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#
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#
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# Copyright (C) 2006, 2007, 2008 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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"""Fake hypervisor
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"""
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import os
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import os.path
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import re
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from ganeti import utils
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from ganeti import constants
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from ganeti import errors
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from ganeti.hypervisor import hv_base
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class FakeHypervisor(hv_base.BaseHypervisor):
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  """Fake hypervisor interface.
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  This can be used for testing the ganeti code without having to have
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  a real virtualisation software installed.
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  """
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  _ROOT_DIR = constants.RUN_DIR + "/ganeti-fake-hypervisor"
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  def __init__(self):
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    hv_base.BaseHypervisor.__init__(self)
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    if not os.path.exists(self._ROOT_DIR):
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      os.mkdir(self._ROOT_DIR)
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  def ListInstances(self):
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    """Get the list of running instances.
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    """
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    return os.listdir(self._ROOT_DIR)
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  def GetInstanceInfo(self, instance_name):
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    """Get instance properties.
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    @param instance_name: the instance name
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    @return: tuple of (name, id, memory, vcpus, stat, times)
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    """
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    file_name = "%s/%s" % (self._ROOT_DIR, instance_name)
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    if not os.path.exists(file_name):
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      return None
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    try:
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      fh = open(file_name, "r")
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      try:
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        inst_id = fh.readline().strip()
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        memory = utils.TryConvert(int, fh.readline().strip())
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        vcpus = utils.TryConvert(fh.readline().strip())
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        stat = "---b-"
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        times = "0"
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        return (instance_name, inst_id, memory, vcpus, stat, times)
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      finally:
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        fh.close()
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    except IOError, err:
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      raise errors.HypervisorError("Failed to list instance %s: %s" %
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                                   (instance_name, err))
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  def GetAllInstancesInfo(self):
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    """Get properties of all instances.
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    @return: list of tuples (name, id, memory, vcpus, stat, times)
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    """
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    data = []
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    for file_name in os.listdir(self._ROOT_DIR):
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      try:
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        fh = open(self._ROOT_DIR+"/"+file_name, "r")
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        inst_id = "-1"
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        memory = 0
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        vcpus = 1
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        stat = "-----"
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        times = "-1"
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        try:
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          inst_id = fh.readline().strip()
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          memory = utils.TryConvert(int, fh.readline().strip())
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          vcpus = utils.TryConvert(int, fh.readline().strip())
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          stat = "---b-"
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          times = "0"
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        finally:
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          fh.close()
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        data.append((file_name, inst_id, memory, vcpus, stat, times))
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      except IOError, err:
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        raise errors.HypervisorError("Failed to list instances: %s" % err)
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    return data
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  def StartInstance(self, instance, block_devices):
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    """Start an instance.
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    For the fake hypervisor, it just creates a file in the base dir,
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    creating an exception if it already exists. We don't actually
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    handle race conditions properly, since these are *FAKE* instances.
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    """
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    file_name = self._ROOT_DIR + "/%s" % instance.name
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    if os.path.exists(file_name):
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      raise errors.HypervisorError("Failed to start instance %s: %s" %
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                                   (instance.name, "already running"))
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    try:
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      fh = file(file_name, "w")
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      try:
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        fh.write("0\n%d\n%d\n" %
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                 (instance.beparams[constants.BE_MEMORY],
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                  instance.beparams[constants.BE_VCPUS]))
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      finally:
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        fh.close()
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    except IOError, err:
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      raise errors.HypervisorError("Failed to start instance %s: %s" %
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                                   (instance.name, err))
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  def StopInstance(self, instance, force=False):
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    """Stop an instance.
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    For the fake hypervisor, this just removes the file in the base
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    dir, if it exist, otherwise we raise an exception.
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    """
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    file_name = self._ROOT_DIR + "/%s" % instance.name
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    if not os.path.exists(file_name):
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      raise errors.HypervisorError("Failed to stop instance %s: %s" %
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                                   (instance.name, "not running"))
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    utils.RemoveFile(file_name)
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  def RebootInstance(self, instance):
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    """Reboot an instance.
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    For the fake hypervisor, this does nothing.
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    """
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    return
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  def GetNodeInfo(self):
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    """Return information about the node.
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    This is just a wrapper over the base GetLinuxNodeInfo method.
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    @return: a dict with the following keys (values in MiB):
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          - memory_total: the total memory size on the node
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          - memory_free: the available memory on the node for instances
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          - memory_dom0: the memory used by the node itself, if available
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    """
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    result = self.GetLinuxNodeInfo()
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    # substract running instances
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    all_instances = self.GetAllInstancesInfo()
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    result['memory_free'] -= min(result['memory_free'],
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                                 sum([row[2] for row in all_instances]))
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    return result
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  @classmethod
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  def GetShellCommandForConsole(cls, instance, hvparams, beparams):
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    """Return a command for connecting to the console of an instance.
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    """
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    return "echo Console not available for fake hypervisor"
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  def Verify(self):
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    """Verify the hypervisor.
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    For the fake hypervisor, it just checks the existence of the base
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    dir.
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    """
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    if not os.path.exists(self._ROOT_DIR):
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      return "The required directory '%s' does not exist." % self._ROOT_DIR
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  @classmethod
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  def PowercycleNode(cls):
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    """Fake hypervisor powercycle, just a wrapper over Linux powercycle.
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    """
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    cls.LinuxPowercycle()