Synnefo » snf-ganeti

#!/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.

"""Configuration management for Ganeti

This module provides the interface to the ganeti cluster configuration.

The configuration data is stored on every node but is updated on the

master only. After each update, the master distributes the data to the

other nodes.

Currently the data storage format is pickle as yaml was initially not

available, then we used it but it was a memory-eating slow beast, so

we reverted to pickle using custom Unpicklers.

"""

import os

import tempfile

import random

from ganeti import errors

from ganeti import logger

from ganeti import utils

from ganeti import constants

from ganeti import rpc

from ganeti import objects

def _my_uuidgen():

  """Poor-man's uuidgen using the uuidgen binary.

  """

  result = utils.RunCmd(["uuidgen", "-r"])

  if result.failed:

    return None

  return result.stdout.rstrip('\n')

try:

  import uuid

  _uuidgen = uuid.uuid4

except ImportError:

  _uuidgen = _my_uuidgen

class ConfigWriter:

  """The interface to the cluster configuration.

  """

  def __init__(self, cfg_file=None, offline=False):

    self._config_data = None

    self._config_time = None

    self._config_size = None

    self._config_inode = None

    self._offline = offline

    if cfg_file is None:

      self._cfg_file = constants.CLUSTER_CONF_FILE

    else:

      self._cfg_file = cfg_file

    self._temporary_ids = set()

    # Note: in order to prevent errors when resolving our name in

    # _DistributeConfig, we compute it here once and reuse it; it's

    # better to raise an error before starting to modify the config

    # file than after it was modified

    self._my_hostname = utils.HostInfo().name

  # this method needs to be static, so that we can call it on the class

  @staticmethod

  def IsCluster():

    """Check if the cluster is configured.

    """

    return os.path.exists(constants.CLUSTER_CONF_FILE)

  def GenerateMAC(self):

    """Generate a MAC for an instance.

    This should check the current instances for duplicates.

    """

    self._OpenConfig()

    self._ReleaseLock()

    prefix = self._config_data.cluster.mac_prefix

    all_macs = self._AllMACs()

    retries = 64

    while retries > 0:

      byte1 = random.randrange(0, 256)

      byte2 = random.randrange(0, 256)

      byte3 = random.randrange(0, 256)

      mac = "%s:%02x:%02x:%02x" % (prefix, byte1, byte2, byte3)

      if mac not in all_macs:

        break

      retries -= 1

    else:

      raise errors.ConfigurationError("Can't generate unique MAC")

    return mac

  def _ComputeAllLVs(self):

    """Compute the list of all LVs.

    """

    self._OpenConfig()

    self._ReleaseLock()

    lvnames = set()

    for instance in self._config_data.instances.values():

      node_data = instance.MapLVsByNode()

      for lv_list in node_data.values():

        lvnames.update(lv_list)

    return lvnames

  def GenerateUniqueID(self, exceptions=None):

    """Generate an unique disk name.

    This checks the current node, instances and disk names for

    duplicates.

    Args:

      - exceptions: a list with some other names which should be checked

                    for uniqueness (used for example when you want to get

                    more than one id at one time without adding each one in

                    turn to the config file

    Returns: the unique id as a string

    """

    existing = set()

    existing.update(self._temporary_ids)

    existing.update(self._ComputeAllLVs())

    existing.update(self._config_data.instances.keys())

    existing.update(self._config_data.nodes.keys())

    if exceptions is not None:

      existing.update(exceptions)

    retries = 64

    while retries > 0:

      unique_id = _uuidgen()

      if unique_id not in existing and unique_id is not None:

        break

    else:

      raise errors.ConfigurationError("Not able generate an unique ID"

                                      " (last tried ID: %s" % unique_id)

    self._temporary_ids.add(unique_id)

    return unique_id

  def _AllMACs(self):

    """Return all MACs present in the config.

    """

    self._OpenConfig()

    self._ReleaseLock()

    result = []

    for instance in self._config_data.instances.values():

      for nic in instance.nics:

        result.append(nic.mac)

    return result

  def VerifyConfig(self):

    """Stub verify function.

