Hi, I updated my engine and 1 host to 4.2 from 4.1 and now I cannot start a VM and get this error: "UnsupportedType: Unsupported {} for ioTune". My other 6 4.1 hosts are able to start VM normally with the new 4.2 engine. My VM has this inside: <iotune read_bytes_sec="0" read_iops_sec="100" total_bytes_sec="0" total_iops_sec="0" write_bytes_sec="0" write_iops_sec="100"/> error: 1. 2018-05-17 14:30:38,006+0200 ERROR (vm/0d53dd5d) [virt.vm] (vmId='0d53dd5d-ef16-4763-bbdc-2dc173087bf5') The vm start process failed (vm:943) 2. Traceback (most recent call last): 3.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 872, in _startUnderlyingVm 4.     self._run() 5.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 2882, in _run 6.     self._domDependentInit() 7.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 2458, in _domDependentInit 8.     self._vmDependentInit() 9.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 2495, in _vmDependentInit 10.     self._sync_metadata() 11.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 5158, in _sync_metadata 12.     self._md_desc.dump(self._dom) 13.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 509, in dump 14.     md_xml = self._build_xml() 15.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 721, in _build_xml 16.     md_elem = self._build_tree(namespace, namespace_uri) 17.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 711, in _build_tree 18.     dev_elem = _dump_device(metadata_obj, data) 19.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 800, in _dump_device 20.     elems.append(_dump_device_spec_params(md_obj, value)) 21.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 866, in _dump_device_spec_params 22.     spec_params_elem = md_obj.dump(_SPEC_PARAMS, **value) 23.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 229, in dump 24.     _keyvalue_to_elem(self._add_ns(key), value, elem) 25.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 916, in _keyvalue_to_elem 26.     raise UnsupportedType(key, value) 27. UnsupportedType: Unsupported {} for ioTune 28. 2018-05-17 14:30:38,006+0200 INFO (vm/0d53dd5d) [virt.vm] (vmId='0d53dd5d-ef16-4763-bbdc-2dc173087bf5') Changed state to Down: Unsupported {} for ioTune (code=1) (vm:1683) 29. 2018-05-17 14:30:38,007+0200 ERROR (vm/0d53dd5d) [root] FINISH thread <Thread(vm/0d53dd5d, stopped daemon 140237644748544)> failed (concurrent:201) 30. Traceback (most recent call last): 31.   File "/usr/lib/python2.7/site-packages/vdsm/common/concurrent.py", line 194, in run 32.     ret = func(*args, **kwargs) 33.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 944, in _startUnderlyingVm 34.     self.setDownStatus(ERROR, vmexitreason.GENERIC_ERROR, str(e)) 35.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 1685, in setDownStatus 36.     self._update_metadata() 37.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 5145, in _update_metadata 38.     self._sync_metadata() 39.   File "/usr/lib/python2.7/site-packages/vdsm/virt/vm.py", line 5158, in _sync_metadata 40.     self._md_desc.dump(self._dom) 41.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 509, in dump 42.     md_xml = self._build_xml() 43.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 721, in _build_xml 44.     md_elem = self._build_tree(namespace, namespace_uri) 45.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 711, in _build_tree 46.     dev_elem = _dump_device(metadata_obj, data) 47.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 800, in _dump_device 48.     elems.append(_dump_device_spec_params(md_obj, value)) 49.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 866, in _dump_device_spec_params 50.     spec_params_elem = md_obj.dump(_SPEC_PARAMS, **value) 51.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 229, in dump 52.     _keyvalue_to_elem(self._add_ns(key), value, elem) 53.   File "/usr/lib/python2.7/site-packages/vdsm/virt/metadata.py", line 916, in _keyvalue_to_elem 54.     raise UnsupportedType(key, value) 55. UnsupportedType: Unsupported {} for ioTune