ganeti.hypervisor.hv

40 """LXC-based virtualization. 41 42 Since current (Spring 2010) distributions are not yet ready for 43 running under a container, the following changes must be done 44 manually: 45 - remove udev 46 - disable the kernel log component of sysklogd/rsyslog/etc., 47 otherwise they will fail to read the log, and at least rsyslog 48 will fill the filesystem with error messages 49 50 TODO: 51 - move hardcoded parameters into hypervisor parameters, once we 52 have the container-parameter support 53 - implement memory limits, but only optionally, depending on host 54 kernel support 55 56 Problems/issues: 57 - LXC is very temperamental; in daemon mode, it succeeds or fails 58 in launching the instance silently, without any error 59 indication, and when failing it can leave network interfaces 60 around, and future successful startups will list the instance 61 twice 62 - shutdown sequence of containers leaves the init 'dead', and the 63 container effectively stopped, but LXC still believes the 64 container to be running; need to investigate using the 65 notify_on_release and release_agent feature of cgroups 66 67 """ 68 _ROOT_DIR = constants.RUN_GANETI_DIR + "/lxc" 69 _DEVS = [ 70 "c 1:3", # /dev/null 71 "c 1:5", # /dev/zero 72 "c 1:7", # /dev/full 73 "c 1:8", # /dev/random 74 "c 1:9", # /dev/urandom 75 "c 1:10", # /dev/aio 76 "c 5:0", # /dev/tty 77 "c 5:1", # /dev/console 78 "c 5:2", # /dev/ptmx 79 "c 136:*", # first block of Unix98 PTY slaves 80 ] 81 _DENIED_CAPABILITIES = [ 82 "mac_override", # Allow MAC configuration or state changes 83 # TODO: remove sys_admin too, for safety 84 #"sys_admin", # Perform a range of system administration operations 85 "sys_boot", # Use reboot(2) and kexec_load(2) 86 "sys_module", # Load and unload kernel modules 87 "sys_time", # Set system clock, set real-time (hardware) clock 88 ] 89 _DIR_MODE = 0755 90 91 PARAMETERS = { 92 constants.HV_CPU_MASK: hv_base.OPT_CPU_MASK_CHECK, 93 } 94

95 - def __init__(self):

96 hv_base.BaseHypervisor.__init__(self) 97 utils.EnsureDirs([(self._ROOT_DIR, self._DIR_MODE)])

98 99 @staticmethod

100 - def _GetMountSubdirs(path):

101 """Return the list of mountpoints under a given path. 102 103 """ 104 result = [] 105 for _, mountpoint, _, _ in utils.GetMounts(): 106 if (mountpoint.startswith(path) and 107 mountpoint != path): 108 result.append(mountpoint) 109 110 result.sort(key=lambda x: x.count("/"), reverse=True) 111 return result

112 113 @classmethod

114 - def _InstanceDir(cls, instance_name):

115 """Return the root directory for an instance. 116 117 """ 118 return utils.PathJoin(cls._ROOT_DIR, instance_name)

119 120 @classmethod

121 - def _InstanceConfFile(cls, instance_name):

122 """Return the configuration file for an instance. 123 124 """ 125 return utils.PathJoin(cls._ROOT_DIR, instance_name + ".conf")

126 127 @classmethod

128 - def _InstanceLogFile(cls, instance_name):

129 """Return the log file for an instance. 130 131 """ 132 return utils.PathJoin(cls._ROOT_DIR, instance_name + ".log")

133 134 @classmethod

135 - def _GetCgroupMountPoint(cls):

136 for _, mountpoint, fstype, _ in utils.GetMounts(): 137 if fstype == "cgroup": 138 return mountpoint 139 raise errors.HypervisorError("The cgroup filesystem is not mounted")

140 141 @classmethod

142 - def _GetCgroupCpuList(cls, instance_name):

143 """Return the list of CPU ids for an instance. 144 145 """ 146 cgroup = cls._GetCgroupMountPoint() 147 try: 148 cpus = utils.ReadFile(utils.PathJoin(cgroup, 149 instance_name, 150 "cpuset.cpus")) 151 except EnvironmentError, err: 152 raise errors.HypervisorError("Getting CPU list for instance" 153 " %s failed: %s" % (instance_name, err)) 154 155 return utils.ParseCpuMask(cpus)

156

157 - def ListInstances(self):

158 """Get the list of running instances. 159 160 """ 161 result = utils.RunCmd(["lxc-ls"]) 162 if result.failed: 163 raise errors.HypervisorError("Running lxc-ls failed: %s" % result.output) 164 return result.stdout.splitlines()

165

166 - def GetInstanceInfo(self, instance_name):

