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Add support for shared "backend_defaults" config

This gives a new config section that is shared for
all enabled_backends in a cinder.conf. This is optional
but can be used like:

[DEFAULT]
...
enabled_backends=lvm-1,lvm-2
...

[backend_defaults]
image_volume_cache_enabled = True
volume_clear = none
iscsi_helper = tgtadm
volume_driver = cinder.volume.drivers.lvm.LVMVolumeDriver

[lvm-1]
volume_group = stack-volumes-lvm-1

[lvm-2]
volume_group = stack-volumes-lvmd-2
lvm_type = thin

This also sets up the config helper to be easily
refactored to remove support for DEFAULT stanza
configured backends.

DocImpact: Need to document upgrade path and new
recommended config.
Implements: blueprint shared-backend-config
Change-Id: I2f94118b32076f264b3cf21caa259785fd415167
changes/99/335299/6
Patrick East 5 years ago
parent
commit
76016fffc9
  1. 38
      cinder/tests/unit/test_volume_configuration.py
  2. 4
      cinder/tests/unit/volume/test_volume.py
  3. 104
      cinder/volume/configuration.py
  4. 5
      releasenotes/notes/shared-backend-config-d841b806354ad5be.yaml

38
cinder/tests/unit/test_volume_configuration.py

@ -15,7 +15,6 @@
"""Tests for the configuration wrapper in volume drivers."""
from oslo_config import cfg
from cinder import test
@ -39,8 +38,12 @@ class VolumeConfigurationTest(test.TestCase):
def test_group_grafts_opts(self):
c = configuration.Configuration(volume_opts, config_group='foo')
self.assertEqual(c.str_opt, CONF.foo.str_opt)
self.assertEqual(c.bool_opt, CONF.foo.bool_opt)
self.assertEqual(c.str_opt, 'STR_OPT')
self.assertEqual(c.bool_opt, False)
self.assertEqual(c.str_opt, CONF.backend_defaults.str_opt)
self.assertEqual(c.bool_opt, CONF.backend_defaults.bool_opt)
self.assertIsNone(CONF.foo.str_opt)
self.assertIsNone(CONF.foo.bool_opt)
def test_opts_no_group(self):
c = configuration.Configuration(volume_opts)
@ -50,10 +53,33 @@ class VolumeConfigurationTest(test.TestCase):
def test_grafting_multiple_opts(self):
c = configuration.Configuration(volume_opts, config_group='foo')
c.append_config_values(more_volume_opts)
self.assertEqual(c.str_opt, CONF.foo.str_opt)
self.assertEqual(c.bool_opt, CONF.foo.bool_opt)
self.assertEqual(c.int_opt, CONF.foo.int_opt)
self.assertEqual(c.str_opt, 'STR_OPT')
self.assertEqual(c.bool_opt, False)
self.assertEqual(c.int_opt, 1)
# We get the right values, but they are coming from the backend_default
# group of CONF no the 'foo' one.
self.assertEqual(c.str_opt, CONF.backend_defaults.str_opt)
self.assertEqual(c.bool_opt, CONF.backend_defaults.bool_opt)
self.assertEqual(c.int_opt, CONF.backend_defaults.int_opt)
self.assertIsNone(CONF.foo.str_opt)
self.assertIsNone(CONF.foo.bool_opt)
self.assertIsNone(CONF.foo.int_opt)
def test_safe_get(self):
c = configuration.Configuration(volume_opts, config_group='foo')
self.assertIsNone(c.safe_get('none_opt'))
def test_backend_specific_value(self):
c = configuration.Configuration(volume_opts, config_group='foo')
# Set some new non-default value
CONF.set_override('str_opt', 'bar', group='backend_defaults')
actual_value = c.str_opt
self.assertEqual('bar', actual_value)
CONF.set_override('str_opt', 'notbar', group='foo')
actual_value = c.str_opt
# Make sure that we pick up the backend value and not the shared group
# value...
self.assertEqual('notbar', actual_value)

4
cinder/tests/unit/volume/test_volume.py

@ -2682,10 +2682,6 @@ class VolumeTestCase(base.BaseVolumeTestCase):
self.context)
self.assertEqual(expected_result, result)
def test_backup_use_temp_snapshot_config(self):
local_conf = self.volume.driver.configuration.local_conf
self.assertFalse(local_conf.backup_use_temp_snapshot)
@mock.patch('cinder.tests.fake_driver.FakeLoggingVolumeDriver.'
'SUPPORTS_ACTIVE_ACTIVE', True)
def test_set_resource_host_different(self):

