openstack/nova
Code Issues Proposed changes

Check instance on dest once during block migration

Browse Source 
During live block migrations both pre_live_migration and
pre_block_migration check for the presence of the instance on
the destination and create the instance dir if it doesn't exist.

As a result the call to pre_block_migration always fails as
pre_live_migration has already created the instance dir on the
destination.

As it turns out the pre_block_migration call is completely
unnecessary. The libvirt driver is the only driver that uses the
call and the work it does can easily be done in the existing
pre_live_migration call. In order to streamline things we
completely remove the pre_block_migration call from all
drivers. Additionally we update the function definition for
pre_live_migration to pass needed disk info down to the
virt drivers.

Fixes bug: #1193359
Change-Id: Id9dfe482db3471d6a1b9b6c7d59a5ddc48775d7f
This commit is contained in:
Chet Burgess 2013-07-03 17:00:37 +00:00
parent 9e2d4ac460
commit 659ec75eaf
10 changed files with 35 additions and 83 deletions
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5
nova/compute/manager.py
View File

@ -3681,6 +3681,7 @@ class ComputeManager(manager.SchedulerDependentManager):
instance,
block_device_info,
self._legacy_nw_info(network_info),
disk,
migrate_data)
# NOTE(tr3buchet): setup networks on destination host
@ -3696,10 +3697,6 @@ class ComputeManager(manager.SchedulerDependentManager):
self.driver.ensure_filtering_rules_for_instance(instance,
self._legacy_nw_info(network_info))
# Preparation for block migration
if block_migration:
self.driver.pre_block_migration(context, instance, disk)
self._notify_about_instance_usage(
context, instance, "live_migration.pre.end",
network_info=network_info)

1
nova/tests/compute/test_compute.py
View File

@ -3901,6 +3901,7 @@ class ComputeTestCase(BaseTestCase):
self.compute.driver.pre_live_migration(mox.IsA(c), mox.IsA(instance),
{'block_device_mapping': []},
mox.IgnoreArg(),
mox.IgnoreArg(),
mox.IgnoreArg())
self.mox.StubOutWithMock(self.compute.driver,
'ensure_filtering_rules_for_instance')

2
nova/tests/virt/hyperv/test_hypervapi.py
View File

@ -684,7 +684,7 @@ class HyperVAPITestCase(test.TestCase):
self._mox.ReplayAll()
self._conn.pre_live_migration(self._context, instance,
block_device_info, network_info)
block_device_info, None, network_info)
self._mox.VerifyAll()
if cow:

