Comment 3 for bug 1213209

"libvirtError: Timed out during operation: cannot acquire state change lock" happens when getting the second snapshot against the same server.

2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp Traceback (most recent call last):
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/openstack/common/rpc/amqp.py", line 421, in _process_data
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp **args)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/openstack/common/rpc/dispatcher.py", line 172, in dispatch
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp result = getattr(proxyobj, method)(ctxt, **kwargs)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/exception.py", line 100, in wrapped
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp temp_level, payload)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/exception.py", line 77, in wrapped
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp return f(self, context, *args, **kw)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/compute/manager.py", line 241, in decorated_function
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp pass
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/compute/manager.py", line 227, in decorated_function
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp return function(self, context, *args, **kwargs)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/compute/manager.py", line 269, in decorated_function
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp e, sys.exc_info())
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/compute/manager.py", line 256, in decorated_function
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp return function(self, context, *args, **kwargs)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/compute/manager.py", line 2157, in snapshot_instance
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp update_task_state)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/new/nova/nova/virt/libvirt/driver.py", line 1300, in snapshot
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp virt_dom.managedSave(0)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/usr/local/lib/python2.7/dist-packages/eventlet/tpool.py", line 179, in doit
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp result = proxy_call(self._autowrap, f, *args, **kwargs)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/usr/local/lib/python2.7/dist-packages/eventlet/tpool.py", line 139, in proxy_call
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp rv = execute(f,*args,**kwargs)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/usr/local/lib/python2.7/dist-packages/eventlet/tpool.py", line 77, in tworker
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp rv = meth(*args,**kwargs)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp File "/usr/lib/python2.7/dist-packages/libvirt.py", line 696, in managedSave
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp if ret == -1: raise libvirtError ('virDomainManagedSave() failed', dom=self)
2013-08-16 05:45:28.738 21074 TRACE nova.openstack.common.rpc.amqp libvirtError: Timed out during operation: cannot acquire state change lock