diskimage-builder/diskimage_builder/block_device/level1/lvm.py

407 lines
13 KiB
Python

# Copyright 2017 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
from diskimage_builder.block_device.exception \
import BlockDeviceSetupException
from diskimage_builder.block_device.plugin import NodeBase
from diskimage_builder.block_device.plugin import PluginBase
from diskimage_builder.block_device.utils import exec_sudo
from diskimage_builder.block_device.utils import parse_abs_size_spec
PHYSICAL_EXTENT_BYTES = parse_abs_size_spec('4MiB')
logger = logging.getLogger(__name__)
#
# LVM
# ---
#
# The LVM config has three required keys; pvs, vgs and lvs
#
# lvm: -> LVSNode
# pvs: -> PvsNode
# lvs: -> LvsNode
# vgs: -> VgsNode
#
# The LVMPlugin will verify this and build nodes into the
# configuration graph.
#
# As described below, a LVSNode is created for synchronisation
# purposes. Thus if you had something like two partitions that became
# two physical-volumes (pv1 & pv2), that you then combine into a
# single volume group (vg) and then create several logical volumes
# (lv1, lv2, lv3) your graph would end up looking like:
#
# partition1 partition2
# | |
# ---> LVSNode <--+
# |
# +------+------+
# v v
# pv1 pv2
# | |
# +--> vg <---+
# |
# +-----+-----+
# v v v
# lv1 lv2 lv3
#
# After the create() call on the LVSNode object, the entire LVM setup
# would actually be complete. The other nodes are all just
# place-holders, and are used for further ordering (for example, the
# fs creation & mounting should depend on the logical volume nodes).
# For this reason, their create() calls are blank. However, for code
# organisational purposes they have a private _create() and _cleanup()
# call that is driven by the LVSNode object.
class PvsNode(NodeBase):
def __init__(self, name, state, base, options):
"""Physical volume
This is a placeholder node for the LVM physical volumes.
Arguments:
:param name: Name of this node
:param state: global state pointer
:param base: Parent partition
:param options: config options
"""
super(PvsNode, self).__init__(name, state)
self.base = base
self.options = options
def _create(self):
# the underlying device path of our parent was previously
# recorded into the state during blockdev creation; look it
# up.
phys_dev = self.state['blockdev'][self.base]['device']
cmd = ["pvcreate"]
cmd.append(phys_dev)
if self.options:
cmd.extend(self.options)
logger.debug("Creating pv command [%s]", cmd)
exec_sudo(cmd)
# save state
if 'pvs' not in self.state:
self.state['pvs'] = {}
self.state['pvs'][self.name] = {
'opts': self.options,
'device': phys_dev
}
def get_edges(self):
# See LVMNode.get_edges() for how this gets connected
return ([], [])
def create(self):
# see notes in LVMNode object
pass
class VgsNode(NodeBase):
def __init__(self, name, state, base, options):
"""Volume Group
This is a placeholder node for a volume group
Arguments:
:param name: Name of this node
:param state: global state pointer
:param base: Parent :class:`PvsNodes` this volume group exists on
:param options: extra options passed to the `vgcreate` command
"""
super(VgsNode, self).__init__(name, state)
self.base = base
self.options = options
def _create(self):
# The PV's have saved their actual device name into the state
# during their _create(). Look at our base elements and thus
# find the underlying device paths in the state.
pvs_devs = []
for pv in self.base:
pvs_dev = self.state['pvs'][pv]['device']
pvs_devs.append(pvs_dev)
cmd = ["vgcreate", ]
cmd.append(self.name)
cmd.extend(pvs_devs)
if self.options:
cmd.extend(self.options)
logger.debug("Creating vg command [%s]", cmd)
exec_sudo(cmd)
# save state
if 'vgs' not in self.state:
self.state['vgs'] = {}
self.state['vgs'][self.name] = {
'opts': self.options,
'devices': self.base,
}
def _umount(self):
exec_sudo(['vgchange', '-an', self.name])
def get_edges(self):
# self.base is already a list, per the config. There might be
# multiple pv parents here.
edge_from = self.base
edge_to = []
return (edge_from, edge_to)
def create(self):
# see notes in LVMNode object
pass
class LvsNode(NodeBase):
def __init__(self, name, state, base, options, size, extents):
"""Logical Volume
This is a placeholder node for a logical volume
Arguments:
:param name: Name of this node
:param state: global state pointer
:param base: the parent volume group
:param options: options passed to lvcreate
:param size: size of the LV, using the supported unit types
(MB, MiB, etc)
:param extents: size of the LV in extents
"""
super(LvsNode, self).__init__(name, state)
self.base = base
self.options = options
self.size = size
self.extents = extents
def _create(self):
cmd = ["lvcreate", ]
cmd.extend(['--name', self.name])
if self.size:
size = parse_abs_size_spec(self.size)
# ensuire size aligns with physical extents
size = size - size % PHYSICAL_EXTENT_BYTES
cmd.extend(['-L', '%dB' % size])
elif self.extents:
cmd.extend(['-l', self.extents])
if self.options:
cmd.extend(self.options)
cmd.append(self.base)
logger.debug("Creating lv command [%s]", cmd)
exec_sudo(cmd)
# save state
self.state['blockdev'][self.name] = {
'vgs': self.base,
'size': self.size,
'extents': self.extents,
'opts': self.options,
'device': '/dev/mapper/%s-%s' % (self.base, self.name)
}
def _umount(self):
exec_sudo(['lvchange', '-an',
'/dev/%s/%s' % (self.base, self.name)])
def get_edges(self):
edge_from = [self.base]
edge_to = []
return (edge_from, edge_to)
def create(self):
# see notes in LVMNode object
pass
class LVMNode(NodeBase):
def __init__(self, name, state, pvs, lvs, vgs):
"""LVM Driver Node
This is the "global" node where all LVM operations are driven
from. In the node graph, the LVM physical-volumes depend on
this node. This node then depends on the devices that the
PV's require. This node incorporates *all* LVM setup;
i.e. after the create() call here we have created all pv's,
lv's and vg. The <Pvs|Lvs|Vgs>Node objects in the graph are
therefore just dependency place holders whose create() call
does nothing.
