HP ProLiant DL380G5-WSS 3.7.0 HP StorageWorks HP Scalable NAS File Serving Sof - Page 347

Recovery scripts, Start and Stop scripts

Page 347 highlights

NAS will then take the action configured for the service monitor, which is typically to fail over the virtual host associated with the monitor. When you create the custom service or device monitor for the probe script, you can set both the frequency at which the probe script should be executed and the timeout period, which is the maximum amount of time that the monitor_agent daemon will wait for the probe to complete. You can create more elaborate probe scripts as necessary. The key points are to check whether the service or device is up and then to return a corresponding exit status. The service or device monitor uses only the exit status to determine whether the probe succeeded or failed, with 0 indicating success and any other value indicating failure. Recovery scripts A Recovery script runs after a monitor probe fails. The script attempts to restore the service and prevent failover of the virtual host(s) associated with the monitor. Recovery scripts are useful if there is an automatic way to recover from a common failure mode for an application. For example, if you are monitoring an application called myservice that is normally started at boot time, but which is buggy and crashes occasionally, you could use a Recovery script to reduce the frequency of failovers. The script could contain the following line: /etc/rc.d/init.d/myservice restart When you add a recovery script to a service or device monitor, you can set a timeout period, which is the maximum amount of time that the monitor_agent daemon will wait for the Recovery script to complete. Start and Stop scripts These scripts are run when a monitor is instantiated for a service (because either the ClusterPulse daemon is starting or the configuration has changed). The scripts establish the desired start/stop activity. The Start script is run on the server where the monitor will be active. The Stop script is run on all other servers. Following are some typical uses of the Start and Stop scripts: • An application requires the ownership of a shared resource to be effective. The Start script tries to take ownership of the resource (returning non-zero if it fails to do so), and the Stop script yields ownership. Be sure that script ordering is strict, which is the default. (Script ordering is an advanced configuration option and is set on the Scripts tab.) HP Scalable NAS File Serving Software administration guide 347

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190
  • 191
  • 192
  • 193
  • 194
  • 195
  • 196
  • 197
  • 198
  • 199
  • 200
  • 201
  • 202
  • 203
  • 204
  • 205
  • 206
  • 207
  • 208
  • 209
  • 210
  • 211
  • 212
  • 213
  • 214
  • 215
  • 216
  • 217
  • 218
  • 219
  • 220
  • 221
  • 222
  • 223
  • 224
  • 225
  • 226
  • 227
  • 228
  • 229
  • 230
  • 231
  • 232
  • 233
  • 234
  • 235
  • 236
  • 237
  • 238
  • 239
  • 240
  • 241
  • 242
  • 243
  • 244
  • 245
  • 246
  • 247
  • 248
  • 249
  • 250
  • 251
  • 252
  • 253
  • 254
  • 255
  • 256
  • 257
  • 258
  • 259
  • 260
  • 261
  • 262
  • 263
  • 264
  • 265
  • 266
  • 267
  • 268
  • 269
  • 270
  • 271
  • 272
  • 273
  • 274
  • 275
  • 276
  • 277
  • 278
  • 279
  • 280
  • 281
  • 282
  • 283
  • 284
  • 285
  • 286
  • 287
  • 288
  • 289
  • 290
  • 291
  • 292
  • 293
  • 294
  • 295
  • 296
  • 297
  • 298
  • 299
  • 300
  • 301
  • 302
  • 303
  • 304
  • 305
  • 306
  • 307
  • 308
  • 309
  • 310
  • 311
  • 312
  • 313
  • 314
  • 315
  • 316
  • 317
  • 318
  • 319
  • 320
  • 321
  • 322
  • 323
  • 324
  • 325
  • 326
  • 327
  • 328
  • 329
  • 330
  • 331
  • 332
  • 333
  • 334
  • 335
  • 336
  • 337
  • 338
  • 339
  • 340
  • 341
  • 342
  • 343
  • 344
  • 345
  • 346
  • 347
  • 348
  • 349
  • 350
  • 351
  • 352
  • 353
  • 354
  • 355
  • 356
  • 357
  • 358
  • 359
  • 360
  • 361
  • 362
  • 363
  • 364
  • 365
  • 366
  • 367
  • 368
  • 369
  • 370
  • 371
  • 372
  • 373
  • 374
  • 375
  • 376
  • 377
  • 378
  • 379
  • 380
  • 381
  • 382
  • 383
  • 384
  • 385
  • 386
  • 387
  • 388
  • 389
  • 390
  • 391
  • 392
  • 393
  • 394
  • 395
  • 396
  • 397
  • 398
  • 399
  • 400
  • 401
  • 402
  • 403
  • 404
  • 405
  • 406
  • 407
  • 408
  • 409
  • 410
  • 411
  • 412
  • 413
  • 414
  • 415
  • 416
  • 417
  • 418
  • 419
  • 420
  • 421
  • 422
  • 423
  • 424
  • 425
  • 426
  • 427
  • 428
  • 429
  • 430
  • 431
  • 432
  • 433
  • 434
  • 435

NAS will then take the action configured for the service monitor, which is typically
to fail over the virtual host associated with the monitor.
When you create the custom service or device monitor for the probe script, you can
set both the frequency at which the probe script should be executed and the timeout
period, which is the maximum amount of time that the
monitor_agent
daemon
will wait for the probe to complete.
You can create more elaborate probe scripts as necessary. The key points are to
check whether the service or device is up and then to return a corresponding exit
status. The service or device monitor uses only the exit status to determine whether
the probe succeeded or failed, with 0 indicating success and any other value
indicating failure.
Recovery scripts
A Recovery script runs after a monitor probe fails. The script attempts to restore the
service and prevent failover of the virtual host(s) associated with the monitor.
Recovery scripts are useful if there is an automatic way to recover from a common
failure mode for an application. For example, if you are monitoring an application
called
myservice
that is normally started at boot time, but which is buggy and
crashes occasionally, you could use a Recovery script to reduce the frequency of
failovers. The script could contain the following line:
/etc/rc.d/init.d/myservice restart
When you add a recovery script to a service or device monitor, you can set a timeout
period, which is the maximum amount of time that the
monitor_agent
daemon
will wait for the Recovery script to complete.
Start and Stop scripts
These scripts are run when a monitor is instantiated for a service (because either the
ClusterPulse daemon is starting or the configuration has changed). The scripts establish
the desired start/stop activity. The Start script is run on the server where the monitor
will be active. The Stop script is run on all other servers.
Following are some typical uses of the Start and Stop scripts:
An application requires the ownership of a shared resource to be effective. The
Start script tries to take ownership of the resource (returning non-zero if it fails to
do so), and the Stop script yields ownership. Be sure that script ordering is strict,
which is the default. (Script ordering is an advanced configuration option and is
set on the Scripts tab.)
HP Scalable NAS File Serving Software administration guide
347