root / lib / hypervisor / hv_chroot.py @ 3a488770
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# Copyright (C) 2006, 2007, 2008, 2009 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Chroot manager hypervisor
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"""
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import os |
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import os.path |
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import time |
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import logging |
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from ganeti import constants |
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from ganeti import errors # pylint: disable-msg=W0611 |
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from ganeti import utils |
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from ganeti.hypervisor import hv_base |
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from ganeti.errors import HypervisorError |
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class ChrootManager(hv_base.BaseHypervisor): |
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"""Chroot manager.
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This not-really hypervisor allows ganeti to manage chroots. It has
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special behaviour and requirements on the OS definition and the node
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environemnt:
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- the start and stop of the chroot environment are done via a
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script called ganeti-chroot located in the root directory of the
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first drive, which should be created by the OS definition
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- this script must accept the start and stop argument and, on
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shutdown, it should cleanly shutdown the daemons/processes
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using the chroot
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- the daemons run in chroot should only bind to the instance IP
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(to which the OS create script has access via the instance name)
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- since some daemons in the node could be listening on the wildcard
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address, some ports might be unavailable
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- the instance listing will show no memory usage
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- on shutdown, the chroot manager will try to find all mountpoints
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under the root dir of the instance and unmount them
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- instance alive check is based on whether any process is using the chroot
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"""
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_ROOT_DIR = constants.RUN_GANETI_DIR + "/chroot-hypervisor"
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PARAMETERS = { |
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constants.HV_INIT_SCRIPT: (True, utils.IsNormAbsPath,
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"must be an absolute normalized path",
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None, None), |
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} |
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def __init__(self): |
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hv_base.BaseHypervisor.__init__(self)
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if not os.path.exists(self._ROOT_DIR): |
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os.mkdir(self._ROOT_DIR)
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if not os.path.isdir(self._ROOT_DIR): |
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raise HypervisorError("Needed path %s is not a directory" % |
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self._ROOT_DIR)
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@staticmethod
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def _IsDirLive(path): |
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"""Check if a directory looks like a live chroot.
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"""
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if not os.path.ismount(path): |
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return False |
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result = utils.RunCmd(["fuser", "-m", path]) |
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return not result.failed |
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@staticmethod
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def _GetMountSubdirs(path): |
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"""Return the list of mountpoints under a given path.
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This function is Linux-specific.
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"""
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#TODO(iustin): investigate and document non-linux options
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#(e.g. via mount output)
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data = [] |
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fh = open("/proc/mounts", "r") |
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try:
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for line in fh: |
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_, mountpoint, _ = line.split(" ", 2) |
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if (mountpoint.startswith(path) and |
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mountpoint != path): |
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data.append(mountpoint) |
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finally:
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fh.close() |
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data.sort(key=lambda x: x.count("/"), reverse=True) |
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return data
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@classmethod
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def _InstanceDir(cls, instance_name): |
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"""Return the root directory for an instance.
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"""
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return utils.PathJoin(cls._ROOT_DIR, instance_name)
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def ListInstances(self): |
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"""Get the list of running instances.
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"""
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return [name for name in os.listdir(self._ROOT_DIR) |
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if self._IsDirLive(utils.PathJoin(self._ROOT_DIR, name))] |
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def GetInstanceInfo(self, instance_name): |
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"""Get instance properties.
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@type instance_name: string
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@param instance_name: the instance name
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@return: (name, id, memory, vcpus, stat, times)
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"""
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dir_name = self._InstanceDir(instance_name)
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if not self._IsDirLive(dir_name): |
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raise HypervisorError("Instance %s is not running" % instance_name) |
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return (instance_name, 0, 0, 0, 0, 0) |
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def GetAllInstancesInfo(self): |
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"""Get properties of all instances.
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@return: [(name, id, memory, vcpus, stat, times),...]
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"""
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data = [] |
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for file_name in os.listdir(self._ROOT_DIR): |
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path = utils.PathJoin(self._ROOT_DIR, file_name)
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if self._IsDirLive(path): |
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data.append((file_name, 0, 0, 0, 0, 0)) |
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return data
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def StartInstance(self, instance, block_devices): |
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"""Start an instance.
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For the chroot manager, we try to mount the block device and
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execute '/ganeti-chroot start'.
