when using ceph as backend, instance can resize to a smaller flavor successfully without any exception, ResizeError failed to raise.
when using ceph as backend, xml file looks like this:
<disk type='network' device='disk'>
<driver name='qemu' type='raw' cache='writeback'/>
<auth username='cinder'>
<secret type='ceph' uuid='457eb676-33da-42ec-9a8c-9293d545c337'/>
</auth>
<source protocol='rbd' name='vms/e888e9c5-4c63-4ec3-a8fe-45a432cc82e0_disk'>
<host name='172.16.40.18' port='6789'/>
</source>
<target dev='vda' bus='virtio'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
</disk>
As the disk type is network, so get_instance_disk_info cannot get disk_info
nova/virt/libvirt/driver.py:
def _get_instance_disk_info(self, instance_name, xml,
block_device_info=None):
......
for cnt, path_node in enumerate(path_nodes):
disk_type = disk_nodes[cnt].get('type')
path = path_node.get('file') or path_node.get('dev')
target = target_nodes[cnt].attrib['dev']
if not path:
LOG.debug('skipping disk for %s as it does not have a path',
instance_name)
continue
if disk_type not in ['file', 'block']:
LOG.debug('skipping disk because it looks like a volume', path)
continue
if target in volume_devices:
LOG.debug('skipping disk %(path)s (%(target)s) as it is a '
'volume', {'path': path, 'target': target})
continue
......
nova/virt/libvirt/driver.py:
@staticmethod
def _is_booted_from_volume(instance, disk_mapping):
"""Determines whether the VM is booting from volume
Determines whether the disk mapping indicates that the VM
is booting from a volume.
"""
return ((not bool(instance.get('image_ref')))
or 'disk' not in disk_mapping)
In the end when migrate_disk_and_power_off calling is_booted_from_volume, disk_mapping = [] and treated as volume backed instance.
Which version of nova are you hitting this on? Does it exist in the latest release (mitaka)?