    """

    self._OpenConfig()

    self._ReleaseLock()

    result = []

    seen_macs = []

    data = self._config_data

    for instance_name in data.instances:

      instance = data.instances[instance_name]

      if instance.primary_node not in data.nodes:

        result.append("Instance '%s' has invalid primary node '%s'" %

                      (instance_name, instance.primary_node))

      for snode in instance.secondary_nodes:

        if snode not in data.nodes:

          result.append("Instance '%s' has invalid secondary node '%s'" %

                        (instance_name, snode))

      for idx, nic in enumerate(instance.nics):

        if nic.mac in seen_macs:

          result.append("Instance '%s' has NIC %d mac %s duplicate" %

                        (instance_name, idx, nic.mac))

        else:

          seen_macs.append(nic.mac)

    return result

  def SetDiskID(self, disk, node_name):

    """Convert the unique ID to the ID needed on the target nodes.

    This is used only for drbd, which needs ip/port configuration.

    The routine descends down and updates its children also, because

    this helps when the only the top device is passed to the remote

    node.

    """

    if disk.children:

      for child in disk.children:

        self.SetDiskID(child, node_name)

    if disk.logical_id is None and disk.physical_id is not None:

      return

    if disk.dev_type == "drbd":

      pnode, snode, port = disk.logical_id

      if node_name not in (pnode, snode):

        raise errors.ConfigurationError("DRBD device not knowing node %s" %

                                        node_name)

      pnode_info = self.GetNodeInfo(pnode)

      snode_info = self.GetNodeInfo(snode)

      if pnode_info is None or snode_info is None:

        raise errors.ConfigurationError("Can't find primary or secondary node"

                                        " for %s" % str(disk))

      if pnode == node_name:

        disk.physical_id = (pnode_info.secondary_ip, port,

                            snode_info.secondary_ip, port)

      else: # it must be secondary, we tested above

        disk.physical_id = (snode_info.secondary_ip, port,

                            pnode_info.secondary_ip, port)

    else:

      disk.physical_id = disk.logical_id

    return

  def AddTcpUdpPort(self, port):

    """Adds a new port to the available port pool.

    """

    if not isinstance(port, int):

      raise errors.ProgrammerError("Invalid type passed for port")

    self._OpenConfig()

    self._config_data.cluster.tcpudp_port_pool.add(port)

    self._WriteConfig()

  def GetPortList(self):

    """Returns a copy of the current port list.

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data.cluster.tcpudp_port_pool.copy()

  def AllocatePort(self):

    """Allocate a port.

    The port will be taken from the available port pool or from the

    default port range (and in this case we increase

    highest_used_port).

    """

    self._OpenConfig()

    # If there are TCP/IP ports configured, we use them first.

    if self._config_data.cluster.tcpudp_port_pool:

      port = self._config_data.cluster.tcpudp_port_pool.pop()

    else:

      port = self._config_data.cluster.highest_used_port + 1

      if port >= constants.LAST_DRBD_PORT:

        raise errors.ConfigurationError("The highest used port is greater"

                                        " than %s. Aborting." %

                                        constants.LAST_DRBD_PORT)

      self._config_data.cluster.highest_used_port = port

    self._WriteConfig()

    return port

  def GetHostKey(self):

    """Return the rsa hostkey from the config.

    Args: None

    Returns: rsa hostkey

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data.cluster.rsahostkeypub

  def AddInstance(self, instance):

    """Add an instance to the config.

    This should be used after creating a new instance.

    Args:

      instance: the instance object

    """

    if not isinstance(instance, objects.Instance):

      raise errors.ProgrammerError("Invalid type passed to AddInstance")

    if instance.disk_template != constants.DT_DISKLESS:

      all_lvs = instance.MapLVsByNode()

      logger.Info("Instance '%s' DISK_LAYOUT: %s" % (instance.name, all_lvs))

    self._OpenConfig()

    self._config_data.instances[instance.name] = instance

    self._WriteConfig()

  def MarkInstanceUp(self, instance_name):

    """Mark the instance status to up in the config.

    """

    self._OpenConfig()

    if instance_name not in self._config_data.instances:

      raise errors.ConfigurationError("Unknown instance '%s'" %

                                      instance_name)

    instance = self._config_data.instances[instance_name]

    instance.status = "up"

    self._WriteConfig()

  def RemoveInstance(self, instance_name):

    """Remove the instance from the configuration.

    """

    self._OpenConfig()

    if instance_name not in self._config_data.instances:

      raise errors.ConfigurationError("Unknown instance '%s'" % instance_name)

    del self._config_data.instances[instance_name]

    self._WriteConfig()

  def RenameInstance(self, old_name, new_name):

    """Rename an instance.

    This needs to be done in ConfigWriter and not by RemoveInstance

    combined with AddInstance as only we can guarantee an atomic

    rename.

