Change root password failed (esex)

Environment:
XenServer, nova (esex), Ubuntu 12.4 VM

When I try to change root password using nova root-password command VM machine enter in status ERROR and password update failed on key_init

2012-09-20 11:20:41 DEBUG nova.virt.xenapi_conn [-] Got exception: ['XENAPI_PLUGIN_FAILURE', 'key_init', 'PluginError', 'TIMEOUT: No response from agent within 30 seconds.'] fro
m (pid=21300) _unwrap_plugin_exceptions /usr/lib/python2.7/dist-packages/nova/virt/xenapi_conn.py:611
2012-09-20 11:20:41 ERROR nova.virt.xenapi.vmops [req-3cbcb3ba-3088-48ee-b82c-c4e0431efc9f admin openstack] TIMEOUT: The call to key_init timed out. VM id=4a1cd016-6b18-4c64-ab9
a-221fe2720e8d; args={'path': '', 'dom_id': '178', 'id': 'f5d3de92-6c52-41c9-97cd-7ee9941b2d6e', 'pub': '26087257382505984794709304708086', 'host_uuid': '2b16f966-c04a-4f74-a6f7
-39b97a44aa69'}
2012-09-20 11:20:41 ERROR nova.virt.xenapi.vmops [req-3cbcb3ba-3088-48ee-b82c-c4e0431efc9f admin openstack] Failed to exchange keys: {'message': 'TIMEOUT: No response from agent
within 30 seconds.', 'returncode': 'timeout'}
2012-09-20 11:20:41 ERROR nova.compute.manager [req-3cbcb3ba-3088-48ee-b82c-c4e0431efc9f admin openstack] Failed to exchange keys: {'message': 'TIMEOUT: No response from agent w
ithin 30 seconds.', 'returncode': 'timeout'}
2012-09-20 11:20:41 TRACE nova.compute.manager Traceback (most recent call last):
2012-09-20 11:20:41 TRACE nova.compute.manager File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 1046, in set_admin_passw
ord
2012-09-20 11:20:41 TRACE nova.compute.manager self.driver.set_admin_password(instance_ref, new_pass)
2012-09-20 11:20:41 TRACE nova.compute.manager File "/usr/lib/python2.7/dist-packages/nova/virt/xenapi_conn.py", line 212, in set_admin_password
2012-09-20 11:20:41 TRACE nova.compute.manager self._vmops.set_admin_password(instance, new_pass)
2012-09-20 11:20:41 TRACE nova.compute.manager File "/usr/lib/python2.7/dist-packages/nova/virt/xenapi/vmops.py", line 996, in set_admin_password
2012-09-20 11:20:41 TRACE nova.compute.manager raise Exception(msg)
2012-09-20 11:20:41 TRACE nova.compute.manager Exception: Failed to exchange keys: {'message': 'TIMEOUT: No response from agent within 30 seconds.', 'returncode': 'timeout'}
2012-09-20 11:20:41 TRACE nova.compute.manager
2012-09-20 11:20:41 ERROR nova.rpc.amqp [req-3cbcb3ba-3088-48ee-b82c-c4e0431efc9f admin openstack] Exception during message handling
2012-09-20 11:20:41 TRACE nova.rpc.amqp Traceback (most recent call last):
2012-09-20 11:20:41 TRACE nova.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/rpc/amqp.py", line 253, in _process_data
2012-09-20 11:20:41 TRACE nova.rpc.amqp rval = node_func(context=ctxt, **node_args)
2012-09-20 11:20:41 TRACE nova.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/exception.py", line 114, in wrapped
2012-09-20 11:20:41 TRACE nova.rpc.amqp return f(*args, **kw)
2012-09-20 11:20:41 TRACE nova.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 159, in decorated_function
2012-09-20 11:20:41 TRACE nova.rpc.amqp function(self, context, instance_uuid, *args, **kwargs)
2012-09-20 11:20:41 TRACE nova.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 183, in decorated_function
2012-09-20 11:20:41 TRACE nova.rpc.amqp sys.exc_info())
2012-09-20 11:20:41 TRACE nova.rpc.amqp File "/usr/lib/python2.7/contextlib.py", line 24, in __exit__
2012-09-20 11:20:41 TRACE nova.rpc.amqp self.gen.next()
2012-09-20 11:20:41 TRACE nova.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 177, in decorated_function
2012-09-20 11:20:41 TRACE nova.rpc.amqp return function(self, context, instance_uuid, *args, **kwargs)
2012-09-20 11:20:41 TRACE nova.rpc.amqp File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 1071, in set_admin_password
2012-09-20 11:20:41 TRACE nova.rpc.amqp raise exception.NovaException(_msg)
2012-09-20 11:20:41 TRACE nova.rpc.amqp NovaException: Error setting admin password
2012-09-20 11:20:41 TRACE nova.rpc.amq

VM has xen-tools installed, but when i try to test it with

xenstore-write /local/domain/50/data/host/TEST_REQUEST1 "{ 'name': 'version', 'value:' 'agent' }"
or with
xenstore-write /local/domain/50/host/TEST_REQUEST1 "{ 'name': 'version', 'value:' 'agent' }"

(according to http://wiki.openstack.org/GuestAgentXenStoreCommunication) I don't get any answer. If I check on VM machine request with

xenstore-ls /local/domain/`xenstore-read domid`

request is there, but no one is answering.

Do I need anything more to install on VM (beside xenserver tools), and how should I check if everything is working on VM?