4 # Copyright (C) 2013 Google Inc.
6 # This program is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 2 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful, but
12 # WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 # General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with this program; if not, write to the Free Software
18 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 """Utility functions for storage.
27 from ganeti import constants
28 from ganeti import pathutils
31 def GetDiskTemplatesOfStorageType(storage_type):
32 """Given the storage type, returns a list of disk templates based on that
34 return [dt for dt in constants.DISK_TEMPLATES
35 if constants.DISK_TEMPLATES_STORAGE_TYPE[dt] == storage_type]
38 def GetLvmDiskTemplates():
39 """Returns all disk templates that use LVM."""
40 return GetDiskTemplatesOfStorageType(constants.ST_LVM_VG)
43 def IsDiskTemplateEnabled(disk_template, enabled_disk_templates):
44 """Checks if a particular disk template is enabled.
47 return disk_template in enabled_disk_templates
50 def IsFileStorageEnabled(enabled_disk_templates):
51 """Checks if file storage is enabled.
54 return IsDiskTemplateEnabled(constants.DT_FILE, enabled_disk_templates)
57 def IsSharedFileStorageEnabled(enabled_disk_templates):
58 """Checks if shared file storage is enabled.
61 return IsDiskTemplateEnabled(constants.DT_SHARED_FILE, enabled_disk_templates)
64 def IsLvmEnabled(enabled_disk_templates):
65 """Check whether or not any lvm-based disk templates are enabled."""
66 return len(set(GetLvmDiskTemplates())
67 .intersection(set(enabled_disk_templates))) != 0
70 def LvmGetsEnabled(enabled_disk_templates, new_enabled_disk_templates):
71 """Checks whether lvm was not enabled before, but will be enabled after
75 if IsLvmEnabled(enabled_disk_templates):
77 return set(GetLvmDiskTemplates()).intersection(
78 set(new_enabled_disk_templates))
81 def _GetDefaultStorageUnitForDiskTemplate(cfg, disk_template):
82 """Retrieves the identifier of the default storage entity for the given
85 @type disk_template: string
86 @param disk_template: a disk template, for example 'drbd'
88 @return: identifier for a storage unit, for example the vg_name for lvm
92 storage_type = constants.DISK_TEMPLATES_STORAGE_TYPE[disk_template]
93 if disk_template in GetLvmDiskTemplates():
94 return (storage_type, cfg.GetVGName())
95 # FIXME: Adjust this, once FILE_STORAGE_DIR and SHARED_FILE_STORAGE_DIR
96 # are not in autoconf anymore.
97 elif disk_template == constants.DT_FILE:
98 return (storage_type, pathutils.DEFAULT_FILE_STORAGE_DIR)
99 elif disk_template == constants.DT_SHARED_FILE:
100 return (storage_type, pathutils.DEFAULT_SHARED_FILE_STORAGE_DIR)
102 return (storage_type, None)
105 def _GetDefaultStorageUnitForSpindles(cfg):
106 """Creates a 'spindle' storage unit, by retrieving the volume group
107 name and associating it to the lvm-pv storage type.
109 @rtype: (string, string)
110 @return: tuple (storage_type, storage_key), where storage type is
111 'lvm-pv' and storage_key the name of the default volume group
114 return (constants.ST_LVM_PV, cfg.GetVGName())
117 # List of storage type for which space reporting is implemented.
118 # FIXME: Remove this, once the backend is capable to do this for all
120 _DISK_TEMPLATES_SPACE_QUERYABLE = GetLvmDiskTemplates() \
121 + GetDiskTemplatesOfStorageType(constants.ST_FILE)
124 def GetStorageUnitsOfCluster(cfg, include_spindles=False):
125 """Examines the cluster's configuration and returns a list of storage
126 units and their storage keys, ordered by the order in which they
129 @type cfg: L{config.ConfigWriter}
130 @param cfg: Cluster configuration
131 @type include_spindles: boolean
132 @param include_spindles: flag to include an extra storage unit for physical
134 @rtype: list of tuples (string, string)
135 @return: list of storage units, each storage unit being a tuple of
136 (storage_type, storage_key); storage_type is in
137 C{constants.VALID_STORAGE_TYPES} and the storage_key a string to
138 identify an entity of that storage type, for example a volume group
139 name for LVM storage or a file for file storage.
142 cluster_config = cfg.GetClusterInfo()
144 for disk_template in cluster_config.enabled_disk_templates:
145 if disk_template in _DISK_TEMPLATES_SPACE_QUERYABLE:
146 storage_units.append(
147 _GetDefaultStorageUnitForDiskTemplate(cfg, disk_template))
149 included_storage_types = set([st for (st, _) in storage_units])
150 if not constants.ST_LVM_PV in included_storage_types:
151 storage_units.append(
152 _GetDefaultStorageUnitForSpindles(cfg))
157 def LookupSpaceInfoByStorageType(storage_space_info, storage_type):
158 """Looks up the storage space info for a given storage type.
160 Note that this lookup can be ambiguous if storage space reporting for several
161 units of the same storage type was requested. This function is only supposed
162 to be used for legacy code in situations where it actually is unambiguous.
164 @type storage_space_info: list of dicts
165 @param storage_space_info: result of C{GetNodeInfo}
166 @type storage_type: string
167 @param storage_type: a storage type, which is included in the storage_units
170 @return: returns the element of storage_space_info that matches the given
175 for unit_info in storage_space_info:
176 if unit_info["type"] == storage_type:
180 # There is more than one storage type in the query, log a warning
181 logging.warning("Storage space information requested for"
182 " ambiguous storage type '%s'.", storage_type)