    """

    self._OpenConfig()

    if old_name not in self._config_data.instances:

      raise errors.ConfigurationError("Unknown instance '%s'" % old_name)

    inst = self._config_data.instances[old_name]

    del self._config_data.instances[old_name]

    inst.name = new_name

    self._config_data.instances[inst.name] = inst

    self._WriteConfig()

  def MarkInstanceDown(self, instance_name):

    """Mark the status of an instance to down in the configuration.

    """

    self._OpenConfig()

    if instance_name not in self._config_data.instances:

      raise errors.ConfigurationError("Unknown instance '%s'" % instance_name)

    instance = self._config_data.instances[instance_name]

    instance.status = "down"

    self._WriteConfig()

  def GetInstanceList(self):

    """Get the list of instances.

    Returns:

      array of instances, ex. ['instance2.example.com','instance1.example.com']

      these contains all the instances, also the ones in Admin_down state

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data.instances.keys()

  def ExpandInstanceName(self, short_name):

    """Attempt to expand an incomplete instance name.

    """

    self._OpenConfig()

    self._ReleaseLock()

    return utils.MatchNameComponent(short_name,

                                    self._config_data.instances.keys())

  def GetInstanceInfo(self, instance_name):

    """Returns informations about an instance.

    It takes the information from the configuration file. Other informations of

    an instance are taken from the live systems.

    Args:

      instance: name of the instance, ex instance1.example.com

    Returns:

      the instance object

    """

    self._OpenConfig()

    self._ReleaseLock()

    if instance_name not in self._config_data.instances:

      return None

    return self._config_data.instances[instance_name]

  def AddNode(self, node):

    """Add a node to the configuration.

    Args:

      node: an object.Node instance

    """

    self._OpenConfig()

    self._config_data.nodes[node.name] = node

    self._WriteConfig()

  def RemoveNode(self, node_name):

    """Remove a node from the configuration.

    """

    self._OpenConfig()

    if node_name not in self._config_data.nodes:

      raise errors.ConfigurationError("Unknown node '%s'" % node_name)

    del self._config_data.nodes[node_name]

    self._WriteConfig()

  def ExpandNodeName(self, short_name):

    """Attempt to expand an incomplete instance name.

    """

    self._OpenConfig()

    self._ReleaseLock()

    return utils.MatchNameComponent(short_name,

                                    self._config_data.nodes.keys())

  def GetNodeInfo(self, node_name):

    """Get the configuration of a node, as stored in the config.

    Args: node: nodename (tuple) of the node

    Returns: the node object

    """

    self._OpenConfig()

    self._ReleaseLock()

    if node_name not in self._config_data.nodes:

      return None

    return self._config_data.nodes[node_name]

  def GetNodeList(self):

    """Return the list of nodes which are in the configuration.

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data.nodes.keys()

  def DumpConfig(self):

    """Return the entire configuration of the cluster.

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data

  def _BumpSerialNo(self):

    """Bump up the serial number of the config.

    """

    self._config_data.cluster.serial_no += 1

  def _OpenConfig(self):

    """Read the config data from disk.

    In case we already have configuration data and the config file has

    the same mtime as when we read it, we skip the parsing of the

    file, since de-serialisation could be slow.

    """

    try:

      st = os.stat(self._cfg_file)

    except OSError, err:

      raise errors.ConfigurationError("Can't stat config file: %s" % err)

    if (self._config_data is not None and

        self._config_time is not None and

        self._config_time == st.st_mtime and

        self._config_size == st.st_size and

        self._config_inode == st.st_ino):

      # data is current, so skip loading of config file

      return

    f = open(self._cfg_file, 'r')

    try:

      try:

        data = objects.ConfigObject.Load(f)

      except Exception, err:

        raise errors.ConfigurationError(err)

    finally:

      f.close()

    if (not hasattr(data, 'cluster') or

        not hasattr(data.cluster, 'config_version')):

      raise errors.ConfigurationError("Incomplete configuration"

                                      " (missing cluster.config_version)")

    if data.cluster.config_version != constants.CONFIG_VERSION:

      raise errors.ConfigurationError("Cluster configuration version"

                                      " mismatch, got %s instead of %s" %

                                      (data.cluster.config_version,

                                       constants.CONFIG_VERSION))

    self._config_data = data

    self._config_time = st.st_mtime

    self._config_size = st.st_size

    self._config_inode = st.st_ino

  def _ReleaseLock(self):

    """xxxx

    """

  def _DistributeConfig(self):

    """Distribute the configuration to the other nodes.