167 """Get instance properties. 168 169 @type instance_name: string 170 @param instance_name: the instance name 171 172 @return: (name, id, memory, vcpus, stat, times) 173 174 """ 175 # TODO: read container info from the cgroup mountpoint 176 177 result = utils.RunCmd(["lxc-info", "-n", instance_name]) 178 if result.failed: 179 raise errors.HypervisorError("Running lxc-info failed: %s" % 180 result.output) 181 # lxc-info output examples: 182 # 'ganeti-lxc-test1' is STOPPED 183 # 'ganeti-lxc-test1' is RUNNING 184 _, state = result.stdout.rsplit(None, 1) 185 if state != "RUNNING": 186 return None 187 188 cpu_list = self._GetCgroupCpuList(instance_name) 189 return (instance_name, 0, 0, len(cpu_list), 0, 0)

190

191 - def GetAllInstancesInfo(self):

192 """Get properties of all instances. 193 194 @return: [(name, id, memory, vcpus, stat, times),...] 195 196 """ 197 data = [] 198 for name in self.ListInstances(): 199 data.append(self.GetInstanceInfo(name)) 200 return data

201

202 - def _CreateConfigFile(self, instance, root_dir):

203 """Create an lxc.conf file for an instance. 204 205 """ 206 out = [] 207 # hostname 208 out.append("lxc.utsname = %s" % instance.name) 209 210 # separate pseudo-TTY instances 211 out.append("lxc.pts = 255") 212 # standard TTYs 213 out.append("lxc.tty = 6") 214 # console log file 215 console_log = utils.PathJoin(self._ROOT_DIR, instance.name + ".console") 216 try: 217 utils.WriteFile(console_log, data="", mode=constants.SECURE_FILE_MODE) 218 except EnvironmentError, err: 219 raise errors.HypervisorError("Creating console log file %s for" 220 " instance %s failed: %s" % 221 (console_log, instance.name, err)) 222 out.append("lxc.console = %s" % console_log) 223 224 # root FS 225 out.append("lxc.rootfs = %s" % root_dir) 226 227 # TODO: additional mounts, if we disable CAP_SYS_ADMIN 228 229 # CPUs 230 if instance.hvparams[constants.HV_CPU_MASK]: 231 cpu_list = utils.ParseCpuMask(instance.hvparams[constants.HV_CPU_MASK]) 232 cpus_in_mask = len(cpu_list) 233 if cpus_in_mask != instance.beparams["vcpus"]: 234 raise errors.HypervisorError("Number of VCPUs (%d) doesn't match" 235 " the number of CPUs in the" 236 " cpu_mask (%d)" % 237 (instance.beparams["vcpus"], 238 cpus_in_mask)) 239 out.append("lxc.cgroup.cpuset.cpus = %s" % 240 instance.hvparams[constants.HV_CPU_MASK]) 241 242 # Device control 243 # deny direct device access 244 out.append("lxc.cgroup.devices.deny = a") 245 for devinfo in self._DEVS: 246 out.append("lxc.cgroup.devices.allow = %s rw" % devinfo) 247 248 # Networking 249 for idx, nic in enumerate(instance.nics): 250 out.append("# NIC %d" % idx) 251 mode = nic.nicparams[constants.NIC_MODE] 252 link = nic.nicparams[constants.NIC_LINK] 253 if mode == constants.NIC_MODE_BRIDGED: 254 out.append("lxc.network.type = veth") 255 out.append("lxc.network.link = %s" % link) 256 else: 257 raise errors.HypervisorError("LXC hypervisor only supports" 258 " bridged mode (NIC %d has mode %s)" % 259 (idx, mode)) 260 out.append("lxc.network.hwaddr = %s" % nic.mac) 261 out.append("lxc.network.flags = up") 262 263 # Capabilities 264 for cap in self._DENIED_CAPABILITIES: 265 out.append("lxc.cap.drop = %s" % cap) 266 267 return "\n".join(out) + "\n"

268

269 - def StartInstance(self, instance, block_devices):

