Package ganeti :: Package hypervisor :: Module hv_chroot
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Source Code for Module ganeti.hypervisor.hv_chroot

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