    Currently, this only copies the configuration file. In the future,

    it could be used to encapsulate the 2/3-phase update mechanism.

    """

    if self._offline:

      return True

    bad = False

    nodelist = self.GetNodeList()

    myhostname = self._my_hostname

    tgt_list = []

    for node in nodelist:

      nodeinfo = self.GetNodeInfo(node)

      if nodeinfo.name == myhostname:

        continue

      tgt_list.append(node)

    result = rpc.call_upload_file(tgt_list, self._cfg_file)

    for node in tgt_list:

      if not result[node]:

        logger.Error("copy of file %s to node %s failed" %

                     (self._cfg_file, node))

        bad = True

    return not bad

  def _WriteConfig(self, destination=None):

    """Write the configuration data to persistent storage.

    """

    if destination is None:

      destination = self._cfg_file

    self._BumpSerialNo()

    dir_name, file_name = os.path.split(destination)

    fd, name = tempfile.mkstemp('.newconfig', file_name, dir_name)

    f = os.fdopen(fd, 'w')

    try:

      self._config_data.Dump(f)

      os.fsync(f.fileno())

    finally:

      f.close()

    # we don't need to do os.close(fd) as f.close() did it

    os.rename(name, destination)

    # re-set our cache as not to re-read the config file

    try:

      st = os.stat(destination)

    except OSError, err:

      raise errors.ConfigurationError("Can't stat config file: %s" % err)

    self._config_time = st.st_mtime

    self._config_size = st.st_size

    self._config_inode = st.st_ino

    # and redistribute the config file

    self._DistributeConfig()

  def InitConfig(self, node, primary_ip, secondary_ip,

                 hostkeypub, mac_prefix, vg_name, def_bridge):

    """Create the initial cluster configuration.

    It will contain the current node, which will also be the master

    node, and no instances or operating systmes.

    Args:

      node: the nodename of the initial node

      primary_ip: the IP address of the current host

      secondary_ip: the secondary IP of the current host or None

      hostkeypub: the public hostkey of this host

    """

    hu_port = constants.FIRST_DRBD_PORT - 1

    globalconfig = objects.Cluster(config_version=constants.CONFIG_VERSION,

                                   serial_no=1,

                                   rsahostkeypub=hostkeypub,

                                   highest_used_port=hu_port,

                                   mac_prefix=mac_prefix,

                                   volume_group_name=vg_name,

                                   default_bridge=def_bridge,

                                   tcpudp_port_pool=set())

    if secondary_ip is None:

      secondary_ip = primary_ip

    nodeconfig = objects.Node(name=node, primary_ip=primary_ip,

                              secondary_ip=secondary_ip)

    self._config_data = objects.ConfigData(nodes={node: nodeconfig},

                                           instances={},

                                           cluster=globalconfig)

    self._WriteConfig()

  def GetVGName(self):

    """Return the volume group name.

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data.cluster.volume_group_name

  def GetDefBridge(self):

    """Return the default bridge.

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data.cluster.default_bridge

  def GetMACPrefix(self):

    """Return the mac prefix.

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data.cluster.mac_prefix

  def GetClusterInfo(self):

    """Returns informations about the cluster

    Returns:

      the cluster object

    """

    self._OpenConfig()

    self._ReleaseLock()

    return self._config_data.cluster

  def Update(self, target):

    """Notify function to be called after updates.

    This function must be called when an object (as returned by

    GetInstanceInfo, GetNodeInfo, GetCluster) has been updated and the

    caller wants the modifications saved to the backing store. Note

    that all modified objects will be saved, but the target argument

    is the one the caller wants to ensure that it's saved.

    """

    if self._config_data is None:

      raise errors.ProgrammerError("Configuration file not read,"

                                   " cannot save.")

    if isinstance(target, objects.Cluster):

      test = target == self._config_data.cluster

    elif isinstance(target, objects.Node):

      test = target in self._config_data.nodes.values()

    elif isinstance(target, objects.Instance):

      test = target in self._config_data.instances.values()

    else:

      raise errors.ProgrammerError("Invalid object type (%s) passed to"

                                   " ConfigWriter.Update" % type(target))

    if not test:

      raise errors.ConfigurationError("Configuration updated since object"

                                      " has been read or unknown object")

    self._WriteConfig()