52
nova/tests/virt/libvirt/test_libvirt.py
View File

@ -19,7 +19,6 @@ import copy
import errno
import eventlet
import fixtures
import json
import mox
import os
import re
@ -2528,6 +2527,11 @@ class LibvirtConnTestCase(test.TestCase):
def fixed_ips(self):
return ["test_ip_addr"]
def fake_none(*args, **kwargs):
return
self.stubs.Set(conn, '_create_images_and_backing', fake_none)
inst_ref = {'id': 'foo'}
c = context.get_admin_context()
nw_info = FakeNetworkInfo()
@ -2550,7 +2554,7 @@ class LibvirtConnTestCase(test.TestCase):
conn.plug_vifs(mox.IsA(inst_ref), nw_info)
self.mox.ReplayAll()
result = conn.pre_live_migration(c, inst_ref, vol, nw_info)
result = conn.pre_live_migration(c, inst_ref, vol, nw_info, None)
self.assertEqual(result, None)
def test_pre_live_migration_vol_backed_works_correctly_mocked(self):
@ -2562,6 +2566,11 @@ class LibvirtConnTestCase(test.TestCase):
{'connection_info': 'dummy', 'mount_device': '/dev/sdb'}]}
conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
def fake_none(*args, **kwargs):
return
self.stubs.Set(conn, '_create_images_and_backing', fake_none)
class FakeNetworkInfo():
def fixed_ips(self):
return ["test_ip_addr"]
@ -2587,50 +2596,13 @@ class LibvirtConnTestCase(test.TestCase):
'block_migration': False,
'instance_relative_path': inst_ref['name']
}
ret = conn.pre_live_migration(c, inst_ref, vol, nw_info,
ret = conn.pre_live_migration(c, inst_ref, vol, nw_info, None,
migrate_data)
self.assertEqual(ret, None)
self.assertTrue(os.path.exists('%s/%s/' % (tmpdir,
inst_ref['name'])))
db.instance_destroy(self.context, inst_ref['uuid'])
def test_pre_block_migration_works_correctly(self):
# Replace instances_path since this testcase creates tmpfile
with utils.tempdir() as tmpdir:
self.flags(instances_path=tmpdir)
# Test data
instance_ref = db.instance_create(self.context, self.test_instance)
dummy_info = [{'path': '%s/disk' % tmpdir,
'disk_size': 10737418240,
'type': 'raw',
'backing_file': ''},
{'backing_file': 'otherdisk_1234567',
'path': '%s/otherdisk' % tmpdir,
'virt_disk_size': 10737418240}]
dummyjson = json.dumps(dummy_info)
# qemu-img should be mockd since test environment might not have
# large disk space.
self.mox.StubOutWithMock(imagebackend.Image, 'cache')
imagebackend.Image.cache(context=mox.IgnoreArg(),
fetch_func=mox.IgnoreArg(),
filename='otherdisk_1234567',
image_id=self.test_instance['image_ref'],
project_id='fake',
size=10737418240L,
user_id=None).AndReturn(None)
self.mox.ReplayAll()
conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
conn.pre_block_migration(self.context, instance_ref,
dummyjson)
self.assertTrue(os.path.exists('%s/%s/' %
(tmpdir, instance_ref['uuid'])))
db.instance_destroy(self.context, instance_ref['uuid'])
def test_get_instance_disk_info_works_correctly(self):
# Test data
instance_ref = db.instance_create(self.context, self.test_instance)

2
nova/tests/virt/xenapi/test_xenapi.py
View File

@ -3092,7 +3092,7 @@ class XenAPILiveMigrateTestCase(stubs.XenAPITestBase):
# ensure method is present
stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
self.conn = xenapi_conn.XenAPIDriver(fake.FakeVirtAPI(), False)
self.conn.pre_live_migration(None, None, None, None)
self.conn.pre_live_migration(None, None, None, None, None)
def test_post_live_migration_at_destination(self):
# ensure method is present

16
nova/virt/driver.py
View File

@ -474,29 +474,19 @@ class ComputeDriver(object):
"""
raise NotImplementedError()
def pre_live_migration(self, ctxt, instance_ref,
block_device_info, network_info,
migrate_data=None):
def pre_live_migration(self, ctxt, instance_ref, block_device_info,
network_info, disk_info, migrate_data=None):
"""Prepare an instance for live migration
:param ctxt: security context
:param instance_ref: instance object that will be migrated
:param block_device_info: instance block device information
:param network_info: instance network information
:param disk_info: instance disk information
:param migrate_data: implementation specific data dict.
"""
raise NotImplementedError()
def pre_block_migration(self, ctxt, instance_ref, disk_info):
"""Prepare a block device for migration
:param ctxt: security context
:param instance_ref: instance object that will have its disk migrated
:param disk_info: information about disk to be migrated (as returned
from get_instance_disk_info())
"""
raise NotImplementedError()
def live_migration(self, ctxt, instance_ref, dest,
post_method, recover_method, block_migration=False,
migrate_data=None):

2
nova/virt/fake.py
View File

@ -382,7 +382,7 @@ class FakeDriver(driver.ComputeDriver):
return
def pre_live_migration(self, context, instance_ref, block_device_info,
network_info, migrate_data=None):
network_info, disk, migrate_data=None):
return
def unfilter_instance(self, instance_ref, network_info):

