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