root / lib / ssconf.py @ a8083063
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#!/usr/bin/python
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#
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# Copyright (C) 2006, 2007 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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"""Global Configuration data for Ganeti.
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This module provides the interface to a special case of cluster
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configuration data, which is mostly static and available to all nodes.
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"""
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import os |
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import tempfile |
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import errno |
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import socket |
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from ganeti import errors |
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from ganeti import constants |
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class SimpleStore: |
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"""Interface to static cluster data.
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This is different that the config.ConfigWriter class in that it
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holds data that is (mostly) constant after the cluster
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initialization. Its purpose is to allow limited customization of
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things which would otherwise normally live in constants.py. Note
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that this data cannot live in ConfigWriter as that is available only
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on the master node, and our data must be readable by both the master
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and the nodes.
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Other particularities of the datastore:
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- keys are restricted to predefined values
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- values are small (<4k)
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- since the data is practically static, read keys are cached in memory
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- some keys are handled specially (read from the system, so
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we can't update them)
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"""
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_SS_FILEPREFIX = "ssconf_"
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SS_HYPERVISOR = "hypervisor"
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SS_NODED_PASS = "node_pass"
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_VALID_KEYS = (SS_HYPERVISOR, SS_NODED_PASS,) |
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_MAX_SIZE = 4096
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def __init__(self, cfg_location=None): |
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if cfg_location is None: |
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self._cfg_dir = constants.DATA_DIR
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else:
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self._cfg_dir = cfg_location
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self._cache = {}
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def KeyToFilename(self, key): |
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"""Convert a given key into filename.
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"""
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if key not in self._VALID_KEYS: |
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raise errors.ProgrammerError, ("Invalid key requested from SSConf: '%s'" |
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% str(key))
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filename = self._cfg_dir + '/' + self._SS_FILEPREFIX + key |
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return filename
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def _ReadFile(self, key): |
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"""Generic routine to read keys.
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This will read the file which holds the value requested. Errors
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will be changed into ConfigurationErrors.
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"""
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if key in self._cache: |
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return self._cache[key] |
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filename = self.KeyToFilename(key)
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try:
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fh = file(filename, 'r') |
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try:
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data = fh.readline(self._MAX_SIZE)
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data = data.rstrip('\n')
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finally:
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fh.close() |
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except EnvironmentError, err: |
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raise errors.ConfigurationError, ("Can't read from the ssconf file:" |
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" '%s'" % str(err)) |
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self._cache[key] = data
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return data
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def GetNodeDaemonPort(self): |
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"""Get the node daemon port for this cluster.
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Note that this routine does not read a ganeti-specific file, but
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instead uses socket.getservbyname to allow pre-customization of
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this parameter outside of ganeti.
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"""
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try:
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port = socket.getservbyname("ganeti-noded", "tcp") |
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except socket.error:
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port = constants.DEFAULT_NODED_PORT |
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return port
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def GetHypervisorType(self): |
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"""Get the hypervisor type for this cluster.
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"""
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return self._ReadFile(self.SS_HYPERVISOR) |
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def GetNodeDaemonPassword(self): |
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"""Get the node password for this cluster.
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"""
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return self._ReadFile(self.SS_NODED_PASS) |
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def SetKey(self, key, value): |
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"""Set the value of a key.
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This should be used only when adding a node to a cluster.
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"""
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file_name = self.KeyToFilename(key)
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dir_name, small_name = os.path.split(file_name) |
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fd, new_name = tempfile.mkstemp('.new', small_name, dir_name)
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# here we need to make sure we remove the temp file, if any error
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# leaves it in place
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try:
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os.chown(new_name, 0, 0) |
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os.chmod(new_name, 0400)
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os.write(fd, "%s\n" % str(value)) |
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os.fsync(fd) |
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os.rename(new_name, file_name) |
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self._cache[key] = value
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finally:
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os.close(fd) |
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try:
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os.unlink(new_name) |
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except OSError, err: |
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if err.errno != errno.ENOENT:
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raise
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def GetFileList(self): |
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"""Return the lis of all config files.
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This is used for computing node replication data.
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"""
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return [self.KeyToFilename(key) for key in self._VALID_KEYS] |