Source Code for Module ganeti.hypervisor.hv_chroot

  1  # 
  2  # 
  3   
  4  # Copyright (C) 2006, 2007, 2008, 2009 Google Inc. 
  5  # 
  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. 
 10  # 
 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. 
 15  # 
 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 
 19  # 02110-1301, USA. 
 20   
 21   
 22  """Chroot manager hypervisor 
 23   
 24  """ 
 25   
 26  import os 
 27  import os.path 
 28  import time 
 29  import logging 
 30   
 31  from ganeti import constants 
 32  from ganeti import errors # pylint: disable=W0611 
 33  from ganeti import utils 
 34  from ganeti import objects 
 35  from ganeti import pathutils 
 36  from ganeti.hypervisor import hv_base 
 37  from ganeti.errors import HypervisorError 
 38   
 39   
 40 -class ChrootManager(hv_base.BaseHypervisor): 
 41    """Chroot manager. 
 42   
 43    This not-really hypervisor allows ganeti to manage chroots. It has 
 44    special behaviour and requirements on the OS definition and the node 
 45    environemnt: 
 46      - the start and stop of the chroot environment are done via a 
 47        script called ganeti-chroot located in the root directory of the 
 48        first drive, which should be created by the OS definition 
 49      - this script must accept the start and stop argument and, on 
 50        shutdown, it should cleanly shutdown the daemons/processes 
 51        using the chroot 
 52      - the daemons run in chroot should only bind to the instance IP 
 53        (to which the OS create script has access via the instance name) 
 54      - since some daemons in the node could be listening on the wildcard 
 55        address, some ports might be unavailable 
 56      - the instance listing will show no memory usage 
 57      - on shutdown, the chroot manager will try to find all mountpoints 
 58        under the root dir of the instance and unmount them 
 59      - instance alive check is based on whether any process is using the chroot 
 60   
 61    """ 
 62    _ROOT_DIR = pathutils.RUN_DIR + "/chroot-hypervisor" 
 63   
 64    PARAMETERS = { 
 65      constants.HV_INIT_SCRIPT: (True, utils.IsNormAbsPath, 
 66                                 "must be an absolute normalized path", 
 67                                 None, None), 
 68      } 
 69   
 70 -  def __init__(self): 
 71      hv_base.BaseHypervisor.__init__(self) 
 72      utils.EnsureDirs([(self._ROOT_DIR, constants.RUN_DIRS_MODE)]) 
 73   
 74    @staticmethod 
 75 -  def _IsDirLive(path): 
 76      """Check if a directory looks like a live chroot. 
 77   
 78      """ 
 79      if not os.path.ismount(path): 
 80        return False 
 81      result = utils.RunCmd(["fuser", "-m", path]) 
 82      return not result.failed 
 83   
 84    @staticmethod 
 85 -  def _GetMountSubdirs(path): 
 86      """Return the list of mountpoints under a given path. 
 87   
 88      """ 
 89      result = [] 
 90      for _, mountpoint, _, _ in utils.GetMounts(): 
 91        if (mountpoint.startswith(path) and 
 92            mountpoint != path): 
 93          result.append(mountpoint) 
 94   
 95      result.sort(key=lambda x: x.count("/"), reverse=True) 
 96      return result 
 97   
 98    @classmethod 
 99 -  def _InstanceDir(cls, instance_name): 
100      """Return the root directory for an instance. 
101   
102      """ 
103      return utils.PathJoin(cls._ROOT_DIR, instance_name) 
104   
105 -  def ListInstances(self): 
106      """Get the list of running instances. 
107   
108      """ 
109      return [name for name in os.listdir(self._ROOT_DIR) 
110              if self._IsDirLive(utils.PathJoin(self._ROOT_DIR, name))] 
111   
112 -  def GetInstanceInfo(self, instance_name): 
113      """Get instance properties. 