104
cinder/volume/configuration.py

@ -46,36 +46,118 @@ CONF = cfg.CONF
SHARED_CONF_GROUP = 'backend_defaults'
class Configuration(object):
class DefaultGroupConfiguration(object):
"""Get config options from only DEFAULT."""
def __init__(self):
# set the local conf so that __call__'s know what to use
self.local_conf = CONF
def _ensure_config_values(self, volume_opts):
CONF.register_opts(volume_opts, group=None)
def append_config_values(self, volume_opts):
self._ensure_config_values(volume_opts)
def safe_get(self, value):
try:
return self.__getattr__(value)
except cfg.NoSuchOptError:
return None
def __getattr__(self, value):
# Don't use self.local_conf to avoid reentrant call to __getattr__()
local_conf = object.__getattribute__(self, 'local_conf')
return getattr(local_conf, value)
class BackendGroupConfiguration(object):
def __init__(self, volume_opts, config_group=None):
"""Initialize configuration.
This takes care of grafting the implementation's config
values into the config group
values into the config group and shared defaults. We will try to
pull values from the specified 'config_group', but fall back to
defaults from the SHARED_CONF_GROUP.
"""
self.config_group = config_group
# set the local conf so that __call__'s know what to use
if self.config_group:
self._ensure_config_values(volume_opts)
self.local_conf = CONF._get(self.config_group)
else:
self.local_conf = CONF
self._ensure_config_values(volume_opts)
self.backend_conf = CONF._get(self.config_group)
self.shared_backend_conf = CONF._get(SHARED_CONF_GROUP)
def _safe_register(self, opt, group):
try:
CONF.register_opt(opt, group=group)
except cfg.DuplicateOptError:
pass # If it's already registered ignore it
def _ensure_config_values(self, volume_opts):
CONF.register_opts(volume_opts, group=self.config_group)
"""Register the options in the shared group.
When we go to get a config option we will try the backend specific
group first and fall back to the shared group. We override the default
from all the config options for the backend group so we can know if it
was set or not.
"""
for opt in volume_opts:
self._safe_register(opt, SHARED_CONF_GROUP)
# Assuming they aren't the same groups, graft on the options into
# the backend group and override its default value.
if self.config_group != SHARED_CONF_GROUP:
self._safe_register(opt, self.config_group)
CONF.set_default(opt.name, None, group=self.config_group)
def append_config_values(self, volume_opts):
self._ensure_config_values(volume_opts)
def set_default(self, opt_name, default):
CONF.set_default(opt_name, default, group=SHARED_CONF_GROUP)
def get(self, key, default=None):
return getattr(self, key, default)
def safe_get(self, value):
try:
return self.__getattr__(value)
except cfg.NoSuchOptError:
return None
def __getattr__(self, opt_name):
# Don't use self.X to avoid reentrant call to __getattr__()
backend_conf = object.__getattribute__(self, 'backend_conf')
opt_value = getattr(backend_conf, opt_name)
if opt_value is None:
shared_conf = object.__getattribute__(self, 'shared_backend_conf')
opt_value = getattr(shared_conf, opt_name)
return opt_value
class Configuration(object):
def __init__(self, volume_opts, config_group=None):
"""Initialize configuration.
This shim will allow for compatibility with the DEFAULT
style of backend configuration which is used by some of the users
of this configuration helper, or by the volume drivers that have
all been forced over to the config_group style.
"""
self.config_group = config_group
if config_group:
self.conf = BackendGroupConfiguration(volume_opts, config_group)
else:
self.conf = DefaultGroupConfiguration()
def append_config_values(self, volume_opts):
self.conf.append_config_values(volume_opts)
def safe_get(self, value):
return self.conf.safe_get(value)
def __getattr__(self, value):
# Don't use self.local_conf to avoid reentrant call to __getattr__()
local_conf = object.__getattribute__(self, 'local_conf')
return getattr(local_conf, value)
# Don't use self.conf to avoid reentrant call to __getattr__()
conf = object.__getattribute__(self, 'conf')
return getattr(conf, value)

5
releasenotes/notes/shared-backend-config-d841b806354ad5be.yaml

@ -0,0 +1,5 @@
---
features:
- New config format to allow for using shared Volume Driver configuration
defaults via the [backend_defaults] stanza. Config options defined there
will be used as defaults for each backend enabled via enabled_backends.
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