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"""
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root_dir = self._InstanceDir(instance.name)
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if not os.path.exists(root_dir): |
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try:
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os.mkdir(root_dir) |
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except IOError, err: |
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raise HypervisorError("Failed to start instance %s: %s" % |
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(instance.name, err)) |
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if not os.path.isdir(root_dir): |
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raise HypervisorError("Needed path %s is not a directory" % root_dir) |
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if not os.path.ismount(root_dir): |
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if not block_devices: |
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raise HypervisorError("The chroot manager needs at least one disk") |
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sda_dev_path = block_devices[0][1] |
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result = utils.RunCmd(["mount", sda_dev_path, root_dir])
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if result.failed:
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raise HypervisorError("Can't mount the chroot dir: %s" % result.output) |
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init_script = instance.hvparams[constants.HV_INIT_SCRIPT] |
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result = utils.RunCmd(["chroot", root_dir, init_script, "start"]) |
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if result.failed:
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raise HypervisorError("Can't run the chroot start script: %s" % |
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result.output) |
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def StopInstance(self, instance, force=False, retry=False): |
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"""Stop an instance.
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This method has complicated cleanup tests, as we must:
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- try to kill all leftover processes
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- try to unmount any additional sub-mountpoints
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- finally unmount the instance dir
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"""
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root_dir = self._InstanceDir(instance.name)
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if not os.path.exists(root_dir) or not self._IsDirLive(root_dir): |
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return
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# Run the chroot stop script only once
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if not retry and not force: |
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result = utils.RunCmd(["chroot", root_dir, "/ganeti-chroot", "stop"]) |
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if result.failed:
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raise HypervisorError("Can't run the chroot stop script: %s" % |
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result.output) |
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if not force: |
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utils.RunCmd(["fuser", "-k", "-TERM", "-m", root_dir]) |
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else:
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utils.RunCmd(["fuser", "-k", "-KILL", "-m", root_dir]) |
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# 2 seconds at most should be enough for KILL to take action
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time.sleep(2)
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if self._IsDirLive(root_dir): |
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if force:
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raise HypervisorError("Can't stop the processes using the chroot") |
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return
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for mpath in self._GetMountSubdirs(root_dir): |
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utils.RunCmd(["umount", mpath])
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result = utils.RunCmd(["umount", root_dir])
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if result.failed and force: |
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msg = ("Processes still alive in the chroot: %s" %
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utils.RunCmd("fuser -vm %s" % root_dir).output)
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logging.error(msg) |
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raise HypervisorError("Can't umount the chroot dir: %s (%s)" % |
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(result.output, msg)) |
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def RebootInstance(self, instance): |
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"""Reboot an instance.
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This is not (yet) implemented for the chroot manager.
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"""
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raise HypervisorError("The chroot manager doesn't implement the" |
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" reboot functionality")
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def GetNodeInfo(self): |
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"""Return information about the node.
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This is just a wrapper over the base GetLinuxNodeInfo method.
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@return: a dict with the following keys (values in MiB):
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- memory_total: the total memory size on the node
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- memory_free: the available memory on the node for instances
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- memory_dom0: the memory used by the node itself, if available
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"""
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return self.GetLinuxNodeInfo() |
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@classmethod
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def GetShellCommandForConsole(cls, instance, hvparams, beparams): |
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"""Return a command for connecting to the console of an instance.
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"""
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root_dir = cls._InstanceDir(instance.name) |
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if not os.path.ismount(root_dir): |
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raise HypervisorError("Instance %s is not running" % instance.name) |
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return "chroot %s" % root_dir |
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def Verify(self): |
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"""Verify the hypervisor.
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For the chroot manager, it just checks the existence of the base dir.
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"""
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if not os.path.exists(self._ROOT_DIR): |
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return "The required directory '%s' does not exist." % self._ROOT_DIR |
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@classmethod
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def PowercycleNode(cls): |
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"""Chroot powercycle, just a wrapper over Linux powercycle.
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"""
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cls.LinuxPowercycle() |
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def MigrateInstance(self, instance, target, live): |
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"""Migrate an instance.
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@type instance: L{objects.Instance}
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@param instance: the instance to be migrated
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@type target: string
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@param target: hostname (usually ip) of the target node
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@type live: boolean
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@param live: whether to do a live or non-live migration
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"""
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raise HypervisorError("Migration not supported by the chroot hypervisor") |