Synnefo » snf-ganeti » ganeti-local

#

#

# Copyright (C) 2013 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.

"""Utility functions for storage.

"""

from ganeti import constants

def GetDiskTemplatesOfStorageType(storage_type):

  """Given the storage type, returns a list of disk templates based on that

     storage type."""

  return [dt for dt in constants.DISK_TEMPLATES

          if constants.DISK_TEMPLATES_STORAGE_TYPE[dt] == storage_type]

def GetLvmDiskTemplates():

  """Returns all disk templates that use LVM."""

  return GetDiskTemplatesOfStorageType(constants.ST_LVM_VG)

def IsLvmEnabled(enabled_disk_templates):

  """Check whether or not any lvm-based disk templates are enabled."""

  return len(set(GetLvmDiskTemplates())

             .intersection(set(enabled_disk_templates))) != 0

def LvmGetsEnabled(enabled_disk_templates, new_enabled_disk_templates):

  """Checks whether lvm was not enabled before, but will be enabled after

     the operation.

  """

  if IsLvmEnabled(enabled_disk_templates):

    return False

  return set(GetLvmDiskTemplates()).intersection(

      set(new_enabled_disk_templates))