114   
115      @type instance_name: string 
116      @param instance_name: the instance name 
117   
118      @return: (name, id, memory, vcpus, stat, times) 
119   
120      """ 
121      dir_name = self._InstanceDir(instance_name) 
122      if not self._IsDirLive(dir_name): 
123        raise HypervisorError("Instance %s is not running" % instance_name) 
124      return (instance_name, 0, 0, 0, 0, 0) 
125   
126 -  def GetAllInstancesInfo(self): 
127      """Get properties of all instances. 
128   
129      @return: [(name, id, memory, vcpus, stat, times),...] 
130   
131      """ 
132      data = [] 
133      for file_name in os.listdir(self._ROOT_DIR): 
134        path = utils.PathJoin(self._ROOT_DIR, file_name) 
135        if self._IsDirLive(path): 
136          data.append((file_name, 0, 0, 0, 0, 0)) 
137      return data 
138   
139 -  def StartInstance(self, instance, block_devices, startup_paused): 
140      """Start an instance. 
141   
142      For the chroot manager, we try to mount the block device and 
143      execute '/ganeti-chroot start'. 
144   
145      """ 
146      root_dir = self._InstanceDir(instance.name) 
147      if not os.path.exists(root_dir): 
148        try: 
149          os.mkdir(root_dir) 
150        except IOError, err: 
151          raise HypervisorError("Failed to start instance %s: %s" % 
152                                (instance.name, err)) 
153        if not os.path.isdir(root_dir): 
154          raise HypervisorError("Needed path %s is not a directory" % root_dir) 
155   
156      if not os.path.ismount(root_dir): 
157        if not block_devices: 
158          raise HypervisorError("The chroot manager needs at least one disk") 
159   
160        sda_dev_path = block_devices[0][1] 
161        result = utils.RunCmd(["mount", sda_dev_path, root_dir]) 
162        if result.failed: 
163          raise HypervisorError("Can't mount the chroot dir: %s" % result.output) 
164      init_script = instance.hvparams[constants.HV_INIT_SCRIPT] 
165      result = utils.RunCmd(["chroot", root_dir, init_script, "start"]) 
166      if result.failed: 
167        raise HypervisorError("Can't run the chroot start script: %s" % 
168                              result.output) 
169   
170 -  def StopInstance(self, instance, force=False, retry=False, name=None): 
171      """Stop an instance. 
172   
173      This method has complicated cleanup tests, as we must: 
174        - try to kill all leftover processes 
175        - try to unmount any additional sub-mountpoints 
176        - finally unmount the instance dir 
177   
178      """ 
179      if name is None: 
180        name = instance.name 
181   
182      root_dir = self._InstanceDir(name) 
183      if not os.path.exists(root_dir) or not self._IsDirLive(root_dir): 
184        return 
185   
186      # Run the chroot stop script only once 
187      if not retry and not force: 
188        result = utils.RunCmd(["chroot", root_dir, "/ganeti-chroot", "stop"]) 
189        if result.failed: 
190          raise HypervisorError("Can't run the chroot stop script: %s" % 
191                                result.output) 
192   
193      if not force: 
194        utils.RunCmd(["fuser", "-k", "-TERM", "-m", root_dir]) 
195      else: 
196        utils.RunCmd(["fuser", "-k", "-KILL", "-m", root_dir]) 
197        # 2 seconds at most should be enough for KILL to take action 
198        time.sleep(2) 
199   
200      if self._IsDirLive(root_dir): 
201        if force: 
202          raise HypervisorError("Can't stop the processes using the chroot") 
203        return 
204   
205 -  def CleanupInstance(self, instance_name): 
206      """Cleanup after a stopped instance 
207   
208      """ 
209      root_dir = self._InstanceDir(instance_name) 
210   
211      if not os.path.exists(root_dir): 
212        return 
213   
214      if self._IsDirLive(root_dir): 
215        raise HypervisorError("Processes are still using the chroot") 
216   
217      for mpath in self._GetMountSubdirs(root_dir): 
218        utils.RunCmd(["umount", mpath]) 
219   
220      result = utils.RunCmd(["umount", root_dir]) 
221      if result.failed: 
222        msg = ("Processes still alive in the chroot: %s" % 
223               utils.RunCmd("fuser -vm %s" % root_dir).output) 
224        logging.error(msg) 
225        raise HypervisorError("Can't umount the chroot dir: %s (%s)" % 
226                              (result.output, msg)) 
227   
228 -  def RebootInstance(self, instance): 
229      """Reboot an instance. 
