Source Code for Module ganeti.cmdlib.instance_helpervm

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 29   
 30   
 31  """Functions for running helper virtual machines to perform tasks on instances. 
 32   
 33  """ 
 34   
 35  import contextlib 
 36   
 37  from ganeti import constants 
 38  from ganeti import errors 
 39  from ganeti.utils import retry 
 40   
 41  from ganeti.cmdlib.common import IsInstanceRunning, DetermineImageSize 
 42  from ganeti.cmdlib.instance_storage import StartInstanceDisks, \ 
 43    TemporaryDisk, ImageDisks 
 44   
 45   
 46  @contextlib.contextmanager 
 47 -def HelperVM(lu, instance, vm_image, startup_timeout, vm_timeout, 
 48               log_prefix=None, feedback_fn=None): 
 49    """Runs a given helper VM for a given instance. 
 50   
 51    @type lu: L{LogicalUnit} 
 52    @param lu: the lu on whose behalf we execute 
 53    @type instance: L{objects.Instance} 
 54    @param instance: the instance definition 
 55    @type vm_image: string 
 56    @param vm_image: the name of the helper VM image to dump on a temporary disk 
 57    @type startup_timeout: int 
 58    @param startup_timeout: how long to wait for the helper VM to start up 
 59    @type vm_timeout: int 
 60    @param vm_timeout: how long to wait for the helper VM to finish its work 
 61    @type log_prefix: string 
 62    @param log_prefix: a prefix for all log messages 
 63    @type feedback_fn: function 
 64    @param feedback_fn: Function used to log progress 
 65   
 66    """ 
 67    if log_prefix: 
 68      add_prefix = lambda msg: "%s: %s" % (log_prefix, msg) 
 69    else: 
 70      add_prefix = lambda msg: msg 
 71   
 72    if feedback_fn is not None: 
 73      log_feedback = lambda msg: feedback_fn(add_prefix(msg)) 
 74    else: 
 75      log_feedback = lambda _: None 
 76   
 77    try: 
 78      disk_size = DetermineImageSize(lu, vm_image, instance.primary_node) 
 79    except errors.OpExecError, err: 
 80      raise errors.OpExecError("Could not create temporary disk: %s", err) 
 81   
 82    with TemporaryDisk(lu, 
 83                       instance, 
 84                       [(constants.DT_PLAIN, constants.DISK_RDWR, disk_size)], 
 85                       log_feedback): 
 86      log_feedback("Activating helper VM's temporary disks") 
 87      StartInstanceDisks(lu, instance, False) 
 88   
 89      log_feedback("Imaging temporary disks with image %s" % (vm_image, )) 
 90      ImageDisks(lu, instance, vm_image) 
 91   
 92      log_feedback("Starting helper VM") 
 93      result = lu.rpc.call_instance_start(instance.primary_node, 
 94                                          (instance, [], []), 
 95                                          False, lu.op.reason) 
 96      result.Raise(add_prefix("Could not start helper VM with image %s" % 
 97                              (vm_image, ))) 
 98   
 99      # First wait for the instance to start up 
100      running_check = lambda: IsInstanceRunning(lu, instance, prereq=False) 
101      instance_up = retry.SimpleRetry(True, running_check, 5.0, 
102                                      startup_timeout) 
103      if not instance_up: 
104        raise errors.OpExecError(add_prefix("Could not boot instance using" 
105                                            " image %s" % (vm_image, ))) 
106   
107      log_feedback("Helper VM is up") 
108   
109      def cleanup(): 
110        log_feedback("Waiting for helper VM to finish") 
111   
112        # Then for it to be finished, detected by its shutdown 
113        instance_up = retry.SimpleRetry(False, running_check, 20.0, vm_timeout) 
114        if instance_up: 
115          lu.LogWarning(add_prefix("Helper VM has not finished within the" 
116                                   " timeout; shutting it down forcibly")) 
117          return \ 
118            lu.rpc.call_instance_shutdown(instance.primary_node, 
119                                          instance, 
120                                          constants.DEFAULT_SHUTDOWN_TIMEOUT, 
121                                          lu.op.reason) 
122        else: 
123          return None 
124   
125      # Run the inner block and handle possible errors 
126      try: 
127        yield 
128      except Exception: 
129        # if the cleanup failed for some reason, log it and just re-raise 
130        result = cleanup() 
131        if result: 
132          result.Warn(add_prefix("Could not shut down helper VM with image" 
133                                 " %s within timeout" % (vm_image, ))) 
134          log_feedback("Error running helper VM with image %s" % 
135                       (vm_image, )) 
136        raise 
137      else: 
138        result = cleanup() 
139        # if the cleanup failed for some reason, throw an exception 
140        if result: 
141          result.Raise(add_prefix("Could not shut down helper VM with image %s" 
142                                  " within timeout" % (vm_image, ))) 
143          raise errors.OpExecError("Error running helper VM with image %s" % 
144                                   (vm_image, )) 
145   
146    log_feedback("Helper VM execution completed") 
147   
148   
149 -def RunWithHelperVM(lu, instance, vm_image, startup_timeout, vm_timeout, 
150                      log_prefix=None, feedback_fn=None): 
151    """Runs a given helper VM for a given instance. 
152   
153    @type lu: L{LogicalUnit} 
154    @param lu: the lu on whose behalf we execute 
155    @type instance: L{objects.Instance} 
156    @param instance: the instance definition 
157    @type vm_image: string 
158    @param vm_image: the name of the helper VM image to dump on a temporary disk 
159    @type startup_timeout: int 
160    @param startup_timeout: how long to wait for the helper VM to start up 
161    @type vm_timeout: int 
162    @param vm_timeout: how long to wait for the helper VM to finish its work 
163    @type log_prefix: string 
164    @param log_prefix: a prefix for all log messages 
165    @type feedback_fn: function 
166    @param feedback_fn: Function used to log progress 
167   
168   
169    """ 
170    with HelperVM(lu, instance, vm_image, startup_timeout, vm_timeout, 
171                  log_prefix=log_prefix, feedback_fn=feedback_fn): 
172      pass 
173