Terminating an instance with --libvirt_type=lxc fails, can't detach loop device

[Xavi Campa]

Seems like the container is still running when nova tries to detach the container, therefore failing:

root@compute01:~# fuser -m /dev/loop1
/dev/loop1: 15525rce 15535rce 18189rce 18197rce 18203rce 18214rce

The processes:
15525 ? Ss 0:00 /sbin/init
15535 ? S 0:00 /sbin/plymouthd --mode=boot --attach-to-session
18189 ? S 0:00 upstart-udev-bridge --daemon
18197 ? Ss 0:00 /usr/sbin/sshd -D
18203 ? Sl 0:00 rsyslogd -c4
18214 ? S<s 0:00 udevd --daemon

Trace:
2011-09-04 16:18:31,704 INFO nova.virt.libvirt_conn [-] instance instance-00000110: deleting instance files /var/lib/nova/instances/instance-00000110
2011-09-04 16:18:31,706 DEBUG nova.utils [-] Running cmd (subprocess): sudo umount /var/lib/nova/instances/instance-00000110/rootfs from (pid=15094) execute /usr/lib/pymodules/python2.7/nova/utils.py:165
2011-09-04 16:18:31,867 DEBUG nova.utils [-] Running cmd (subprocess): sudo losetup -a from (pid=15094) execute /usr/lib/pymodules/python2.7/nova/utils.py:165
2011-09-04 16:18:32,033 DEBUG nova.utils [-] Running cmd (subprocess): sudo losetup --detach /dev/loop1 from (pid=15094) execute /usr/lib/pymodules/python2.7/nova/utils.py:165
2011-09-04 16:18:32,184 DEBUG nova.utils [-] Result was 1 from (pid=15094) execute /usr/lib/pymodules/python2.7/nova/utils.py:180
2011-09-04 16:18:32,208 ERROR nova.exception [-] Uncaught exception
(nova.exception): TRACE: Traceback (most recent call last):
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/exception.py", line 98, in wrapped
(nova.exception): TRACE: return f(*args, **kw)
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/compute/manager.py", line 117, in decorated_function
(nova.exception): TRACE: function(self, context, instance_id, *args, **kwargs)
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/compute/manager.py", line 492, in terminate_instance
(nova.exception): TRACE: self._shutdown_instance(context, instance_id, 'Terminating')
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/compute/manager.py", line 483, in _shutdown_instance
(nova.exception): TRACE: self.driver.destroy(instance, network_info)
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/virt/libvirt/connection.py", line 326, in destroy
(nova.exception): TRACE: self._cleanup(instance)
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/virt/libvirt/connection.py", line 336, in _cleanup
(nova.exception): TRACE: disk.destroy_container(target, instance, nbd=FLAGS.use_cow_images)
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/virt/disk.py", line 159, in destroy_container
(nova.exception): TRACE: _unlink_device(device, nbd)
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/virt/disk.py", line 190, in _unlink_device
(nova.exception): TRACE: utils.execute('losetup', '--detach', device, run_as_root=True)
(nova.exception): TRACE: File "/usr/lib/pymodules/python2.7/nova/utils.py", line 188, in execute
(nova.exception): TRACE: cmd=' '.join(cmd))
(nova.exception): TRACE: ProcessExecutionError: Unexpected error while running command.
(nova.exception): TRACE: Command: sudo losetup --detach /dev/loop1
(nova.exception): TRACE: Exit code: 1
(nova.exception): TRACE: Stdout: ''
(nova.exception): TRACE: Stderr: "loop: can't delete device /dev/loop1: Device or resource busy\n"
(nova.exception): TRACE:
2011-09-04 16:18:32,218 ERROR nova.rpc [-] Exception during message handling
(nova.rpc): TRACE: Traceback (most recent call last):
(nova.rpc): TRACE: File "/usr/lib/pymodules/python2.7/nova/rpc/impl_kombu.py", line 620, in _process_data
(nova.rpc): TRACE: rval = node_func(context=ctxt, **node_args)
(nova.rpc): TRACE: File "/usr/lib/pymodules/python2.7/nova/exception.py", line 129, in wrapped
(nova.rpc): TRACE: raise Error(str(e))
(nova.rpc): TRACE: Error: Unexpected error while running command.
(nova.rpc): TRACE: Command: sudo losetup --detach /dev/loop1
(nova.rpc): TRACE: Exit code: 1
(nova.rpc): TRACE: Stdout: ''
(nova.rpc): TRACE: Stderr: "loop: can't delete device /dev/loop1: Device or resource busy\n"

Using these versions:
ii nova-common 2011.3~rc~20110903.1526-0ubuntu0ppa1~natty1 OpenStack Compute - common files
ii nova-compute 2011.3~rc~20110903.1526-0ubuntu0ppa1~natty1 OpenStack Compute - compute node
ii nova-compute-kvm 2011.3~rc~20110903.1526-0ubuntu0ppa1~natty1 OpenStack Compute - compute node (KVM)

My configuration:
--cc_host=controller
--ec2_url=http://controller:8773/services/Cloud
--ec2_host=controller
--rabbit_host=controller
--network_manager=nova.network.manager.VlanManager
--flat_interface=eth0
--fixed_range=172.16.0.0/16
--network_size=256
--sql_connection=mysql://nova:passW0rd@controller/nova
--glance_api_servers=glance:9292
--image_service=nova.image.glance.GlanceImageService
--network_host=controller
--vnc_console_proxy_url=http://controller:6080
--vncproxy_url=http://controller:6080
--vncproxy_host=controller
--vnc_enabled=False
--minimum_root_size=2147483648
--iscsi_ip_prefix=192.168.191
--libvirt_type=lxc
--use_cow_images=False

My DB version:
44