Heat templates for deploying OpenStack
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#!/usr/bin/env python
#
# Copyright 2018 Red Hat Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
import os
import pwd
import selinux
import stat
import sys
debug = os.getenv('__OS_DEBUG', 'false')
if debug.lower() == 'true':
loglevel = logging.DEBUG
else:
loglevel = logging.INFO
logging.basicConfig(stream=sys.stdout, level=loglevel)
LOG = logging.getLogger('nova_statedir')
class PathManager(object):
"""Helper class to manipulate ownership of a given path"""
def __init__(self, path):
self.path = path
self.uid = None
self.gid = None
self.is_dir = None
self.secontext = None
self._update()
def _update(self):
try:
statinfo = os.stat(self.path)
self.is_dir = stat.S_ISDIR(statinfo.st_mode)
self.uid = statinfo.st_uid
self.gid = statinfo.st_gid
self.secontext = selinux.lgetfilecon(self.path)[1]
except Exception:
LOG.exception('Could not update metadata for %s', self.path)
raise
def __str__(self):
return "uid: {} gid: {} path: {}{}".format(
self.uid,
self.gid,
self.path,
'/' if self.is_dir else ''
)
def has_owner(self, uid, gid):
return self.uid == uid and self.gid == gid
def has_either(self, uid, gid):
return self.uid == uid or self.gid == gid
def chown(self, uid, gid):
target_uid = -1
target_gid = -1
if self.uid != uid:
target_uid = uid
if self.gid != gid:
target_gid = gid
if (target_uid, target_gid) != (-1, -1):
LOG.info('Changing ownership of %s from %d:%d to %d:%d',
self.path,
self.uid,
self.gid,
self.uid if target_uid == -1 else target_uid,
self.gid if target_gid == -1 else target_gid)
try:
os.chown(self.path, target_uid, target_gid)
self._update()
except Exception:
LOG.exception('Could not change ownership of %s: ',
self.path)
raise
else:
LOG.info('Ownership of %s already %d:%d',
self.path,
uid,
gid)
def chcon(self, context):
# If dir returns whether to recusively set context
try:
try:
selinux.lsetfilecon(self.path, context)
LOG.info('Setting selinux context of %s to %s',
self.path, context)
return True
except OSError as e:
if self.is_dir and e.errno == 95:
# Operation not supported, assume NFS mount and skip
LOG.info('Setting selinux context not supported for %s',
self.path)
return False
else:
raise
except Exception:
LOG.exception('Could not set selinux context of %s to %s:',
self.path, context)
raise
class NovaStatedirOwnershipManager(object):
"""Class to manipulate the ownership of the nova statedir (/var/lib/nova).
The nova uid/gid differ on the host and container images. An upgrade
that switches from host systemd services to docker requires a change in
ownership. Previously this was a naive recursive chown, however this
causes issues if nova instance are shared via an NFS mount: any open
filehandles in qemu/libvirt fail with an I/O error (LP1778465).
Instead the upgrade/FFU ansible tasks now lay down a marker file when
stopping and disabling the host systemd services. We use this file to
determine the host nova uid/gid. We then walk the tree and update any
files that have the host uid/gid to the docker nova uid/gid. As files
owned by root/qemu etc... are ignored this avoids the issues with open
filehandles. The marker is removed once the tree has been walked.
For subsequent runs, or for a new deployment, we simply ensure that the
docker nova user/group owns all directories. This is required as the
directories are created with root ownership in host_prep_tasks (the
docker nova uid/gid is not known in this context).
"""
def __init__(self, statedir, upgrade_marker='upgrade_marker',
nova_user='nova', secontext_marker='../_nova_secontext',
exclude_paths=None):
self.statedir = statedir
self.nova_user = nova_user
self.upgrade_marker_path = os.path.join(statedir, upgrade_marker)
self.secontext_marker_path = os.path.normpath(os.path.join(statedir, secontext_marker))
self.upgrade = os.path.exists(self.upgrade_marker_path)
self.exclude_paths = [self.upgrade_marker_path]
if exclude_paths is not None:
for p in exclude_paths:
if not p.startswith(os.path.sep):
p = os.path.join(self.statedir, p)
self.exclude_paths.append(p)
self.target_uid, self.target_gid = self._get_nova_ids()
self.previous_uid, self.previous_gid = self._get_previous_nova_ids()
self.id_change = (self.target_uid, self.target_gid) != \
(self.previous_uid, self.previous_gid)
self.target_secontext = self._get_secontext()
def _get_nova_ids(self):
nova_uid, nova_gid = pwd.getpwnam(self.nova_user)[2:4]
return nova_uid, nova_gid
def _get_previous_nova_ids(self):
if self.upgrade:
statinfo = os.stat(self.upgrade_marker_path)
return statinfo.st_uid, statinfo.st_gid
else:
return self._get_nova_ids()
def _get_secontext(self):
if os.path.exists(self.secontext_marker_path):
return selinux.lgetfilecon(self.secontext_marker_path)[1]
else:
return None
def _walk(self, top, chcon=True):
for f in os.listdir(top):
pathname = os.path.join(top, f)
if pathname in self.exclude_paths:
continue
try:
pathinfo = PathManager(pathname)
LOG.info("Checking %s", pathinfo)
if pathinfo.is_dir:
# Always chown the directories
pathinfo.chown(self.target_uid, self.target_gid)
chcon_r = chcon
if chcon:
chcon_r = pathinfo.chcon(self.target_secontext)
self._walk(pathname, chcon_r)
elif self.id_change:
# Only chown files if it's an upgrade and the file is owned by
# the host nova uid/gid
pathinfo.chown(
self.target_uid if pathinfo.uid == self.previous_uid
else pathinfo.uid,
self.target_gid if pathinfo.gid == self.previous_gid
else pathinfo.gid
)
if chcon:
pathinfo.chcon(self.target_secontext)
except Exception:
# Likely to have been caused by external systems
# interacting with this directory tree,
# especially on NFS e.g snapshot dirs.
# Just ignore it and continue on to the next entry
continue
def run(self):
LOG.info('Applying nova statedir ownership')
LOG.info('Target ownership for %s: %d:%d',
self.statedir,
self.target_uid,
self.target_gid)
pathinfo = PathManager(self.statedir)
LOG.info("Checking %s", pathinfo)
pathinfo.chown(self.target_uid, self.target_gid)
chcon = self.target_secontext is not None
if chcon:
pathinfo.chcon(self.target_secontext)
self._walk(self.statedir, chcon)
if self.upgrade:
LOG.info('Removing upgrade_marker %s',
self.upgrade_marker_path)
os.unlink(self.upgrade_marker_path)
LOG.info('Nova statedir ownership complete')
def get_exclude_paths():
exclude_paths = os.environ.get('NOVA_STATEDIR_OWNERSHIP_SKIP')
if exclude_paths is not None:
exclude_paths = exclude_paths.split(os.pathsep)
return exclude_paths
if __name__ == '__main__':
NovaStatedirOwnershipManager('/var/lib/nova', exclude_paths=get_exclude_paths())