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Parse block device lvm lvs size attributes

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The block device lvm lvs `size` attribute was passed directly to
lvcreate, so using units M, G means base 2. All other block device
size values are parsed with accepted conventions of M, B being base 10
and MiB, GiB being base 2.

lvm lvs `size` attributes are now parsed the same as other size
attributes. This improves consistency and makes it practical to
calculate volume sizes to fill the partition size. This means existing
size values will now create slightly smaller volumes. Previous sizes
can be restored by changing the unit to MiB, GiB, or increasing the
value for a base 10 unit.

The impact on this change should be minimal, the only known uses of lvm
volumes (TripleO, and element block-device-efi-lvm) uses extents
percentage instead of size. The smaller sizes can always be increased
after deployment.

Requested sizes will also be rounded down to align with physical
extents (4MiB). Previously specifying a value which did not align on
4MiB would consume an extra extent which could unexpectedly consume
more than the partition size.

Change-Id: Ia109cc5105071d82cc895d8d9cb85bc47da20a7a
This commit is contained in:
Steve Baker 2022-04-29 10:49:03 +12:00
parent 527e75a6de
commit d090126c66
3 changed files with 42 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
diskimage_builder/block_device/level1/lvm.py
View File

@ -19,7 +19,9 @@ from diskimage_builder.block_device.exception \
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__)
@ -180,7 +182,8 @@ class LvsNode(NodeBase):
:param state: global state pointer
:param base: the parent volume group
:param options: options passed to lvcreate
:param size: size of the LV, in MB (this or extents must be provided)
: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)
@ -193,7 +196,10 @@ class LvsNode(NodeBase):
cmd = ["lvcreate", ]
cmd.extend(['--name', self.name])
if self.size:
cmd.extend(['-L', 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:

34
diskimage_builder/block_device/tests/test_lvm.py
View File

@ -104,12 +104,18 @@ class TestLVM(tc.TestGraphGeneration):
mock.call(['vgcreate', 'vg',
'/dev/fake/root', '/dev/fake/data', '--force']),
# create a bunch of lv's on vg
mock.call(['lvcreate', '--name', 'lv_root', '-L', '1800M', 'vg']),
mock.call(['lvcreate', '--name', 'lv_tmp', '-L', '100M', 'vg']),
mock.call(['lvcreate', '--name', 'lv_var', '-L', '500M', 'vg']),
mock.call(['lvcreate', '--name', 'lv_log', '-L', '100M', 'vg']),
mock.call(['lvcreate', '--name', 'lv_audit', '-L', '100M', 'vg']),
mock.call(['lvcreate', '--name', 'lv_home', '-L', '200M', 'vg'])]
mock.call(['lvcreate', '--name', 'lv_root', '-L', '1799356416B',
'vg']),
mock.call(['lvcreate', '--name', 'lv_tmp', '-L', '96468992B',
'vg']),
mock.call(['lvcreate', '--name', 'lv_var', '-L', '499122176B',
'vg']),
mock.call(['lvcreate', '--name', 'lv_log', '-L', '96468992B',
'vg']),
mock.call(['lvcreate', '--name', 'lv_audit', '-L', '96468992B',
'vg']),
mock.call(['lvcreate', '--name', 'lv_home', '-L', '197132288B',
'vg'])]
self.assertEqual(mock_exec_sudo.call_count, len(cmd_sequence))
mock_exec_sudo.assert_has_calls(cmd_sequence)
@ -216,17 +222,17 @@ class TestLVM(tc.TestGraphGeneration):
'/dev/fake/data', '--force']),
# create a bunch of lv's on vg
mock.call(['lvcreate', '--name', 'lv_root',
'-L', '1800M', 'vg1']),
'-L', '1799356416B', 'vg1']),
mock.call(['lvcreate', '--name', 'lv_tmp',
'-L', '100M', 'vg1']),
'-L', '96468992B', 'vg1']),
mock.call(['lvcreate', '--name', 'lv_var',
'-L', '500M', 'vg2']),
'-L', '499122176B', 'vg2']),
mock.call(['lvcreate', '--name', 'lv_log',
'-L', '100M', 'vg2']),
'-L', '96468992B', 'vg2']),
mock.call(['lvcreate', '--name', 'lv_audit',
'-L', '100M', 'vg2']),
'-L', '96468992B', 'vg2']),
mock.call(['lvcreate', '--name', 'lv_home',
'-L', '200M', 'vg2'])]
'-L', '197132288B', 'vg2'])]
self.assertListEqual(mock_exec_sudo.call_args_list,
cmd_sequence)
@ -389,9 +395,9 @@ class TestLVM(tc.TestGraphGeneration):
'/dev/fake/data1', '/dev/fake/data2', '--force']),
# create root and data volume
mock.call(['lvcreate', '--name', 'lv_root',
'-L', '1800M', 'vg_root']),
'-L', '1799356416B', 'vg_root']),
mock.call(['lvcreate', '--name', 'lv_data',
'-L', '2G', 'vg_data'])
'-L', '1996488704B', 'vg_data'])
]
self.assertListEqual(mock_exec_sudo.call_args_list,

14
releasenotes/notes/lvm-size-unit-c6b790b87d15c53d.yaml Normal file
View File

@ -0,0 +1,14 @@
---
other:
- |
The block device lvm lvs `size` attribute was passed directly to lvcreate,
so using units M, G means base 2. All other block device size values are
parsed with accepted conventions of M, B being base 10 and MiB, GiB being
base 2. lvm lvs `size` attributes are now parsed the same as other size
attributes. This improves consistency and makes it practical to calculate
volume sizes to fill the partition size. This means existing size values
will now create slightly smaller volumes. Previous sizes can be restored by
changing the unit to MiB, GiB, or increasing the value for a base 10 unit.
Requested sizes will also be rounded down to align with physical extents
(4MiB).