hosted-engine deployment hang at "[INFO] Waiting for cluster 'Default' to become operatonal..."

Issue

• hosted-engine deployment hang at "[INFO] Waiting for cluster 'Default' to become operatonal..."
• The deployment will fail due to timeout error.
• Similar call trace is like below:

2014-04-14 21:39:29 DEBUG otopi.plugins.ovirt_hosted_engine_setup.engine.add_host add_host._wait_cluster_cpu_ready:254 cluster <ovirtsdk.infrastructure.brokers.Cluster object at 0x4389a50> cluster.__dict__ {'_Base__context': 67282448, 'glusterhooks': <ovirtsdk.infrastructure.brokers.ClusterGlusterHooks object at 0x4389090>, 'glustervolumes': <ovirtsdk.infrastructure.brokers.ClusterGlusterVolumes object at 0x4389150>, 'superclass': <ovirtsdk.xml.params.Cluster object at 0x4389990>, 'networks': <ovirtsdk.infrastructure.brokers.ClusterNetworks object at 0x4389d90>, 'permissions': <ovirtsdk.infrastructure.brokers.ClusterPermissions object at 0x4389510>}
2014-04-14 21:39:29 INFO otopi.plugins.ovirt_hosted_engine_setup.engine.add_host add_host._wait_cluster_cpu_ready:263 Waiting for cluster 'Default' to become operational...
2014-04-14 21:39:30 ERROR otopi.plugins.ovirt_hosted_engine_setup.engine.add_host add_host._wait_cluster_cpu_ready:269 Timed out while waiting for cluster to become ready. Please check the logs.
2014-04-14 21:39:30 DEBUG otopi.context context._executeMethod:137 method exception
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/otopi/context.py", line 127, in _executeMethod
    method['method']()
  File "/usr/share/ovirt-hosted-engine-setup/scripts/../plugins/ovirt-hosted-engine-setup/engine/add_host.py", line 468, in _closeup
    self.logger.debug(cpu.__dict__)
AttributeError: 'NoneType' object has no attribute '__dict__'
2014-04-14 21:39:30 ERROR otopi.context context._executeMethod:146 Failed to execute stage 'Closing up': 'NoneType' object has no attribute '__dict__'