VMware-to-KVM Resize Support for Instances Using Ephemeral Root Disks - #652
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VMware-to-KVM Resize Support for Instances Using Ephemeral Root Disks#652anokfireball wants to merge 4 commits into
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Cross-HV resize can use an image/local root only after conductor has a chance to convert it to BFV. The old utility-level BFV check rejected those instances before scheduling, so validate the root BDM in MigrationTask instead. Allow image/local and */volume roots. Reject blank/local, missing root BDMs, and cross-cell selections because the prep and abort RPCs run against the source cell. Change-Id: Ib66d7de2da1865437b0db9a2127cfd928c3ab073
KVM cannot boot a Nova-managed VMDK from a VMware ephemeral datastore, so an image/local root must be imported into Cinder before the existing BFV resize path runs. The conductor prep step powers off the source VM, detaches the root VMDK, imports it with manage_existing using source-name, size_gb, and optional source-id, creates a reserved attachment, and mutates the root BDM to volume-backed. The conversion is permanent across revert. Abort is only safe before Cinder relocates the disk; later code reports that through structured safe_to_abort metadata. Change-Id: I7e991b5da895b059a5b9f459c44ad3e4d5f93c3d
Cross-HV conversion needs a reversible source-side prep step around Cinder manage_existing. Add VMwareVMOps prep and abort helpers that detach the root VMDK and, when abort is safe, attach it back. Prep discovers the root disk before changing power state, accepts already shutdown guests, and powers the VM back on after detach failure only when Nova powered it off in this attempt. It returns the VMDK path, size, Cinder host, rollback device data, and optional FCD id needed by conductor. Abort is retry-tolerant: it skips reattach if the disk is already present and skips power-on if the VM is already running. Change-Id: I5b8057f8797d714c1e33f782a3b9f72a47f50407
Expose source-side prep and abort through compute RPC so conductor can drive VMware conversion without reaching into virt code. Bump compute RPC to 6.2.1, add driver stubs, delegate the VMware driver to VMops, and leave unsupported drivers on NotImplementedError. prep_cross_hv_conversion preserves DiskNotFound and InstanceInvalidState as expected RPC exceptions; abort failures remain unexpected and surface to the caller. Change-Id: I277618423e1fe881e56a36cd277b713bcc7a6cda
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| LOG.info('Detached root disk %(path)s from instance ' | ||
| '%(instance)s for cross-HV conversion.', | ||
| {'path': vmdk_path, 'instance': instance.uuid}) |
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| @mock.patch.object(fake_driver.FakeDriver, 'prep_cross_hv_conversion') | ||
| def test_prep_cross_hv_conversion(self, mock_prep): | ||
| mock_prep.return_value = { | ||
| 'vmdk_path': '[ds] uuid/uuid.vmdk', | ||
| 'size_bytes': 68719476736, | ||
| 'cinder_host': 'cinder-volume-vmware-vc@vmware_fcd', | ||
| 'rollback': { | ||
| 'controller_key': 1000, | ||
| 'unit_number': 0, | ||
| 'capacity_in_bytes': 68719476736, | ||
| }, | ||
| } | ||
| instance = fake_instance.fake_instance_obj(self.context) | ||
| result = self.compute.prep_cross_hv_conversion( | ||
| self.context, instance=instance) | ||
| mock_prep.assert_called_once_with(self.context, instance) | ||
| self.assertEqual(result['vmdk_path'], '[ds] uuid/uuid.vmdk') | ||
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| @mock.patch.object(fake_driver.FakeDriver, 'abort_cross_hv_conversion') | ||
| def test_abort_cross_hv_conversion(self, mock_abort): | ||
| instance = fake_instance.fake_instance_obj(self.context) | ||
| prep_data = { | ||
| 'vmdk_path': '[ds] uuid/uuid.vmdk', | ||
| 'size_bytes': 68719476736, | ||
| 'cinder_host': 'cinder-volume-vmware-vc@vmware_fcd', | ||
| 'rollback': { | ||
| 'controller_key': 1000, | ||
| 'unit_number': 0, | ||
| 'capacity_in_bytes': 68719476736, | ||
| }, | ||
| } | ||
| self.compute.abort_cross_hv_conversion( | ||
| self.context, instance=instance, prep_data=prep_data) | ||
| mock_abort.assert_called_once_with( | ||
| self.context, instance, prep_data) | ||
|
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do these tests test anything really? it seems as if it's 36 lines, to test oneliner wrapper methods?
anokfireball
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Aug 13, 2026
| flavor | ||
| * 6.1 - Add reimage_boot_volume parameter to rebuild_instance() | ||
| * 6.2 - Add target_state parameter to rebuild_instance() | ||
| * 6.2.1 - Add prep_cross_hv_conversion() and |
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We probably need another feature-flag toggle to roll this out consistently across the fleet.
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Implements Nova-side KVMotion support for image-backed VMware instances. This extends the BFV-only cross-HV resize flow from #627 to instances whose root disk is still a Nova-managed VMDK or FCD on a VMware ephemeral datastore. SCI KVM does not support ephemeral root disks, so Nova first converts the root disk to a Cinder FCD volume and then continues with the existing BFV resize path.
From the customer's point of view this stays a normal
nova resizeto a KVM flavor. After scheduling selects the KVM target, conductor detects the image-backed root and starts the conversion beforeprep_resize. The existingimage/localroot BDM is modified in place:source_type='image'and the image reference stay, while the BDM gets the new Cinder volume id and reserved attachment. This avoids creating a second root BDM for the same disk.The VMware driver provides the source-side prep and abort operations. Prep powers off the VM, detaches the root disk without deleting the backing files, and returns the VMDK path, disk size, Cinder host data, rollback data, and optional
VirtualDisk.vDiskId. Nova then calls the Cindermanage_existingwrapper withsource-name,size_gb, and optionalsource-id. Ifsource-idis present, Cinder can reuse the existing FCD id. Otherwise Cinder registers the detached VMDK as an FCD and relocates it to the Cinder datastore.Abort is only safe before Cinder crosses the storage point of no return. Nova can abort after synchronous Cinder failures and Cinder
errorstate. Nova must not abort aftererror_managing, because relocation may have started or finished. On timeout, Nova reads the latest volume state and only aborts if that state is definitely safe.The FCD volume type comes from
[cross_hv] fcd_volume_type, with no safe default because the correct type is deployment-specific. Missing config fails before Nova powers off the VM or detaches the disk. The Cinder manage wait uses[cross_hv] manage_existing_timeout.The conversion is permanent. Confirm leaves the instance BFV on KVM. Revert moves it back to VMware, but it stays BFV-on-VMware. A second resize after revert skips conversion and uses the BFV-only path directly.