270 """Start an instance. 271 272 For LCX, we try to mount the block device and execute 'lxc-start'. 273 We use volatile containers. 274 275 """ 276 root_dir = self._InstanceDir(instance.name) 277 try: 278 utils.EnsureDirs([(root_dir, self._DIR_MODE)]) 279 except errors.GenericError, err: 280 raise HypervisorError("Creating instance directory failed: %s", str(err)) 281 282 conf_file = self._InstanceConfFile(instance.name) 283 utils.WriteFile(conf_file, data=self._CreateConfigFile(instance, root_dir)) 284 285 log_file = self._InstanceLogFile(instance.name) 286 if not os.path.exists(log_file): 287 try: 288 utils.WriteFile(log_file, data="", mode=constants.SECURE_FILE_MODE) 289 except EnvironmentError, err: 290 raise errors.HypervisorError("Creating hypervisor log file %s for" 291 " instance %s failed: %s" % 292 (log_file, instance.name, err)) 293 294 if not os.path.ismount(root_dir): 295 if not block_devices: 296 raise HypervisorError("LXC needs at least one disk") 297 298 sda_dev_path = block_devices[0][1] 299 result = utils.RunCmd(["mount", sda_dev_path, root_dir]) 300 if result.failed: 301 raise HypervisorError("Mounting the root dir of LXC instance %s" 302 " failed: %s" % (instance.name, result.output)) 303 result = utils.RunCmd(["lxc-start", "-n", instance.name, 304 "-o", log_file, 305 "-l", "DEBUG", 306 "-f", conf_file, "-d"]) 307 if result.failed: 308 raise HypervisorError("Running the lxc-start script failed: %s" % 309 result.output)

310

311 - def StopInstance(self, instance, force=False, retry=False, name=None):

312 """Stop an instance. 313 314 This method has complicated cleanup tests, as we must: 315 - try to kill all leftover processes 316 - try to unmount any additional sub-mountpoints 317 - finally unmount the instance dir 318 319 """ 320 if name is None: 321 name = instance.name 322 323 root_dir = self._InstanceDir(name) 324 if not os.path.exists(root_dir): 325 return 326 327 if name in self.ListInstances(): 328 # Signal init to shutdown; this is a hack 329 if not retry and not force: 330 result = utils.RunCmd(["chroot", root_dir, "poweroff"]) 331 if result.failed: 332 raise HypervisorError("Running 'poweroff' on the instance" 333 " failed: %s" % result.output) 334 time.sleep(2) 335 result = utils.RunCmd(["lxc-stop", "-n", name]) 336 if result.failed: 337 logging.warning("Error while doing lxc-stop for %s: %s", name, 338 result.output) 339 340 for mpath in self._GetMountSubdirs(root_dir): 341 result = utils.RunCmd(["umount", mpath]) 342 if result.failed: 343 logging.warning("Error while umounting subpath %s for instance %s: %s", 344 mpath, name, result.output) 345 346 result = utils.RunCmd(["umount", root_dir]) 347 if result.failed and force: 348 msg = ("Processes still alive in the chroot: %s" % 349 utils.RunCmd("fuser -vm %s" % root_dir).output) 350 logging.error(msg) 351 raise HypervisorError("Unmounting the chroot dir failed: %s (%s)" % 352 (result.output, msg))

353

354 - def RebootInstance(self, instance):

355 """Reboot an instance. 356 357 This is not (yet) implemented (in Ganeti) for the LXC hypervisor. 358 359 """ 360 # TODO: implement reboot 361 raise HypervisorError("The LXC hypervisor doesn't implement the" 362 " reboot functionality")

363

364 - def GetNodeInfo(self):

365 """Return information about the node. 366 367 This is just a wrapper over the base GetLinuxNodeInfo method. 368 369 @return: a dict with the following keys (values in MiB): 370 - memory_total: the total memory size on the node 371 - memory_free: the available memory on the node for instances 372 - memory_dom0: the memory used by the node itself, if available 373 374 """ 375 return self.GetLinuxNodeInfo()

376 377 @classmethod

378 - def GetInstanceConsole(cls, instance, hvparams, beparams):

379 """Return a command for connecting to the console of an instance. 380 381 """ 382 return objects.InstanceConsole(instance=instance.name, 383 kind=constants.CONS_SSH, 384 host=instance.primary_node, 385 user=constants.GANETI_RUNAS, 386 command=["lxc-console", "-n", instance.name])

387

388 - def Verify(self):

389 """Verify the hypervisor. 390 391 For the chroot manager, it just checks the existence of the base dir. 392 393 """ 394 if not os.path.exists(self._ROOT_DIR): 395 return "The required directory '%s' does not exist." % self._ROOT_DIR

396 397 @classmethod

398 - def PowercycleNode(cls):

399 """LXC powercycle, just a wrapper over Linux powercycle. 400 401 """ 402 cls.LinuxPowercycle()

403

404 - def MigrateInstance(self, instance, target, live):

405 """Migrate an instance. 406 407 @type instance: L{objects.Instance} 408 @param instance: the instance to be migrated 409 @type target: string 410 @param target: hostname (usually ip) of the target node 411 @type live: boolean 412 @param live: whether to do a live or non-live migration 413 414 """ 415 raise HypervisorError("Migration is not supported by the LXC hypervisor")

Source Code for Module ganeti.hypervisor.hv_lxc