2
nova/virt/hyperv/driver.py
View File

@ -115,7 +115,7 @@ class HyperVDriver(driver.ComputeDriver):
block_migration, migrate_data)
def pre_live_migration(self, context, instance, block_device_info,
network_info, migrate_data=None):
network_info, disk, migrate_data=None):
self._livemigrationops.pre_live_migration(context, instance,
block_device_info,
network_info)

27
nova/virt/libvirt/driver.py
View File

@ -1438,7 +1438,9 @@ class LibvirtDriver(driver.ComputeDriver):
# NOTE (rmk): Re-populate any missing backing files.
disk_info_json = self.get_instance_disk_info(instance['name'], xml,
block_device_info)
self._create_images_and_backing(context, instance, disk_info_json)
instance_dir = libvirt_utils.get_instance_path(instance)
self._create_images_and_backing(context, instance, instance_dir,
disk_info_json)
# Initialize all the necessary networking, block devices and
# start the instance.
@ -3395,7 +3397,7 @@ class LibvirtDriver(driver.ComputeDriver):
instance['project_id'])
def pre_live_migration(self, context, instance, block_device_info,
network_info, migrate_data=None):
network_info, disk_info, migrate_data=None):
"""Preparation live migration."""
# Steps for volume backed instance live migration w/o shared storage.
is_shared_storage = True
@ -3422,6 +3424,10 @@ class LibvirtDriver(driver.ComputeDriver):
raise exception.DestinationDiskExists(path=instance_dir)
os.mkdir(instance_dir)
# Ensure images and backing files are present.
self._create_images_and_backing(context, instance, instance_dir,
disk_info)
if is_volume_backed and not (is_block_migration or is_shared_storage):
# Touch the console.log file, required by libvirt.
console_file = self._get_console_log_path(instance)
@ -3467,28 +3473,21 @@ class LibvirtDriver(driver.ComputeDriver):
instance=instance)
greenthread.sleep(1)
def pre_block_migration(self, context, instance, disk_info_json):
"""Preparation for block migration."""
# NOTE (rmk): When preparing for a block migration, the instance dir
# should not exist on the destination hypervisor.
instance_dir = libvirt_utils.get_instance_path(instance)
if os.path.exists(instance_dir):
raise exception.DestinationDiskExists(path=instance_dir)
os.mkdir(instance_dir)
self._create_images_and_backing(context, instance, disk_info_json)
def _create_images_and_backing(self, context, instance, disk_info_json):
def _create_images_and_backing(self, context, instance, instance_dir,
disk_info_json):
"""
:params context: security context
:params instance:
nova.db.sqlalchemy.models.Instance object
instance object that is migrated.
:params instance_dir:
instance path to use, calculated externally to handle block
migrating an instance with an old style instance path
:params disk_info_json:
json strings specified in get_instance_disk_info
"""
disk_info = jsonutils.loads(disk_info_json)
instance_dir = libvirt_utils.get_instance_path(instance)
for info in disk_info:
base = os.path.basename(info['path'])

9
nova/virt/xenapi/driver.py
View File

@ -465,13 +465,6 @@ class XenAPIDriver(driver.ComputeDriver):
"""
pass
def pre_block_migration(self, ctxt, instance_ref, disk_info_json):
"""Used by libvirt for live migration. We rely on xenapi
checks to do this for us. May be used in the future to
populate the vdi/vif maps.
"""
pass
def live_migration(self, ctxt, instance_ref, dest,
post_method, recover_method, block_migration=False,
migrate_data=None):
@ -495,7 +488,7 @@ class XenAPIDriver(driver.ComputeDriver):
recover_method, block_migration, migrate_data)
def pre_live_migration(self, context, instance_ref, block_device_info,
network_info, migrate_data=None):
network_info, data, migrate_data=None):
"""Preparation live migration.
:params block_device_info: