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WHY IS LVM THE WORST THING ON THIS PLANET

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brent s
2019-11-06 12:48:18 -05:00
parent f424938913
commit 5f8caf48d6
9 changed files with 241 additions and 38 deletions
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174
aif/disk/lvm.py
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@@ -1,3 +1,5 @@
import uuid
##
from . import _common
import aif.disk.block as block
import aif.disk.luks as luks
@@ -10,21 +12,181 @@ _BlockDev = _common.BlockDev
class PV(object):
def __init__(self, pv_xml, partobj):
self.xml = pv_xml
self.id = self.xml.attrib('id')
self.source = self.xml.attrib('source')
self.device = partobj
if not isinstance(self.device, (block.Disk,
block.Partition,
luks.LUKS,
mdadm.Array)):
raise ValueError(('partobj must be of type '
'aif.disk.block.Disk, '
'aif.disk.block.Partition, '
'aif.disk.luks.LUKS, or'
'aif.disk.mdadm.Array'))
_common.addBDPlugin('lvm')
self.devpath = None
pass
self.devpath = self.device.devpath
self.is_pooled = False
self.meta = None
self._parseMeta()
def _parseMeta(self):
# Note, the "UUID" for LVM is *not* a true UUID (RFC4122) so we don't convert it.
# https://unix.stackexchange.com/questions/173722/what-is-the-uuid-format-used-by-lvm
# TODO: parity with lvm_fallback.PV._parseMeta
# key names currently (probably) don't match and need to confirm the information's all present
meta = {}
try:
_meta = _BlockDev.lvm.pvinfo(self.devpath)
except _BlockDev.LVMError:
self.meta = None
self.is_pooled = False
return()
for k in dir(_meta):
if k.startswith('_'):
continue
elif k in ('copy',):
continue
v = getattr(_meta, k)
meta[k] = v
self.meta = meta
self.is_pooled = True
return()
def prepare(self):
try:
if not self.meta:
self._parseMeta()
if self.meta:
vg = self.meta['vg_name']
# LVM is SO. DUMB.
# If you're using LVM, seriously - just switch your model to mdadm. It lets you do things like
# remove disks live without restructuring the entire thing.
# That said, because the config references partitions/disks/arrays/etc. created *in the same config*,
# and it's all dependent on block devices defined in the thing, we can be reckless here.
# I'd like to take the time now to remind you to NOT RUN AIF-NG ON A "LIVE" MACHINE.
# At least until I can maybe find a better way to determine which LVs to reduce on multi-LV VGs
# so I can *then* use lvresize in a balanced manner, vgreduce, and pvmove/pvremove and not kill
# everything.
# TODO.
for lv in _BlockDev.lvm.lvs():
if lv.vg_name == vg:
_BlockDev.lvm.lvremove(vg, lv.lv_name)
_BlockDev.lvm.vgreduce(vg)
_BlockDev.lvm.vgremove(vg) # This *shouldn't* fail. In theory. But LVM is lel.
_BlockDev.lvm.pvremove(self.devpath)
# Or if I can get this working properly. Shame it isn't automagic.
# Seems to kill the LV by dropping a PV under it. Makes sense, but STILL. LVM IS SO DUMB.
# _BlockDev.lvm.vgdeactivate(vg)
# _BlockDev.lvm.pvremove(self.devpath)
# _BlockDev.lvm.vgreduce(vg)
# _BlockDev.lvm.vgactivate(vg)
##
self.meta = None
self.is_pooled = False
except _BlockDev.LVMError:
self.meta = None
self.is_pooled = False
u = uuid.uuid4()
opts = [_BlockDev.ExtraArg.new('--reportformat', 'json')]
# FUCK. LVM. You can't *specify* a UUID.
# u = uuid.uuid4()
# opts.append(_BlockDev.ExtraArg.new('--uuid', str(u)))
_BlockDev.lvm.pvcreate(self.devpath,
0,
0,
opts)
self._parseMeta()
return()
class VG(object):
def __init__(self, vg_xml, lv_objs):
def __init__(self, vg_xml):
self.xml = vg_xml
self.id = self.xml.attrib('id')
self.name = self.xml.attrib('name')
self.lvs = []
self.pvs = []
self.tags = []
for te in self.xml.findall('tags/tag'):
self.tags.append(te.text)
_common.addBDPlugin('lvm')
self.devpath = None
pass
self.devpath = self.name
self.info = None
def addPV(self, pvobj):
if not isinstance(pvobj, PV):
raise ValueError('pvobj must be of type aif.disk.lvm.PV')
pvobj.prepare()
self.pvs.append(pvobj)
return()
def create(self):
if not self.pvs:
raise RuntimeError('Cannot create a VG with no PVs')
opts = [_BlockDev.ExtraArg.new('--reportformat', 'json')]
# FUCK. LVM. You can't *specify* a UUID.
# u = uuid.uuid4()
# opts.append(_BlockDev.ExtraArg.new('--uuid', str(u)))
for t in self.tags:
opts.append(_BlockDev.ExtraArg.new('--addtag', t))
_BlockDev.lvm.vgcreate(self.name,
[p.devpath for p in self.pvs],
0,
opts)
for p in self.pvs:
p._parseMeta()
self.updateInfo()
return()
def createLV(self, lv_xml = None):
# If lv_xml is None, we loop through our own XML.
if lv_xml:
lv = LV(lv_xml, self)
lv.create()
self.lvs.append(lv)
else:
for le in self.xml.findall('logicalVolumes/lv'):
pass
self.updateInfo()
return()
def start(self):
_BlockDev.lvm.vgactivate(self.name)
self.updateInfo()
return()
def stop(self):
_BlockDev.lvm.vgdeactivate(self.name)
self.updateInfo()
return()
def updateInfo(self):
_info = _BlockDev.lvm.vginfo(self.name)
# TODO: parity with lvm_fallback.VG.updateInfo
# key names currently (probably) don't match and need to confirm the information's all present
info = {}
for k in dir(_info):
if k.startswith('_'):
continue
elif k in ('copy',):
continue
v = getattr(_info, k)
info[k] = v
self.info = info
return()
class LV(object):
def __init__(self, lv_xml, pv_objs):
def __init__(self, lv_xml, vgobj):
self.xml = lv_xml
self.id = self.xml.attrib('id')
self.name = self.xml.attrib('name')
self.size = self.xml.attrib('size') # Convert to bytes. Can get max from _BlockDev.lvm.vginfo(<VG>).free
self.vg = vg_obj
if not isinstance(self.vg, VG):
raise ValueError('vg_obj must be of type aif.disk.lvm.VG')
_common.addBDPlugin('lvm')
self.devpath = None
pass