root / lib / utils / storage.py @ 4e6cfd11
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# Copyright (C) 2013 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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"""Utility functions for storage.
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"""
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import logging |
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from ganeti import constants |
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def GetDiskTemplatesOfStorageType(storage_type): |
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"""Given the storage type, returns a list of disk templates based on that
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storage type."""
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return [dt for dt in constants.DISK_TEMPLATES |
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if constants.MAP_DISK_TEMPLATE_STORAGE_TYPE[dt] == storage_type]
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def GetLvmDiskTemplates(): |
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"""Returns all disk templates that use LVM."""
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return GetDiskTemplatesOfStorageType(constants.ST_LVM_VG)
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def IsDiskTemplateEnabled(disk_template, enabled_disk_templates): |
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"""Checks if a particular disk template is enabled.
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"""
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return disk_template in enabled_disk_templates |
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def IsFileStorageEnabled(enabled_disk_templates): |
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"""Checks if file storage is enabled.
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"""
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return IsDiskTemplateEnabled(constants.DT_FILE, enabled_disk_templates)
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def IsSharedFileStorageEnabled(enabled_disk_templates): |
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"""Checks if shared file storage is enabled.
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"""
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return IsDiskTemplateEnabled(constants.DT_SHARED_FILE, enabled_disk_templates)
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def IsLvmEnabled(enabled_disk_templates): |
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"""Check whether or not any lvm-based disk templates are enabled."""
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return len(set(GetLvmDiskTemplates()) |
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.intersection(set(enabled_disk_templates))) != 0 |
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def LvmGetsEnabled(enabled_disk_templates, new_enabled_disk_templates): |
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"""Checks whether lvm was not enabled before, but will be enabled after
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the operation.
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"""
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if IsLvmEnabled(enabled_disk_templates):
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return False |
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return set(GetLvmDiskTemplates()).intersection( |
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set(new_enabled_disk_templates))
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def _GetDefaultStorageUnitForDiskTemplate(cfg, disk_template): |
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"""Retrieves the identifier of the default storage entity for the given
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storage type.
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@type cfg: C{objects.ConfigData}
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@param cfg: the configuration data
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@type disk_template: string
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@param disk_template: a disk template, for example 'drbd'
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@rtype: string
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@return: identifier for a storage unit, for example the vg_name for lvm
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storage
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"""
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storage_type = constants.MAP_DISK_TEMPLATE_STORAGE_TYPE[disk_template] |
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cluster = cfg.GetClusterInfo() |
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if disk_template in GetLvmDiskTemplates(): |
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return (storage_type, cfg.GetVGName())
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elif disk_template == constants.DT_FILE:
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return (storage_type, cluster.file_storage_dir)
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elif disk_template == constants.DT_SHARED_FILE:
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return (storage_type, cluster.shared_file_storage_dir)
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else:
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return (storage_type, None) |
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def _GetDefaultStorageUnitForSpindles(cfg): |
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"""Creates a 'spindle' storage unit, by retrieving the volume group
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name and associating it to the lvm-pv storage type.
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@rtype: (string, string)
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@return: tuple (storage_type, storage_key), where storage type is
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'lvm-pv' and storage_key the name of the default volume group
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"""
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return (constants.ST_LVM_PV, cfg.GetVGName())
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def GetStorageUnitsOfCluster(cfg, include_spindles=False): |
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"""Examines the cluster's configuration and returns a list of storage
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units and their storage keys, ordered by the order in which they
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are enabled.
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@type cfg: L{config.ConfigWriter}
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@param cfg: Cluster configuration
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@type include_spindles: boolean
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@param include_spindles: flag to include an extra storage unit for physical
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volumes
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@rtype: list of tuples (string, string)
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@return: list of storage units, each storage unit being a tuple of
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(storage_type, storage_key); storage_type is in
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C{constants.STORAGE_TYPES} and the storage_key a string to
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identify an entity of that storage type, for example a volume group
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name for LVM storage or a file for file storage.
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"""
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cluster_config = cfg.GetClusterInfo() |
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storage_units = [] |
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for disk_template in cluster_config.enabled_disk_templates: |
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if constants.MAP_DISK_TEMPLATE_STORAGE_TYPE[disk_template]\
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in constants.STS_REPORT:
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storage_units.append( |
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_GetDefaultStorageUnitForDiskTemplate(cfg, disk_template)) |
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if include_spindles:
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included_storage_types = set([st for (st, _) in storage_units]) |
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if not constants.ST_LVM_PV in included_storage_types: |
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storage_units.append( |
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_GetDefaultStorageUnitForSpindles(cfg)) |
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return storage_units
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def LookupSpaceInfoByStorageType(storage_space_info, storage_type): |
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"""Looks up the storage space info for a given storage type.
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Note that this lookup can be ambiguous if storage space reporting for several
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units of the same storage type was requested. This function is only supposed
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to be used for legacy code in situations where it actually is unambiguous.
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@type storage_space_info: list of dicts
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@param storage_space_info: result of C{GetNodeInfo}
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@type storage_type: string
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@param storage_type: a storage type, which is included in the storage_units
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list
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@rtype: tuple
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@return: returns the element of storage_space_info that matches the given
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storage type
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"""
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result = None
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for unit_info in storage_space_info: |
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if unit_info["type"] == storage_type: |
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if result is None: |
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result = unit_info |
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else:
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# There is more than one storage type in the query, log a warning
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logging.warning("Storage space information requested for"
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" ambiguous storage type '%s'.", storage_type)
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return result
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