root / lib / objects.py @ a8083063
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#!/usr/bin/python
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#
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# Copyright (C) 2006, 2007 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Transportable objects for Ganeti.
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This module provides small, mostly data-only objects which are safe to
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pass to and from external parties.
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"""
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import cPickle |
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from cStringIO import StringIO |
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import ConfigParser |
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from ganeti import errors |
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__all__ = ["ConfigObject", "ConfigData", "NIC", "Disk", "Instance", |
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"OS", "Node", "Cluster"] |
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class ConfigObject(object): |
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"""A generic config object.
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It has the following properties:
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- provides somewhat safe recursive unpickling and pickling for its classes
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- unset attributes which are defined in slots are always returned
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as None instead of raising an error
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Classes derived from this must always declare __slots__ (we use many
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config objects and the memory reduction is useful.
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"""
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__slots__ = [] |
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def __init__(self, **kwargs): |
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for i in kwargs: |
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setattr(self, i, kwargs[i]) |
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def __getattr__(self, name): |
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if name not in self.__slots__: |
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raise AttributeError, ("Invalid object attribute %s.%s" % |
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(type(self).__name__, name)) |
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return None |
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def __getstate__(self): |
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state = {} |
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for name in self.__slots__: |
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if hasattr(self, name): |
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state[name] = getattr(self, name) |
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return state
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def __setstate__(self, state): |
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for name in state: |
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if name in self.__slots__: |
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setattr(self, name, state[name]) |
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@staticmethod
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def FindGlobal(module, name): |
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"""Function filtering the allowed classes to be un-pickled.
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Currently, we only allow the classes from this module which are
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derived from ConfigObject.
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"""
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# Also support the old module name (ganeti.config)
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cls = None
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if module == "ganeti.config" or module == "ganeti.objects": |
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if name == "ConfigData": |
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cls = ConfigData |
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elif name == "NIC": |
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cls = NIC |
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elif name == "Disk" or name == "BlockDev": |
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cls = Disk |
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elif name == "Instance": |
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cls = Instance |
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elif name == "OS": |
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cls = OS |
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elif name == "Node": |
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cls = Node |
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elif name == "Cluster": |
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cls = Cluster |
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if cls is None: |
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raise cPickle.UnpicklingError, ("Class %s.%s not allowed due to" |
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" security concerns" % (module, name))
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return cls
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def Dump(self, fobj): |
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"""Dump this instance to a file object.
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Note that we use the HIGHEST_PROTOCOL, as it brings benefits for
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the new classes.
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"""
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dumper = cPickle.Pickler(fobj, cPickle.HIGHEST_PROTOCOL) |
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dumper.dump(self)
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@staticmethod
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def Load(fobj): |
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"""Unpickle data from the given stream.
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This uses the `FindGlobal` function to filter the allowed classes.
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"""
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loader = cPickle.Unpickler(fobj) |
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loader.find_global = ConfigObject.FindGlobal |
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return loader.load()
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def Dumps(self): |
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"""Dump this instance and return the string representation."""
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buf = StringIO() |
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self.Dump(buf)
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return buf.getvalue()
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@staticmethod
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def Loads(data): |
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"""Load data from a string."""
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return ConfigObject.Load(StringIO(data))
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class ConfigData(ConfigObject): |
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"""Top-level config object."""
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__slots__ = ["cluster", "nodes", "instances"] |
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class NIC(ConfigObject): |
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"""Config object representing a network card."""
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__slots__ = ["mac", "ip", "bridge"] |
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class Disk(ConfigObject): |
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"""Config object representing a block device."""
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__slots__ = ["dev_type", "logical_id", "physical_id", |
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"children", "iv_name", "size"] |
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def CreateOnSecondary(self): |
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"""Test if this device needs to be created on a secondary node."""
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return self.dev_type in ("drbd", "lvm") |
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def AssembleOnSecondary(self): |
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"""Test if this device needs to be assembled on a secondary node."""
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return self.dev_type in ("drbd", "lvm") |
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def OpenOnSecondary(self): |
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"""Test if this device needs to be opened on a secondary node."""
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return self.dev_type in ("lvm",) |
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def GetNodes(self, node): |
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"""This function returns the nodes this device lives on.
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Given the node on which the parent of the device lives on (or, in
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case of a top-level device, the primary node of the devices'
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instance), this function will return a list of nodes on which this
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devices needs to (or can) be assembled.
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"""
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if self.dev_type == "lvm" or self.dev_type == "md_raid1": |
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result = [node] |
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elif self.dev_type == "drbd": |
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result = [self.logical_id[0], self.logical_id[1]] |
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if node not in result: |
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raise errors.ConfigurationError, ("DRBD device passed unknown node") |
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else:
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raise errors.ProgrammerError, "Unhandled device type %s" % self.dev_type |
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return result
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def ComputeNodeTree(self, parent_node): |
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"""Compute the node/disk tree for this disk and its children.
