags, dry_run=False):

    """Deletes tags from an instance.

    @type instance: str

    @param instance: instance to delete tags from

    @type tags: list of str

    @param tags: tags to delete

    @type dry_run: bool

    @param dry_run: whether to perform a dry run

    """

    query = [("tag", t) for t in tags]

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_DELETE,

                             ("/%s/instances/%s/tags" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def RebootInstance(self, instance, reboot_type=None, ignore_secondaries=None,

                     dry_run=False):

    """Reboots an instance.

    @type instance: str

    @param instance: instance to rebot

    @type reboot_type: str

    @param reboot_type: one of: hard, soft, full

    @type ignore_secondaries: bool

    @param ignore_secondaries: if True, ignores errors for the secondary node

        while re-assembling disks (in hard-reboot mode only)

    @type dry_run: bool

    @param dry_run: whether to perform a dry run

    """

    query = []

    if reboot_type:

      query.append(("type", reboot_type))

    if ignore_secondaries is not None:

      query.append(("ignore_secondaries", ignore_secondaries))

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_POST,

                             ("/%s/instances/%s/reboot" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def ShutdownInstance(self, instance, dry_run=False):

    """Shuts down an instance.

    @type instance: str

    @param instance: the instance to shut down

    @type dry_run: bool

    @param dry_run: whether to perform a dry run

    """

    query = []

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_PUT,

                             ("/%s/instances/%s/shutdown" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def StartupInstance(self, instance, dry_run=False):

    """Starts up an instance.

    @type instance: str

    @param instance: the instance to start up

    @type dry_run: bool

    @param dry_run: whether to perform a dry run

    """

    query = []

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_PUT,

                             ("/%s/instances/%s/startup" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def ReinstallInstance(self, instance, os=None, no_startup=False):

    """Reinstalls an instance.

    @type instance: str

    @param instance: The instance to reinstall

    @type os: str or None

    @param os: The operating system to reinstall. If None, the instance's

        current operating system will be installed again

    @type no_startup: bool

    @param no_startup: Whether to start the instance automatically

    """

    query = []

    if os:

      query.append(("os", os))

    if no_startup:

      query.append(("nostartup", 1))

    return self._SendRequest(HTTP_POST,

                             ("/%s/instances/%s/reinstall" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def ReplaceInstanceDisks(self, instance, disks=None, mode=REPLACE_DISK_AUTO,

                           remote_node=None, iallocator=None, dry_run=False):

    """Replaces disks on an instance.

    @type instance: str

    @param instance: instance whose disks to replace

    @type disks: list of ints

    @param disks: Indexes of disks to replace

    @type mode: str

    @param mode: replacement mode to use (defaults to replace_auto)

    @type remote_node: str or None

    @param remote_node: new secondary node to use (for use with

        replace_new_secondary mode)

    @type iallocator: str or None

    @param iallocator: instance allocator plugin to use (for use with

                       replace_auto mode)

    @type dry_run: bool

    @param dry_run: whether to perform a dry run

    @rtype: int

    @return: job id

    """

    query = [

      ("mode", mode),

      ]

    if disks:

      query.append(("disks", ",".join(str(idx) for idx in disks)))

    if remote_node:

      query.append(("remote_node", remote_node))

    if iallocator:

      query.append(("iallocator", iallocator))

    if dry_run:

      query.append(("dry-run", 1))

    return self._SendRequest(HTTP_POST,

                             ("/%s/instances/%s/replace-disks" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def PrepareExport(self, instance, mode):

    """Prepares an instance for an export.

    @type instance: string

    @param instance: Instance name

    @type mode: string

    @param mode: Export mode

    @rtype: string

    @return: Job ID

    """

    query = [("mode", mode)]

    return self._SendRequest(HTTP_PUT,

                             ("/%s/instances/%s/prepare-export" %

                              (GANETI_RAPI_VERSION, instance)), query, None)

  def ExportInstance(self, instance, mode, destination, shutdown=None,

                     remove_instance=None,

                     x509_key_name=None, destination_x509_ca=None):

    """Exports an instance.

    @type instance: string

    @param instance: Instance name

    @type mode: string

    @param mode: Export mode

    @rtype: string

    @return: Job ID

    """

    body = {

      "destination": destination,

      "mode": mode,

      }

    if shutdown is not None:

      body["shutdown"] = shutdown

    if remove_instance is not None:

      body["remove_instance"] = remove_instance

    if x509_key_name is not None:

      body["x509_key_name"] = x509_key_name

    if destination_x509_ca is not None:

      body["destination_x509_ca"] = destination_x509_ca

    return self._SendRequest(HTTP_PUT,

                             ("/%s/instances/%s/export" %

                              (GANETI_RAPI_VERSION, instance)), None, body)

  def MigrateInstance(self, instance, mode=None, cleanup=None):

    """Migrates an instance.

    @type instance: string

    @param instance: Instance name

    @type mode: string

    @param mode: Migration mode

    @type cleanup: bool

    @param cleanup: Whether to clean up a previously failed migration

    """

    body = {}

    if mode is not None:

      body["mode"] = mode

    if cleanup is not None:

      body["cleanup"] = cleanup

    return self._SendRequest(HTTP_PUT,

                             ("/%s/instances/%s/migrate" %

                              (GANETI_RAPI_VERSION, instance)), None, body)

  def RenameInstance(self, instance, new_name, ip_check=None, name_check=None):

    """Changes the name of an instance.

    @type instance: string

    @param instance: Instance name

    @type new_name: string

    @param new_name: New instance name

    @type ip_check: bool

    @param ip_check: Whether to ensure instance's IP address is inactive

    @type name_check: bool

    @param name_check: Whether to ensure instance's name is resolvable

    """

    body = {

      "new_name": new_name,

      }

    if ip_check is not None:

      body["ip_check"] = ip_check

    if name_check is not None:

      body["name_check"] = name_check

    return self._SendRequest(HTTP_PUT,

                             ("/%s/instances/%s/rename" %

                              (GANETI_RAPI_VERSION, instance)), None, body)