230   
231      This is not (yet) implemented for the chroot manager. 
232   
233      """ 
234      raise HypervisorError("The chroot manager doesn't implement the" 
235                            " reboot functionality") 
236   
237 -  def BalloonInstanceMemory(self, instance, mem): 
238      """Balloon an instance memory to a certain value. 
239   
240      @type instance: L{objects.Instance} 
241      @param instance: instance to be accepted 
242      @type mem: int 
243      @param mem: actual memory size to use for instance runtime 
244   
245      """ 
246      # Currently chroots don't have memory limits 
247      pass 
248   
249 -  def GetNodeInfo(self): 
250      """Return information about the node. 
251   
252      This is just a wrapper over the base GetLinuxNodeInfo method. 
253   
254      @return: a dict with the following keys (values in MiB): 
255            - memory_total: the total memory size on the node 
256            - memory_free: the available memory on the node for instances 
257            - memory_dom0: the memory used by the node itself, if available 
258   
259      """ 
260      return self.GetLinuxNodeInfo() 
261   
262    @classmethod 
263 -  def GetInstanceConsole(cls, instance, # pylint: disable=W0221 
264                           hvparams, beparams, root_dir=None): 
265      """Return information for connecting to the console of an instance. 
266   
267      """ 
268      if root_dir is None: 
269        root_dir = cls._InstanceDir(instance.name) 
270        if not os.path.ismount(root_dir): 
271          raise HypervisorError("Instance %s is not running" % instance.name) 
272   
273      return objects.InstanceConsole(instance=instance.name, 
274                                     kind=constants.CONS_SSH, 
275                                     host=instance.primary_node, 
276                                     user=constants.SSH_CONSOLE_USER, 
277                                     command=["chroot", root_dir]) 
278   
279 -  def Verify(self): 
280      """Verify the hypervisor. 
281   
282      For the chroot manager, it just checks the existence of the base dir. 
283   
284      @return: Problem description if something is wrong, C{None} otherwise 
285   
286      """ 
287      if os.path.exists(self._ROOT_DIR): 
288        return None 
289      else: 
290        return "The required directory '%s' does not exist" % self._ROOT_DIR 
291   
292    @classmethod 
293 -  def PowercycleNode(cls): 
294      """Chroot powercycle, just a wrapper over Linux powercycle. 
295   
296      """ 
297      cls.LinuxPowercycle() 
298   
299 -  def MigrateInstance(self, instance, target, live): 
300      """Migrate an instance. 
301   
302      @type instance: L{objects.Instance} 
303      @param instance: the instance to be migrated 
304      @type target: string 
305      @param target: hostname (usually ip) of the target node 
306      @type live: boolean 
307      @param live: whether to do a live or non-live migration 
308   
309      """ 
310      raise HypervisorError("Migration not supported by the chroot hypervisor") 
311   
312 -  def GetMigrationStatus(self, instance): 
313      """Get the migration status 
314   
315      @type instance: L{objects.Instance} 
316      @param instance: the instance that is being migrated 
317      @rtype: L{objects.MigrationStatus} 
318      @return: the status of the current migration (one of 
319               L{constants.HV_MIGRATION_VALID_STATUSES}), plus any additional 
320               progress info that can be retrieved from the hypervisor 
321   
322      """ 
323      raise HypervisorError("Migration not supported by the chroot hypervisor") 
324