code.grnet.gr Git - archipelago/blob - xseg/tools/ext_scripts/vlmc

1 #!/usr/bin/env python

2 #

4 #

5 # This program is free software; you can redistribute it and/or modify

6 # it under the terms of the GNU General Public License as published by

7 # the Free Software Foundation; either version 2 of the License, or

8 # (at your option) any later version.

9 #

10 # This program is distributed in the hope that it will be useful, but

11 # WITHOUT ANY WARRANTY; without even the implied warranty of

12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

13 # General Public License for more details.

14 #

15 # You should have received a copy of the GNU General Public License

16 # along with this program; if not, write to the Free Software

17 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

18 # 02110-1301, USA.

20 """ vlmc provider wrapper-script for ganeti extstorage disk template

22 The script takes it's input from environment variables. Specifically the

23 following variables should be present:

25 - VOL_NAME: The name of the new Image file

26 - VOL_SIZE: The size of the new Image (in megabytes)

28 The following variables are optional:

30 - EXTP_ORIGIN: The name of the Image file to snapshot

32 The code branches to the correct function, depending on the name (sys.argv[0])

33 of the executed script (attach, create, etc).

35 Returns O after successfull completion, 1 on failure

37 """

39 import os

40 import sys

42 from ganeti import utils

45 def ReadEnv():

46 """Read the enviromental variables

47 """

49 name = os.getenv("VOL_NAME")

50 if name is None:

51 sys.stderr.write('The environment variable VOL_NAME is missing.\n')

52 return None

54 size = os.getenv("VOL_SIZE")

55 if size is None:

56 sys.stderr.write('The environment variable VOL_SIZE is missing.\n')

57 return None

59 origin = os.getenv("EXTP_ORIGIN")

61 return (name, size, origin)

63 def create(env):

64 """Create a new vlmc Image

65 """

66 sys.stderr.write('Creation started...\n')

68 name, size, origin = env

70 cmd = ["vlmc", "create", "%s" % name, "--size", "%s" % size]

71 if origin:

72 cmd.extend(["--snap", origin])

74 sys.stderr.write('Before RunCmd')

75 result = utils.RunCmd(cmd)

76 sys.stderr.write('After RunCmd')

78 if result.failed:

79 sys.stderr.write('vlmc creation failed (%s): %s\n' %

80 (result.fail_reason, result.output))

81 return 1

83 return 0

85 def _ParseVlmcShowmappedOutput(output, volume_name):

86 """Parse the output of `vlmc showmapped'.

88 This method parses the output of `vlmc showmapped' and returns

89 the vlmc block device path (e.g. /dev/xsegbd0) that matches the

90 given vlmc volume.

92 """

93 allfields = 5

94 volumefield = 2

95 devicefield = 4

97 field_sep = "\t"

99 lines = output.splitlines()

100 splitted_lines = map(lambda l: l.split(field_sep), lines)

101

102 # Check empty output.

103 if not splitted_lines:

104 sys.stderr.write("vlmc showmapped returned empty output")

105 sys.exit(1)

106

107 # Check showmapped header line, to determine number of fields.

108 field_cnt = len(splitted_lines[0])

109 if field_cnt != allfields:

110 sys.stderr.write("Cannot parse vlmc showmapped output because its format"

111 " seems to have changed; expected %s fields, found %s",

112 allfields, field_cnt)

113 sys.exit(1)

114

115 matched_lines = \

116 filter(lambda l: len(l) == allfields and l[volumefield] == volume_name,

117 splitted_lines)

118

119 if len(matched_lines) > 1:

120 sys.stderr.write("The vlmc volume %s is mapped more than once."

121 " This shouldn't happen, try to unmap the extra"

122 " devices manually.", volume_name)

123 sys.exit(1)

124

125 if matched_lines:

126 # vlmc block device found. Return it.

127 dev = matched_lines[0][devicefield]

128 return dev

129

130 # The given volume is not mapped.