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This method, given the node on which the parent disk lives, will
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return the list of all (node, disk) pairs which describe the disk
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tree in the most compact way. For example, a md/drbd/lvm stack
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will be returned as (primary_node, md) and (secondary_node, drbd)
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which represents all the top-level devices on the nodes. This
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means that on the primary node we need to activate the the md (and
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recursively all its children) and on the secondary node we need to
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activate the drbd device (and its children, the two lvm volumes).
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"""
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my_nodes = self.GetNodes(parent_node)
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result = [(node, self) for node in my_nodes] |
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if not self.children: |
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# leaf device
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return result
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for node in my_nodes: |
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for child in self.children: |
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child_result = child.ComputeNodeTree(node) |
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if len(child_result) == 1: |
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# child (and all its descendants) is simple, doesn't split
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# over multiple hosts, so we don't need to describe it, our
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# own entry for this node describes it completely
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continue
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else:
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# check if child nodes differ from my nodes; note that
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# subdisk can differ from the child itself, and be instead
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# one of its descendants
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for subnode, subdisk in child_result: |
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if subnode not in my_nodes: |
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result.append((subnode, subdisk)) |
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# otherwise child is under our own node, so we ignore this
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# entry (but probably the other results in the list will
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# be different)
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return result
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class Instance(ConfigObject): |
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"""Config object representing an instance."""
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__slots__ = [ |
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"name",
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"primary_node",
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"os",
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"status",
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"memory",
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"vcpus",
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"nics",
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"disks",
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"disk_template",
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] |
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def _ComputeSecondaryNodes(self): |
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"""Compute the list of secondary nodes.
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Since the data is already there (in the drbd disks), keeping it as
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a separate normal attribute is redundant and if not properly
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synchronised can cause problems. Thus it's better to compute it
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dynamically.
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"""
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def _Helper(primary, sec_nodes, device): |
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"""Recursively computes secondary nodes given a top device."""
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if device.dev_type == 'drbd': |
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nodea, nodeb, dummy = device.logical_id |
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if nodea == primary:
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candidate = nodeb |
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else:
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candidate = nodea |
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if candidate not in sec_nodes: |
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sec_nodes.append(candidate) |
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if device.children:
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for child in device.children: |
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_Helper(primary, sec_nodes, child) |
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secondary_nodes = [] |
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for device in self.disks: |
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_Helper(self.primary_node, secondary_nodes, device)
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return tuple(secondary_nodes) |
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secondary_nodes = property(_ComputeSecondaryNodes, None, None, |
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"List of secondary nodes")
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def MapLVsByNode(self, lvmap=None, devs=None, node=None): |
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"""Provide a mapping of nodes to LVs this instance owns.
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This function figures out what logical volumes should belong on which
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nodes, recursing through a device tree.
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Args:
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lvmap: (optional) a dictionary to receive the 'node' : ['lv', ...] data.
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Returns:
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None if lvmap arg is given.
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Otherwise, { 'nodename' : ['volume1', 'volume2', ...], ... }
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"""
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if node == None: |
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node = self.primary_node
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if lvmap is None: |
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lvmap = { node : [] } |
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ret = lvmap |
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else:
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if not node in lvmap: |
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lvmap[node] = [] |
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ret = None
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if not devs: |
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devs = self.disks
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for dev in devs: |
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if dev.dev_type == "lvm": |
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lvmap[node].append(dev.logical_id[1])
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elif dev.dev_type == "drbd": |
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if dev.logical_id[0] not in lvmap: |
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lvmap[dev.logical_id[0]] = []
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if dev.logical_id[1] not in lvmap: |
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lvmap[dev.logical_id[1]] = []
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if dev.children:
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self.MapLVsByNode(lvmap, dev.children, dev.logical_id[0]) |
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self.MapLVsByNode(lvmap, dev.children, dev.logical_id[1]) |
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elif dev.children:
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self.MapLVsByNode(lvmap, dev.children, node)
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return ret
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class OS(ConfigObject): |
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"""Config object representing an operating system."""
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__slots__ = [ |
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"name",
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"path",
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"api_version",
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"create_script",
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"export_script",
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"import_script"
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] |
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class Node(ConfigObject): |
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"""Config object representing a node."""
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__slots__ = ["name", "primary_ip", "secondary_ip"] |
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class Cluster(ConfigObject): |
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"""Config object representing the cluster."""
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__slots__ = [ |
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"config_version",
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"serial_no",
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"master_node",
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"name",
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"rsahostkeypub",
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"highest_used_port",
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"mac_prefix",
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"volume_group_name",
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"default_bridge",
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] |
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class SerializableConfigParser(ConfigParser.SafeConfigParser): |
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"""Simple wrapper over ConfigParse that allows serialization.
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This class is basically ConfigParser.SafeConfigParser with two
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additional methods that allow it to serialize/unserialize to/from a
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buffer.
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"""
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def Dumps(self): |
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"""Dump this instance and return the string representation."""
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buf = StringIO() |
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self.write(buf)
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return buf.getvalue()
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@staticmethod
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def Loads(data): |
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"""Load data from a string."""
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buf = StringIO(data) |
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cfp = SerializableConfigParser() |
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cfp.readfp(buf) |
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return cfp
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