Arguments:
:param name: name of this node
:param state: global state pointer
:param pvs: A list of :class:`PvsNode` objects
:param lvs: A list of :class:`LvsNode` objects
:param vgs: A list of :class:`VgsNode` objects
"""
super(LVMNode, self).__init__(name, state)
self.pvs = pvs
self.lvs = lvs
self.vgs = vgs
def get_edges(self):
# This node requires the physical device(s), which is
# recorded in the "base" argument of the PV nodes.
pvs = []
for pv in self.pvs:
pvs.append(pv.base)
edge_from = set(pvs)
# The PV nodes should then depend on us. i.e., we just made
# this node a synchronisation point
edge_to = [pv.name for pv in self.pvs]
return (edge_from, edge_to)
def create(self):
# Run through pvs->vgs->lvs and create them
# XXX: we could theoretically get this same info from walking
# the graph of our children nodes? Would that be helpful in
# any way?
for pvs in self.pvs:
pvs._create()
for vgs in self.vgs:
vgs._create()
for lvs in self.lvs:
lvs._create()
def umount(self):
for lvs in self.lvs:
lvs._umount()
for vgs in self.vgs:
vgs._umount()
exec_sudo(['udevadm', 'settle'])
def cleanup(self):
# Information about the PV, VG and LV is typically
# cached in lvmetad. Even after removing PV device and
# partitions this data is not automatically updated
# which leads to a couple of problems.
# the 'pvscan --cache' scans the available disks
# and updates the cache.
# This is in cleanup because it must be called after the
# umount of the containing block device is done, (which should
# all be done in umount phase).
try:
exec_sudo(['pvscan', '--cache'])
except BlockDeviceSetupException as e:
logger.info("pvscan call failed [%s]", e.returncode)
class LVMPlugin(PluginBase):
def _config_error(self, msg):
raise BlockDeviceSetupException(msg)
def __init__(self, config, defaults, state):
"""Build LVM nodes
This reads the "lvm:" config stanza, validates it and produces
the PV, VG and LV nodes. These are all synchronised via a
LVMNode as described above.
Arguments:
:param config: "lvm" configuration dictionary
:param defaults: global defaults dictionary
:param state: global state reference
"""
super(LVMPlugin, self).__init__()
# note lvm: doesn't require a base ... the base is the
# physical devices the "pvs" nodes are made on.
if 'name' not in config:
self._config_error("Lvm config requires 'name'")
if 'pvs' not in config:
self._config_error("Lvm config requires a 'pvs'")
if 'vgs' not in config:
self._config_error("Lvm config needs 'vgs'")
if 'lvs' not in config:
self._config_error("Lvm config needs 'lvs'")
# create physical volume nodes
self.pvs = []
self.pvs_keys = []
for pvs_cfg in config['pvs']:
if 'name' not in pvs_cfg:
self._config_error("Missing 'name' in pvs config")
if 'base' not in pvs_cfg:
self._config_error("Missing 'base' in pvs_config")
pvs_item = PvsNode(pvs_cfg['name'], state,
pvs_cfg['base'],
pvs_cfg.get('options'))
self.pvs.append(pvs_item)
# create volume group nodes
self.vgs = []
self.vgs_keys = []
for vgs_cfg in config['vgs']:
if 'name' not in vgs_cfg:
self._config_error("Missing 'name' in vgs config")
if 'base' not in vgs_cfg:
self._config_error("Missing 'base' in vgs config")
# Ensure we have a valid PVs backing this VG
for pvs in vgs_cfg['base']:
if not any(pv.name == pvs for pv in self.pvs):
self._config_error("base:%s in vgs does not "
"match a valid pvs" % pvs)
vgs_item = VgsNode(vgs_cfg['name'], state, vgs_cfg['base'],
vgs_cfg.get('options', None))
self.vgs.append(vgs_item)
# create logical volume nodes
self.lvs = []
for lvs_cfg in config['lvs']:
if 'name' not in lvs_cfg:
self._config_error("Missing 'name' in lvs config")
if 'base' not in lvs_cfg:
self._config_error("Missing 'base' in lvs config")
if 'size' not in lvs_cfg and 'extents' not in lvs_cfg:
self._config_error("Missing 'size' or 'extents' in lvs config")
# ensure this logical volume has a valid volume group base
if not any(vg.name == lvs_cfg['base'] for vg in self.vgs):
self._config_error("base:%s in lvs does not match a valid vg" %
lvs_cfg['base'])
lvs_item = LvsNode(lvs_cfg['name'], state, lvs_cfg['base'],
lvs_cfg.get('options', None),
lvs_cfg.get('size', None),
lvs_cfg.get('extents', None))
self.lvs.append(lvs_item)
# create the "driver" node
self.lvm_node = LVMNode(config['name'], state,
self.pvs, self.lvs, self.vgs)
def get_nodes(self):
# the nodes for insertion into the graph are all of the pvs,
# vgs and lvs nodes we have created above and the root node and
# the cleanup node.
return self.pvs + self.vgs + self.lvs \
+ [self.lvm_node]