131 return None

132

133 def attach(env):

134 """Map an existing vlmc Image to a block device

135

136 This function maps an existing vlmc Image to a block device

137 e.g. /dev/xsegbd{X} and returns the device path. If the mapping

138 already exists, it returns the corresponding device path.

139 """

140

141 name, _, _ = env

142

143 # Check if the mapping already exists

144 cmd = ["vlmc", "showmapped"]

145 result = utils.RunCmd(cmd)

146 if result.failed:

147 sys.stderr.write("vlmc showmapped failed (%s): %s" %

148 (result.fail_reason, result.output))

149 return 1

150

151 dev = _ParseVlmcShowmappedOutput(result.output, name)

152 if dev:

153 # The mapping exists. Return it.

154 return dev

155

156 # The mapping doesn't exist. Create it.

157 map_cmd = ["vlmc", "map", name]

158 result = utils.RunCmd(map_cmd)

159 if result.failed:

160 sys.stderr.write("vlmc map failed (%s): %s",

161 result.fail_reason, result.output)

162 return 1

163

164 # Find the corresponding vlmc device.

165 showmap_cmd = ["vlmc", "showmapped"]

166 result = utils.RunCmd(showmap_cmd)

167 if result.failed:

168 sys.stderr.write("vlmc map succeeded, but showmapped failed (%s): %s",

169 result.fail_reason, result.output)

170 return 1

171

172 dev = self._ParseRbdShowmappedOutput(result.output, name)

173

174 if not dev:

175 sys.stderr.write("vlmc map succeeded, but could not find the vlmc block"

176 " device in output of showmapped, for volume: %s", name)

177

178 # The device was successfully mapped. Return it.

179 return dev

180

181 def detach(env):

182 """Unmap a vlmc device from the Image it is mapped to

183

184 This function unmaps an vlmc device from the Image it is mapped to.

185 It is idempotent if the mapping doesn't exist at all.

186 """

187 name, _, _ = env

188

189 # Check if the mapping already exists

190 cmd = ["vlmc", "showmapped"]

191 result = utils.RunCmd(cmd)

192 if result.failed:

193 sys.stderr.write("vlmc showmapped failed (%s): %s" %

194 (result.fail_reason, result.output))

195 return 1

196

197 dev = _ParseVlmcShowmappedOutput(result.output, name)

198

199 if dev:

200 # The mapping exists. Unmap the vlmc device.

201 unmap_cmd = ["vlmc", "unmap", "%s" % dev]

202 result = utils.RunCmd(unmap_cmd)

203 if result.failed:

204 sys.stderr.write("vlmc unmap failed (%s): %s",

205 result.fail_reason, result.output)

206

207 return 0

208

209 def grow(env):

210 """Grow an existing vlmc Image

211 """

212 name, size, _ = env

213

214 cmd = ["vlmc", "resize", "%s" % name, "--size", "%s" % size]

215

216 result = utils.RunCmd(cmd)

217 if result.failed:

218 sys.stderr.write('vlmc resize failed (%s): %s\n' %

219 (result.fail_reason, result.output))

220 return 1

221

222 return 0

223

224 def remove(env):

225 """ Delete a vlmc Image

226 """

227

228 name, _, _ = env

229

230 cmd = ["vlmc", "rm", "%s" % name]

231

232 result = utils.RunCmd(cmd)

233 if result.failed:

234 sys.stderr.write("Can't remove Image %s from cluster with vlmc rm: "

235 "%s - %s" %

236 (name, result.fail_reason, result.output))

237 return 1

238

239 return 0

240

241 def verify(env):

242 return 0

243

244 def main():

245 env = ReadEnv()

246 if env is None:

247 sys.stderr.write("Wrong environment. Aborting...\n")

248 return 1

249

250 try:

251 return {

252 'attach': attach(env),

253 'create': create(env),

254 'detach': detach(env),

255 'grow' : grow(env),

256 'remove': remove(env),

257 'verify': verify(env),

258 }[os.path.basename(sys.argv[0])]

259 except:

260 sys.stderr.write("Op not supported")

261 return 1

262

263 if __name__ == "__main__":

264 sys.exit(main())